ei-sensor

Temperature Sensors in Water Treatment & Purification

Mon, 30 Mar 2026 15:53:00 GMT

Water treatment and water purification systems operate across municipal plants, industrial facilities, food processing operations, and medical environments. Each application involves tightly controlled processes designed to remove contaminants, manage biological activity, and deliver water that meets regulatory and performance standards.

Temperature plays a direct role in how these systems perform. Chemical reactions shift as temperatures rise or fall. Biological treatment stages respond to even small changes in thermal conditions. Filtration performance, membrane efficiency, and disinfection processes all depend on stable operating ranges.

Accurate temperature sensing allows operators and equipment manufacturers to monitor process conditions in real time. Reliable data supports process control decisions, protects equipment from overheating, and contributes to consistent water quality. For OEMs developing treatment skids, filtration modules, or purification equipment, sensor selection influences both performance and long-term reliability.

Why Temperature Measurement Matters in Water & Wastewater Processes

Water and wastewater treatment systems rely on controlled chemical, biological, and mechanical processes. Temperature directly affects reaction rates, microbial activity, and equipment performance across each stage of treatment.

In biological treatment tanks, bacteria break down organic material at specific temperature ranges. If the water temperature drops too low, microbial activity slows and treatment efficiency declines. Elevated temperatures can stress biological cultures and reduce process stability.

Chemical dosing systems are also temperature sensitive. Reaction speed changes as temperature shifts, which can impact coagulation, flocculation, and disinfection performance. Without accurate measurement, operators may struggle to maintain consistent results.

Membrane filtration and reverse osmosis systems respond to temperature changes through variations in pressure and flow characteristics. Warmer water can increase permeate flow rates, while colder conditions may reduce efficiency and increase energy consumption.

Temperature sensing provides real-time feedback to control systems, allowing operators to adjust heaters, pumps, or chemical dosing rates. It also helps protect motors, pumps, and control panels from overheating during extended operation.

Where Temperature Sensors Are Used in Water Treatment Systems

Water treatment equipment includes multiple stages where temperature measurement plays a functional role in both process control and equipment protection. Sensor placement depends on system design and treatment method.

Biological Treatment Tanks

Activated sludge systems and aerobic digesters rely on stable thermal conditions to maintain microbial activity. Temperature sensors installed directly in tanks or recirculation lines provide operators with data needed to monitor biological performance.

Chemical Mixing and Dosing Systems

Coagulation, flocculation, and pH adjustment processes involve controlled chemical reactions. Sensors positioned in mixing chambers or injection lines help track reaction conditions and maintain consistent dosing performance.

Filtration and Membrane Systems

Ultrafiltration and reverse osmosis units are sensitive to water temperature changes. Sensors located near membrane housings or feed lines allow operators to monitor performance shifts tied to viscosity and pressure variation.

Disinfection Systems

UV treatment chambers and thermal disinfection units depend on specific operating ranges. Temperature measurement within these systems confirms that process conditions remain within design parameters.

Pumps, Motors, and Control Panels

Beyond process stages, temperature sensors are installed in pump housings, motor windings, and electrical enclosures. Monitoring these components helps prevent overheating during continuous operation.

Strategic sensor placement throughout treatment equipment provides accurate thermal data where it directly impacts system performance and equipment life.

Choosing the Right Temperature Sensor for Water Applications

Water treatment environments expose sensors to moisture, chemicals, pressure changes, and continuous operation. Selecting the right sensing element depends on the application point, required accuracy, and mechanical design of the equipment.

RTDs for Accuracy and Stability

RTDs are frequently used in process lines, tanks, and membrane systems where consistent, repeatable measurement is required. They offer strong long-term stability and operate across a wide temperature range, making them suitable for municipal and industrial treatment equipment.

Platinum RTD elements are commonly selected for applications that require tighter tolerances and reliable performance over extended service intervals.

Thermistors for Fast Response

NTC thermistors are ideal for localized monitoring inside control panels, pump assemblies, and compact treatment modules. Their high sensitivity allows quick detection of temperature changes, which is useful in protection circuits and automated control systems.

Thermistors typically operate within a narrower temperature range than RTDs, but they provide excellent responsiveness in that span.

Construction and Material Considerations

Sensor housings must tolerate chemical exposure and constant moisture contact. Stainless steel probes are widely used in water processing systems due to their corrosion resistance and durability. Sealing methods and lead wire insulation should match the operating environment, especially in high-humidity or washdown areas.

For many OEMs, application-specific probe assemblies provide better integration than standard catalog components. Selecting the proper sensor design early in the engineering process simplifies installation and improves long-term measurement performance.

Custom Temperature Sensor Solutions for OEM Water Treatment Equipment

Water treatment equipment varies widely in size and configuration. Municipal systems, skid-mounted purification units, and industrial recycling platforms each present different space constraints and control requirements. Standard components do not always align with these designs.

Custom temperature sensing solutions allow OEMs to specify:

Probe length and diameter for pipe or tank integration

Threaded or compression fittings for direct process contact

Resistance values and tolerances matched to control systems

Lead wire insulation suited for moisture and washdown conditions

Connector types compatible with existing assemblies

Membrane housings may require compact probe designs. Chemical dosing systems may call for materials that tolerate cleaning agents or treatment chemicals. Control panels often require small thermistor assemblies positioned near heat-generating components.

EI Sensor Technologies collaborates closely with OEM teams to develop RTD and thermistor probe assemblies built to application requirements , allowing straightforward installation and dependable long-term operation in water purification equipment.

Why OEMs Partner with EI Sensor Technologies for Precision Temperature Measurement

Water purification equipment requires accurate, repeatable temperature sensing built for long service life in moisture-heavy and chemically exposed environments. OEMs look for a sensor partner that understands performance targets, production timelines, and long-term reliability.

EI Sensor Technologies brings more than 30 years of experience in RTD and thermistor manufacturing. Our team collaborates directly with OEM engineers to develop standard and custom probe assemblies that meet your drawings and application specifications. We focus on consistent quality, technical knowledge, and responsive communication throughout the project.

Email sales@ei-sensor.com to discuss your water treatment temperature sensing requirements or request a quote.

Why Thermistors Matter in Fire Safety Devices

Thu, 19 Feb 2026 20:48:30 GMT

Fire safety systems are designed to detect threats early, activate alarms, and help protect people and property. At the core of many of these systems are components that respond to changes in temperature. Thermistors, a type of temperature sensor, are widely used in fire detection because of their accuracy, speed, and long-term reliability. Fire safety devices often operate under strict regulatory standards. The sensors used must meet precise response times and accuracy levels to comply with industry codes and provide dependable protection. Understanding how thermistors function and why they’re chosen over other sensor types helps explain their important role in modern fire safety technology.

Understanding Thermistors

Thermistors are temperature-sensitive resistors. Their resistance changes when the surrounding temperature changes. There are two main types: Negative Temperature Coefficient (NTC) thermistors , which decrease in resistance as temperature rises, and Positive Temperature Coefficient (PTC) thermistors , which increase in resistance with heat.

This behavior makes them especially useful in applications that need fast and reliable temperature detection. NTC thermistors are commonly used in fire safety devices because they offer high sensitivity in lower temperature ranges, which helps detect the earliest signs of heat buildup.

The performance of a thermistor depends on the materials used during manufacturing, which are selected for predictable and stable resistance behavior. EI Sensor offers thermistors with tightly controlled resistance curves to meet a range of fire safety design requirements.

Thermistors are also compact, stable over time, and relatively simple to integrate into circuits. These features make them a practical solution for many industries looking to monitor temperature, control systems, or trigger alarms.

Fire Safety Devices That Use Thermistors

Thermistors are commonly found in devices designed to detect heat, smoke, or flame. In many smoke detectors, heat detectors, and fire alarms, thermistors serve as the component that senses a rapid rise in temperature. Once a threshold is reached, the system sends a signal to activate an alert or initiate a safety response.

Sprinkler systems can also use thermistors to monitor ambient temperature and trigger water flow when heat from a fire is detected. Some flame detectors use them in combination with infrared sensors to improve accuracy and reduce false alarms.

In newer smart detection systems, thermistors continue to provide reliable temperature sensing, even in compact wireless designs. Their durability allows them to perform in enclosed housings exposed to dust, humidity, or vibration.

In commercial buildings, industrial settings, and even residential systems, thermistors help these devices operate more reliably. Their quick reaction to temperature shifts allows systems to activate sooner, giving people more time to respond.

Thermistors vs. Other Temperature Sensors

When designing fire safety systems, choosing the right type of temperature sensor matters. Thermistors, RTDs (Resistance Temperature Detectors), and thermocouples are three common options, each suited for different tasks.

RTDs offer high accuracy over a wide r ange of temperatures but are generally larger and slower to respond than thermistors. Thermocouples can handle extreme heat and are useful in high-temperature industrial environments, but they may lack the sensitivity needed for early-stage fire detection.

Thermistors stand out in fire safety because they combine speed, sensitivity, and compact size. They react faster than RTDs and are more precise at lower temperature ranges than thermocouples. For many fire detection systems, that makes thermistors the more practical choice, especially in enclosed or densely packed devices.

Thermistors are also more cost-effective in high-volume manufacturing, which makes them ideal for consumer and commercial fire safety products. Their resistance profiles can be tailored to meet specific setpoints, something that's harder to achieve with other sensor types.

EI Sensor’s Expertise in Fire Safety Applications

EI Sensor Technologies supports OEMs across multiple industries where fire detection plays a key role in protecting people, equipment, and facilities. Our thermistors are built to meet the performance needs of fire safety equipment that depends on accurate, fast-responding temperature sensors.

A wide range of NTC thermistors and thermistor probe assemblies are available to support different fire safety applications. Sensor characteristics such as response speed, thermal time constant, and resistance curves can be tailored to meet specific system requirements.

Standard components don’t always fit the design or performance needs of every product. EI Sensor works directly with engineering teams to develop thermistor-based solutions that match custom specifications. These solutions often address space limitations, harsh environments, or temperature thresholds that require tightly controlled detection points.

Our team brings decades of hands-on experience to each project and helps customers make confident decisions around sensor design. When speed, stability, and reliability matter, we help simplify the process of finding the right fit.

Let’s Talk About Your Application Needs

If you’re working on a fire safety device and need reliable, accurate temperature sensing, we can help. EI Sensor specializes in thermistor solutions built for fast response and dependable performance in demanding environments.

Email us at sales@ei-sensor.com to discuss your application or request engineering support .

Thermistor Averaging Sensors Explained

Thu, 22 Jan 2026 22:12:22 GMT

Temperature monitoring and control in large spaces comes with unique challenges. Airflow, sunlight, equipment heat, and insulation gaps can all create hot or cold spots. In these situations, one sensor may not give reliable temperature data that represents the average temperature across the entire area.

Thermistor averaging sensors are designed to solve that problem. They collect readings from multiple points, then produce a single averaged value. This approach helps systems operate more efficiently and respond more accurately to real conditions.

What is an Averaging Sensor?

This is paragraph text. Click it or hit the Manage Text button to change the font, color, size, format, and more. To set up site-wide paragraph and title styles, go to Site Theme. An averaging sensor is a temperature-sensing device built to measure conditions across a wider area rather than a single spot. Instead of relying on one sensing element, it typically contains multiple sensing elements spaced along its length. These points are connected in a way that produces a single output value, representing the average temperature across the monitored area.

In thermistor averaging sensors, each sensing point uses an NTC thermistor . As temperature rises, resistance decreases. When wired together, the combined resistance gives a reading that reflects the full temperature profile of the space, not just a single point reading.

These sensors are often housed in flexible cables or semi-rigid probes and come in different lengths to match the size and layout of the space being me asured.

How Averaging Sensors Differ from Standard Probes

Standard probes read temperature at a single point. That works well in controlled environments, but in large areas with varying thermal conditions a single point sensor may provide inaccurate data.

Averaging sensors collect input from multiple points along their length and combine it into one output. This gives a more accurate indication of the systems overall thermal status.

They’re usually longer and more flexible, suited for ducts or extended surfaces. Standard probes are usually rigid and made for fixed point temperat ure measurements.

How Averaging Sensors Work

Averaging sensors operate using a set of thermistors placed at intervals along a flexible or rigid averaging assembly. Each sensing point detects its local temperature, but the sensor doesn’t report these individually. Instead, it blends the input into one resistance value that reflects an average temperature of the overall area being sensed.

This design helps stabilize the temperature signal in areas where readings can fluctuate from point to point. Instead of overreacting to thermal spikes near a vent or draft, the system receives a more consistent signal tied to the full space being measured.

Most averaging sensors use a parallel circuit to keep the output predictable and compatible with standard controllers. This approach supports smoother control responses and avoids overcorrection based on isolated temperature swing s.

Applications of Thermistor Averaging Sensors

These sensors are used in systems that require temperature input from more than one location. Common examples include HVAC ductwork, large enclosures, and any equipment with uneven thermal conditions.

HVAC and Building Automation

In HVAC systems, temperature readings can be skewed by vents, air movement, or heat from nearby equipment. This can cause uneven zone control or unnecessary cycling.

Thermistor averaging sensors reduce that risk by collecting input from multiple points along the duct. The output gives a balanced reading that helps maintain steady performance across the system.

In building automation, this leads to more accurate feedback and less need for manual correction .

Medical Equipment and Lab Environments

In lab settings and medical devices, even small temperature changes can affect performance. Equipment like incubators, refrigeration units, and climate-controlled storage often requires a uniform environment across shelves, chambers, or enclosures.

Thermistor averaging sensors help maintain that consistency by monitoring multiple points inside the controlled space. Instead of reacting to a warm or cool spot, the system adjusts based on a more complete view of overall internal conditions.

Industrial and Process Control Systems

Large equipment and enclosures often develop uneven temperature zones during operation. Heat from motors, drives, or power supplies can cause local hot spots that don’t represent overall conditions.

Averaging sensors give a more balanced view of temperature across these areas. This helps maintain safe operating ranges, improves control accuracy, and reduces the risk of overcorrecting based on a single reading.

They’re also used in temperature-sensitive production processes, where tight control is needed to maintain quality.

Advantages of Using Averaging Sensors

These sensors offer practical benefits across a range of systems. They help improve data quality, reduce system noise caused by fluctuating readings, and contribute to more stable operation over time.

Improved Temperature Accuracy Over Larger Areas

Temperature can vary across ducts, panels, or enclosures. A single sensor might catch a draft or hotspot, while missing the overall pattern.

Averaging sensors reduces tha t risk by gathering data from multiple points and smoothing out localized shifts. This helps maintain steady control and avoids unnecessary system reactions based on outliers.

Enhanced Reliability in Variable Environments

Systems exposed to shifting airflow, equipment heat, or irregular loads often see quick changes in temperature. These fluctuations can cause inconsistent readings and unnecessary adjustments.

Averaging sensors help reduce that issue. Multiple sensing points spread across the space produce a steadier signal that reflects general conditions rather than isolated spikes .

Versatility in Sensor Placement and Installation

Averaging sensors offer flexible mounting options for a wide range of system layouts. They’re available in different lengths and formats to fit tight spaces, follow long duct runs, or cover extended surfaces.

This makes them a practical choice for engineers and system designers working around size constraints or uneven heat distribution .

Why Choose EI Sensor for Your Temperature Sensing Needs

EI Sensor manufactures high-quality thermistor averaging sensors for HVAC, medical, industrial, and other demanding applications. Our sensors are built for accuracy, long-term reliability, and compatibility with real-world system requirements.

We work directly with OEMs and engineers to develop both standard and custom sensing solutions. Our focus is on delivering components that meet application-specific needs without overcomplicating the process.

Email sales@ei-sensor.com to start a conversation about your temperature sensing project or request design support.

What Is an Inrush Current Limiter? Types, Uses, & Benefits

Fri, 09 Jan 2026 19:44:06 GMT

Inrush current limiters suppress the current surge that occurs when switching mode power supplies, motor drives, transformers, and other devices are turned on. The high initial starting current can harm these systems and components, so inrush current limiters are applied to minimize the spike and harmful effects. The most popular types of inrush current limiters are negative temperature coefficient (NTC) thermistors and positive temperature coefficient (PTC) thermistors .

What is an Inrush Current Limiter?

When the initial power is turned on, the initial current drawn by electrical devices is the inrush current, which can be many times higher than the normal running operating current. Failure to manage the initial current spike can damage equipment and its components or cause blown fuses and tripped circuit breakers. Current spikes can also reduce equipment reliability and durability, and stress power supplies, sometimes making the equipment inoperable.

Inrush current limiters are devices that prevent these spikes by limiting the amount of current at start-up and subsequently allowing normal current flow so that the system starts and operates as desi gned.

How Do Inrush Current Limiters Work?

Inrush current limiters minimize inrush current spikes. Inrush current limiters are often thermistors or thermally sensitive resistors whose resistance changes significantly due to the inrush current flow through the device. While there are several types of inrush current limiters, their core function is to minimize the current spike that occurs at turn-on from passing through and damaging the system’s sensitive components.

Their resistance drops significantly after initially limiting the current flow, and the reduced resistance allows the normal running current to flow freely, so the system starts and operates properly.

Advantages of Using an Inrush Current Limiter

Inrush current limiters provide a single device solution value by safeguarding systems, offering enhanced functionality, and providing design and cost advantages over alternatives.

Safeguard Systems and Components. Inrush current limiters limit the initial current surges that can damage sensitive components like capacitors, rectifiers, and power switches during turn-on. They also improve system reliability by preventing blown fuses and tripped circuit breakers that keep systems from operating or operating correctly. Excessive Inrush current also increases the wear on many components, so inrush current limiters extend the operational life of those components.

Design and Cost. Most inrush current limiters are small, so they easily fit on electronic circuits and in other applications where size matters. Thermistors are also an inexpensive single component solution compared to the complex active circuits that can be used as alternatives.

Types of Inrush Current Limiters

Negative temperature coefficient (NTC) thermistors exhibit less resistance at higher temperatures, while positive temperature coefficient (PTC) thermistors show more resistance at higher temperatures. While NTC thermistors are widely used as inrush current limiters, PTCs are advantageous for some applications.

Inrush NTC Thermistors

Negative temperature coefficient (NTC) thermistors are the most common inrush current limiters. Made of sintered metal oxides pressed into ceramic disks, they provide high room temperature resistance and prevent high turn-on current flows. After the NTC protects against the initial spike, it self-heats, and its resistance drops significantly, allowing increasing amounts of current to flow, which allows the system to start and operate correctly.

Inrush PTC Thermistors

While NTC thermistors are more commonly used as inrush current limiters than PTCs, PTCs are preferred for some applications.

Situations that use PTCs often involve ambient temperatures that ar e much higher or much lower than room temperature. When temperatures are high, NTC resistance may be too low to protect the system, while at low temperatures, it may be too high to allow the system to turn on.

Applications of Inrush Current Limiters

The primary application for inrush current limiters involves systems in which significant initial current surges can cause damage, particularly those with large input capacitors drawing a high initial current. Applications in which inrush current limiters offer value include those listed below.

Power Supply Components. Protects rectifiers and input capacitors from inrush currents

Motor Soft Start. Prevents current spikes when starting large electrical motors

Lighting Applications. Extends the life of fluorescent and halogen lamps by limiting the current surge when turned on

Medical equipment. Limits inrush current surges to medical devices with high power requirements, such as magnetic resonance imaging (MRI) devices.

Looking for an Inrush Current Limiter?

Your choice of inrush current limiters may vary based on the frequency of on-off cycles, voltage, cost, and other requirements. EI Sensor offers a range of standard and custom NTC and PTC thermistors you can order directly from EI Sensor or through our stocking distributors . Let us apply our expertise to solve a problem with inrush current limiters or ensure you use the best product for your application.

EI Sensor’s Inrush Current Limiters

If you have questions about temperature sensors or inrush current limiters, contact us for help. If our standard inrush current limiters do not meet your application needs, let’s discuss your requirements, and we can discuss developing a custom solution for you.

How Temperature Sensors Improve Efficiency in HVAC Systems

Fri, 09 Jan 2026 16:00:13 GMT

Efficient temperature regulation is essential in HVAC systems. Accurate sensing helps equipment maintain thermal balance, optimize energy use, and respond to changing environmental conditions. Without reliable data, systems may overcompensate, cycle too frequently, or operate outside ideal parameters.

Thermistors and RTDs are used throughout HVAC equipment to monitor temperatures in air handling units, refrigeration lines, compressors, and more. These sensors provide the precision needed to improve control strategies, reduce energy consumption, and meet performance targets .

The Role of Temperature Sensors in HVAC Systems

Temperature sensors are embedded throughout HVAC equipment to enable consistent system control. Their output is used to monitor refrigerant conditions, air temperature, and equipment surface temperatures. These readings guide operational decisions such as when to engage compressors, modulate airflow, or initiate defrost cycles.

In advanced systems, sensors provide continuous feedback for variable-speed components and digitally controlled valves. This level of control improves precision and supports demand-based operation. Without accurate temperature input, system responsiveness can suffer, leading to inefficiencies or uneven thermal performance.

The placement and specification of each HVAC temperature sensor is critical to achieving the desired system behavior. Proper integration helps manufacturers meet both functional goals and user expectations.

Boosting Energy Efficiency with Precision Sensors

Energy efficiency in HVAC systems depends on precise temperature data. Accurate readings allow system controllers to make real-time adjustments that minimize energy use without sacrificing performance. When sensors track temperature changes quickly and reliably, systems can reduce short cycling, maintain tighter setpoints, and avoid running longer than necessary.

Thermistors and RTDs are both well-suited for this role. Their fast response and stable performance over time make them effective for modulating fan speeds, controlling compressors, and adjusting refrigerant flow. These optimizations lead to measurable energy savings across a range of HVAC-R applications.

Using a high-quality HVAC temperature sensor helps manufacturers and facility operators lower operating costs and achieve better system efficiency, especially in environments with variable loads or fluctuating ambient temperature s.

Meeting Environmental and Regulatory Standards

Modern HVAC systems must meet increasing demands for sustainability and regulatory compliance. Energy codes, refrigerant regulations, and building efficiency standards all place pressure on manufacturers and system designers to improve thermal control and reduce environmental impact.

Temperature sensors play a key role in helping systems comply with these requirements. Consistent thermal monitoring enables better refrigerant management, limits unnecessary energy use, and supports equipment operation within defined performance thresholds.

Accurate thermal data also supports documentation and system validation during audits or inspections.

Applications Across HVAC Components

Temperature sensors are used throughout HVAC systems to monitor and control key processes. Each application has unique performance demands, from rapid response times to long-term stability in high-moisture environments.

Evaporator and Condenser Coils

Sensors placed near coils help monitor refrigerant temperature and system load. This data is used to optimize compressor cycling and prevent coil freezing or overheating.

Compressor Systems

Monitoring discharge and suction line temperatures ensures the compressor operates within safe limits. Sensors also help detect inefficiencies that could lead to mechanical failure or reduced cooling capacity.

Air Handling Units (AHUs)

Sensors measure supply and return air temperatures to control fan speed, damper position, and reheat operations. Stable readings contribute to consistent indoor climate control.

Refrigerant Lines

Line sensors track superheat and subcooling values, which are critical to system balance. Accurate sensing improves charge diagnostics and overall system efficiency.

Defrost Controls

In refrigeration applications, sensors trigger defrost cycles based on coil temperature. This approach prevents ice buildup and maintains airflow without wasting energy.

Zone Controls and Smart Thermostat

Room-level sensors provide temperature data for zoning systems and smart thermostats. These inputs help optimize comfort and reduce energy use in multi-zone buildings.

Thermistors vs. RTDs: Choosing the Right Sensor

Both thermistors and RTDs are used in HVAC systems, but selecting the right sensor depends on application-specific needs such as temperature range, accuracy, size, and response time.

Thermistors are commonly used in HVAC applications due to their fast response and high sensitivity in narrower temperature ranges. They are ideal for monitoring air and refrigerant temperatures where compact form factors and cost-efficiency are priorities. NTC thermistors , in particular, offer a steep resistance change over small temperature shifts, which is beneficial for responsive control.

RTDs (Resistance Temperature Detectors) provide excellent accuracy and long-term stability across a wider temperature range. They are more commonly used in industrial or large-scale commercial HVAC systems where durability and precision outweigh cost concerns. RTDs are well-suited for components exposed to extreme or fluctuating conditions over extended periods.

EI Sensor’s Contribution to Smarter HVAC Solutions

EI Sensor Technologies partners with HVAC manufacturers to deliver high-performance sensing solutions built for today’s system demands. With decades of experience in temperature sensing, the team supports OEMs with both standard components and custom assemblies designed for energy efficiency, thermal control, and long-term reliability.

A wide selection of thermistors and RTDs is available for use in air handling units, compressor protection, refrigerant monitoring, and defrost systems. Each sensor is built for stable performance, quick response, and seamless integration with modern control platforms.

For applications that require a tailored approach, EI Sensor offers engineering support to modify tolerances, adjust packaging, or design fully custom probe assemblies that align with system specifications.

Get Started with EI Sensor Technologies

HVAC systems continue to advance in performance, energy efficiency, and compliance. EI Sensor Technologies provides the temperature sensing solutions required to meet these evolving demands through proven standard parts and custom assemblies designed for specific system needs.

If you're developing HVAC equipment and need reliable sensors or engineering input, we're ready to assist.

Email us at sales@ei-sensor.com to discuss your requirements, request a quote, or connect with our technical tea m .

Top Applications for Temperature Sensors Across Sectors

Mon, 05 Jan 2026 21:39:55 GMT

Temperature sensors are used in a wide range of equipment, systems, and environments. Manufacturers and engineers rely on them to maintain performance, protect components, and meet safety or compliance requirements. These sensors help control heating and cooling, manage energy usage, and provide accurate measurements in processes where stability matters.

EI Sensor Technologies designs and manufactures thermistors, RTDs, and probe assemblies for both standard and highly specialized applications. Customers across multiple sectors rely on that expertise for consistent performance, application-specific designs, and responsive engineering.

Why Temperature Sensors Matter Across Industries

Temperature control affects safety, efficiency, and product quality in nearly every technical environment. Sensors are used to regulate heating and cooling, prevent overheating, maintain sanitation standards, and support precise operation in sensitive equipment.

These sensors are often selected for environments that involve extreme heat, variable moisture, or compact installation spaces.

Top Industries Where Temperature Sensors Are Used

Temperature sensors are used in sectors where thermal control affects safety, performance, or product integrity. Industries like HVAC , medical , industrial automation, and food processing depend on accurate readings to keep systems stable and operations consistent.

HVAC

Heating, ventilation, air conditioning, and refrigeration systems rely on temperature sensors to regulate airflow, monitor coolant levels, and maintain setpoints. In both residential and commercial systems, accurate readings help improve energy efficiency and prevent system failures.

NTC thermistors are commonly used in these systems due to their sensitivity and fast response times. Sensors may be placed near evaporator coils, compressors, or ambient air pathways to monitor performance and control cycling.

Building Automation and Smart Infrastructure

Modern building systems use temperature sensors to manage energy use, occupant comfort, and equipment efficiency. Sensors are integrated into smart thermostats, zoning controls, and automated HVAC systems to track temperature changes across rooms and zones.

Accurate sensing allows centralized systems to respond in real time, adjusting airflow or heating based on occupancy or outdoor conditions. Thermistors and RTDs are both used in these setups, depending on the accuracy and range required.

Industrial and Manufacturing Equipment

Industrial equipment often operates under extreme or fluctuating temperatures. Sensors are used to monitor motors, bearings, heaters, and process chambers to prevent overheating and maintain stable production conditions.

RTDs are frequently selected for their wide temperature range and long-term stability. Thermistors are also used in applications requiring fast response in tighter temperature bands. Accurate measurement helps reduce downtime, extend equipment life, and maintain product consistency.

Medical Devices and Healthcare Applications

Temperature sensors play a key role in patient safety, diagnostic accuracy, and device performance . They are used in equipment such as patient monitoring systems, sterilization units, imaging machines, and laboratory instruments.

NTC thermistors are often chosen for their precision in narrow temperature ranges, making them ideal for applications like body temperature monitoring or sample preservation. Reliability and consistency are especially important in clinical environments where performance cannot vary.

Appliance and Consumer Products

Household and commercial appliances rely on temperature sensors to manage heating, cooling, and safety functions. Common applications include ovens, refrigerators , dishwashers, dryers, and water heaters.

Thermistors are widely used due to their small size and fast response. These sensors help regulate temperature cycles, detect faults, and improve energy efficiency. Accurate control also supports product longevity and user safety.

Food Handling and Processing

Temperature sensors are used throughout food storage, preparation, and transport to meet safety standards and preserve product quality. Sensors monitor conditions in refrigeration units, cooking systems, and holding equipment to keep temperatures within strict limits.

Thermistors and RTDs are selected based on the range and durability required. In environments exposed to moisture or frequent cleaning, sensors must be sealed and built for long-term use without performance drift.

Custom Sensor Solutions for Unique Applications

Some projects require temperature sensors that fall outside standard specifications. A design might need an unusual resistance curve, a special mounting method, or materials that withstand cleaning agents and other environmental factors. Off-the-shelf parts are not always a match for these requirements.

EI Sensor works with OEMs to create thermistors, RTDs, and probe assemblies that align with precise electrical, mechanical, and durability goals. Customization can include unique encapsulation methods, extended temperature ranges, or non-standard lead configurations.

The Value of Partnering with an Experienced Sensor Manufacturer

The right sensor supplier helps keep development on schedule, improves system reliability, and reduces the risk of performance issues. Delays, unclear specifications, or inconsistent parts can create setbacks that are hard to recover from. EI Sensor combines decades of experience with responsive service and a strong focus on application-ready solutions. OEMs across HVAC-R, medical, industrial, and other sectors rely on their thermistors, RTDs, and probe assemblies to meet both standard and highly specific design goals.

To discuss your temperature sensing requirements or request a quote, contact the team at sales@ei-sensor.com .

Why Pool & Spa Temperature Sensors Matter

Thu, 18 Dec 2025 20:38:48 GMT

Temperature plays a bigger role in pool and spa management than most people realize. It affects chemical reactions, equipment function, and user comfort. When water temperature drifts too far from the recommended range, chemical treatments stop working the way they should. That can lead to cloudy water, pH instability, scaling, or corrosion.

A pool temperature sensor helps maintain steady readings so other systems can do their job. Most modern pools and spas use automated controls for heating, filtration, and chemical dosing. Those systems rely on accurate temperature input to make the right adjustments at the right time. Without consistent feedback, it’s harder to keep water balanced or prevent overcorrection.

In commercial settings, this becomes even more important. Public health standards, energy use, and customer satisfaction all depend on proper temperature control. Even in residential systems, poor temperature sensing can mean wasted energy, shortened equipment life, or repeated chemical adjustments.

The Science of Temperature and Pool Chemistry

Chemical behavior in pools and spas depends heavily on water temperature. As water warms up, reaction rates increase. Chlorine works faster but also breaks down sooner. In colder water, reactions slow down and chlorine lasts longer, though it may take longer to disinfect.

Temperature shifts can also throw off pH. When water gets warmer, pH tends to rise. That makes chlorine less effective and can lead to cloudy water or scale. Lower pH, on the other hand, may lead to corrosion or skin irritation. Neither extreme is good for swimmers or system components.

Calcium hardness becomes more difficult to manage when temperatures swing. Warm water mixed with high calcium levels often causes scale to form inside heaters and pipes, reducing water flow and efficiency. Cooling systems too quickly can also disturb chemical stability.

Saltwater pools react to temperature as well. In cooler conditions, some salt cells stop producing chlorine entirely. If there's no backup chlorination plan, sanitizer levels drop, and water quality degrades.

Every part of pool chemistry depends on a steady baseline. Temperature is one of the first values to move out of range, so tracking it early keeps other problems from spreading.

Temperature and Water Quality

Water temperature influences how clean the water looks, how safe it is to swim in, and how hard the system has to work to keep it that way. Warmer water speeds up bacterial growth and creates better conditions for algae. It also increases chlorine demand, since higher temperatures make chlorine degrade faster.

As the temperature rises, swimmers tend to sweat more. Sunscreen, body oils, and other organic material build up faster in warm water, placing extra strain on filters and sanitizers. If the system can't keep up, water may turn cloudy, develop odors, or require more frequent adjustments.

Cold water slows everything down. Chlorine takes longer to work, and organic debris may not break down as efficiently. In pools with uneven heating or poor circulation, colder zones can disrupt water treatment, even if the rest of the system is working correctly.

Stable temperature helps the rest of the system do its job. When water stays in range, filters work more efficiently, chlorine remains effective longer, and chemical use stays more predictable.

Sensor Technology in Pool & Spa Systems

Temperature sensors are a key part of how modern pools and spas function. They supply data that control systems use to manage heating and water treatment. Without reliable input, automated adjustments often miss the mark.

Most pool systems use either thermistors or RTDs to measure water temperature. Thermistors are widely used in both residential and commercial settings. They respond quickly to temperature changes and work well in water because of their sensitivity and compact form. RTDs are built for more demanding environments, where long-term stability and tighter accuracy matter more than cost.

Sensor housing and placement affect how well the sensor performs. In pools and spas, sensors are often installed in-line, near heater outlets, or embedded in a manifold. If the sensor sits in a low-flow area or is exposed to air during pump shutdowns, the readings can become unreliable. This leads to poor control decisions and unnecessary system cycling.

Material choice also matters. Sensors exposed to pool water need to resist corrosion from chlorine, bromine, or salt systems. Stainless steel, epoxy coatings, or thermoplastic housings are common options, depending on the chemistry and temperature range involved.

When matched correctly to the system and environment, a temperature sensor becomes a dependable component that supports smooth operation. It helps maintain stable water conditions and keeps heating and dosing systems res ponsive.

Benefits of Accurate Temperature Monitoring

Using a reliable temperature sensor improves how the entire system functions. Key advantages include:

Lower energy use

Heaters run more efficiently when they respond to accurate readings, avoiding unnecessary runtime.

More stable water chemistry

Consistent temperature helps chemical dosing stay on target, reducing spikes in sanitizer levels or pH drift.

When temperature changes are tracked closely, it's easier to spot circulation problems, heater faults, or system imbalances early.

Faster issue detection

Less equipment strain

Pumps, heaters, and salt cells last longer when they aren’t overworked due to bad data or temperature swings.

Better water clarity

Balanced temperature helps filters and sanitizers handle organic material more effectively, which keeps water clean.

Fewer maintenance calls

Well-regulated systems need fewer manual corrections, which saves time for technicians and reduces service interruptions.

Improved comfort for users

Water that stays within the desired range feels better and creates a more consistent experience for swimmers.

Choosing the Right Sensor for Your Pool or Spa

The best sensor for a pool or spa depends on how the system runs, where the sensor is installed, and how the water is treated.

Thermistors are a common choice. They respond quickly, work well in water, and are cost-effective. NTC thermistors are often used in systems that need fast feedback for heating or dosing .

RTDs offer better long-term accuracy and are often used in commercial systems or where tighter control is needed. They’re more stable over time but usually come at a higher cost.

Housing materials should match the water chemistry. Stainless steel or brass works in standard conditions. For saltwater or high-chlorine setups, epoxy coatings or thermoplastics handle corrosion better.

Sensor placement affects accuracy. Install in a locati on with steady water flow, such as a return line or heater outlet. Avoid areas where water may stagnate or where the sensor could be exposed to air during pump shutoff.

Key Takeaways

Accurate temperature sensing helps keep pool and spa systems stable, efficient, and easier to maintain. It reduces chemical use, extends equipment life, and keeps water conditions consistent.

EI Sensor provides thermistors and RTDs designed for long-term performance in demanding water environments. We work directly with OEMs and system designers to deliver standard and custom solutions that match real-world conditions .

Email us at sales@ei-sensor.com to get started on a sensor that fits your system. We’re here to help with selection, design input, or technical suppor t.

The Role of Precision Temperature Sensors in Medical Devices

Tue, 02 Dec 2025 20:59:51 GMT

Accurate temperature sensing is critical to the performance and safety of many medical devices. In applications where temperature stability directly impacts patient care or equipment reliability, the need for consistent and precise measurements becomes a design requirement.

EI Sensor Technologies provides sensors for medical devices that deliver dependable performance in demanding environments. These medical temperature sensors are built to ensure long-term accuracy, rapid response, and consistent output. OEMs rely on this level of control to meet regulatory standards and maintain device functionality over time.

The Importance of Precision Temperature Sensing in Medical Applications

Medical devices must operate within tight thermal tolerances, where even minor temperature fluctuations can impact performance or patient safety. Reliable sensing makes it possible to maintain these thresholds and support consistent operation.

Applications such as fluid warming, tissue diagnostics, and powered patient systems depend on precise temperature inputs. Thermistors and RTDs are widely used for their accuracy, responsiveness, and ability to perform in compact spaces. These sensors help maintain system stability under different loads and ambient conditions, contributing to device longevity and regulatory compliance.

Patient Monitoring Applications

Precise temperature measurement is essential in patient monitoring systems, where real-time data influences diagnosis and clinical response. High-performance sensors enable both routine checks and advanced monitoring to operate within required thresholds.

Non-Invasive Monitoring

Devices such as digital thermometers, wearable health patches, and surface probes rely on compact, fast-responding thermistors to track body temperature accurately. These sensors offer high sensitivity and are well-suited for early detection of fever or thermal irregularities.

Clinical Environments

In critical care settings such as ICUs, surgical units, and neonatal wards, monitoring systems operate continuously. Sensor reliability, thermal stability, and precise integration help maintain device accuracy and safeguard patient health.

In applications like catheter-based monitoring and intraoperative systems, sensors are embedded within devices that function inside the body. These components must deliver consistent readings over extended use while meeting biocompatibility and miniaturization requirements.

Sensor assemblies used in these environments often require specialized encapsulation materials and form factors that can withstand sterilization or prolonged exposure to fluids. Selection criteria may include thermal response time, insulation properties, and compatibility with catheter dimensions or biofeedback systems.

Invasive and Continuous Monitoring

Lab and Diagnostic Equipment

Laboratory and diagnostic devices rely on precise thermal management to operate reliably. Temperature sensors help control system stability, reduce measurement errors, and support consistent testing outcomes.

Sample Handling and Analysis

Instruments such as blood analyzers, centrifuges, and immunoassay systems operate within tightly controlled environments. Medical temperature sensors regulate fluid temperatures, incubation zones, and reagent storage. Accurate sensing improves test consistency and protects sample integrity.

These sensors also play a role in maintaining instrument calibration, allowing instruments to operate consistently across regulatory audits and quality control procedures .

Imaging and Diagnostic Devices

MRI, CT, and ultrasound systems use sensors to monitor internal temperatures and manage heat buildup in sensitive components. Maintaining thermal balance helps protect electronics, enhance image quality, and maintain safe conditions during patient use.

Integrated Control Systems

Many diagnostic platforms rely on automated thermal control. Thermistors and RTDs deliver the responsiveness and accuracy needed for stable closed-loop performance. Selection often depends on size, tolerance, and durability in high-use environments.

Sterilization and Disinfection Processes

Effective sterilization depends on precise thermal control. Temperature sensors are used to monitor, regulate, and verify thermal conditions across a range of disinfection methods.

Autoclaves and Steam Sterilizers

Steam sterilizers use high-pressure, high-temperature cycles to neutralize pathogens. Temperature sensors monitor internal chamber conditions to verify that required thermal thresholds are consistently reached and sustained throughout each cycle. Thermistors and RTDs are commonly integrated into chamber walls or probe assemblies to provide rapid, stable feedback during operation.

Chemical Sterilization and Disinfection Systems

Low-temperature sterilization methods using ethylene oxide or hydrogen peroxide gas also rely on accurate temperature monitoring. Sensors regulate the reaction environment and help maintain safe operating conditions, particularly when temperature-sensitive instruments are involved.

Washer-Disinfectors and High-Temperature Cleaning Units

Medical washers and disinfectors use heated water or solutions to clean surgical tools and reusable devices. Temperature sensors verify the effectiveness of the cleaning cycle by monitoring thermal levels in spray arms, tanks, or reservoirs. Reliable sensing helps facilities meet hygiene compliance standards while protecting device integrity.

Why EI Sensor Technologies is the Ideal Partner

Medical device manufacturers need sensor solutions that deliver consistent accuracy, integrate easily into complex systems, and meet application-specific requirements . EI Sensor Technologies offers a full range of thermistors, RTDs, and custom probe assemblies designed for use in healthcare environments.

With over 30 years of experience, the team works closely with OEMs to develop components that meet performance , space, and compliance goals. Whether the need is for a miniature thermistor in a wearable monitor or a robust RTD for high-temperature sterilization equipment, EI Sensor provides options tailored to meet unique design challenges.

Most projects require more than off-the-shelf parts. That’s why EI Sensor supports custom solutions, backed by engineering guidance, responsive service, and a focus on long-term reliability.

Let’s discuss your temperature sensing needs. Call or email us at sales@ei-sensor.com for engineering support or to request a quo te.

How to Choose the Right NTC Thermistor

Mon, 01 Dec 2025 16:00:26 GMT

Selecting the right NTC thermistor for an application is a critical step in ensuring accurate and reliable temperature measurement. These versatile sensors, also known as NTC temperature sensors, are widely used across industries such as HVAC-R, medical devices, industrial equipment, and appliances. However, with so many types and specifications available, finding the best match for specific needs can feel overwhelming.

Understanding the different types of NTC thermistors , along with key factors like temperature range, accuracy, and stability, can simplify the decision-making process .

Types of NTC Thermistors

NTC thermistors come in various forms, each designed to meet specific application needs. Understanding the distinctions between these types can help in selecting the right sensor for precise and reliable temperature measurement.

Glass Body / Encapsulated

Glass-body NTC thermistors are highly durable and suitable for environments where extreme temperature changes or harsh conditions are present. Encapsulation in glass ensures resistance to thermal shock and mechanical stress, making it ideal for industrial and automotive applications. These thermistors can operate within a wide temperature range, typically up to 300°C, offering exceptional long-term stability.

Epoxy Coated

Epoxy-coated NTC thermistors are versatile and cost-effective. They are commonly used in applications up to 150°C, and offer high accuracy solutions. The epoxy coating provides basic protection of the NTC element, making them a good choice for general-purpose applications in appliances, HVAC-R systems, and medical devices.

Surface Mount

Surface mount NTC thermistors are compact and designed for circuit board integration. They are ideal for applications where space is limited, such as modern electronics, wearable devices, and compact industrial controls. These thermistors are engineered for fast response times and high accuracy, allowing precise temperature monitoring in tight spaces.

Probe Assemblies

Probe assemblies combine NTC thermistors with protective housings and leads, making them suitable for customized applications. These assemblies are tailored for industries like food handling, medical equipment, and HVAC-R, where precise temperature sensing is essential. With a variety of housing materials and designs, probe assemblies offer flexibility to meet specific environmental or operational demands.

Key Considerations to Make When Choosing an NTC Thermistor

Choosing the best NTC thermistor requires careful evaluation of factors such as temperature range, accuracy, and stability to maintain reliable performance.

Temperature Range

Temperature range is one of the most important factors when choosing an NTC thermistor. Depending on the application, the sensor must operate effectively within specific temperature limits. For example:

RTDs are ideal for applications with extreme temperatures (-200°C to +850°C).
NTC thermistors , typically suitable for ranges between -55°C to +300°C, excel in high-sensitivity applications within more moderate temperature conditions'

Applications like HVAC systems or medical devices may require a thermistor that performs consistently in bot h controlled and fluctuating environments.

Accuracy

Accuracy is critical in applications requiring precise temperature control, such as medical devices or industrial systems. An NTC thermistor can offer greater accuracy but may come at a higher cost. Evaluating the acceptable margin of error for the application helps in balancing performance and budgetary requirements.

Stability

Thermal and electrical stability are essential for long-term performance. Inconsistent readings or drifting resistance values over time can compromise reliability. Glass body NTC thermistors, for example, offer superior stability, making them ideal for demanding environments with frequent temperature fluctuations.

Packaging

The physical packaging of the thermistor should align with the application's requirements. Consider whether a surface mount, epoxy-coated, or probe assembly type is better suited for installation, handling, and durability in the specific environment.

Custom packaging options, such as thermistors integrated with specialized connectors or housings, can further enhance ease of use and compatibility with existing systems.

Additional Considerations

In addition to the primary factors like temperature range, accuracy, and stability, there are several other considerations that play a crucial role in selecting the right NTC thermistor for an application.

Leads

The type and length of leads can impact how the thermistor is connected to a system. For instance:

Bare leads provide flexibility for custom installations but may require additional insulation.
Insulated leads offer protection in environments where exposure to moisture, vibration, or other conditions is a concern.

Choosing the appropriate lead configura tion ensures compatibility with the intended assembly and operating environment.

Coating

Coating material affects the durability and environmental resistance of the thermistor.

Epoxy coatings offer basic moisture resistance and are suitable for less demanding conditions.
Glass coatings provide superior protection against thermal shocks, mechanical stress, and harsh environments.

The right coating depends on the applic ation's exposure to external elements and required longevity. Applications exposed to saline environments, such as marine equipment, often require thermistors with specialized coatings for corrosion resistance.

R25 Values

The R25 value refers to the resistance of the thermistor at 25°C and is a key parameter for matching a thermistor to its intended use. A higher or lower R25 value can affect the sensitivity and operating range of the sensor. This characteristic must align with the application's specific requirements to achieve accurate temperature measurements.

Let’s Discuss Your Temperature Sensing Needs!

Finding the right NTC thermistor is essential for achieving accurate and reliable temperature measurements. Considering factors such as temperature range, accuracy, stability, and application-specific requirements, helps ensure optimal performance.

EI Sensor Technologies offers the expertise and innovative solutions needed to meet both standard and custom temperature sensing needs. Contact us at sales@ei-sensor.com to discuss your application or request a quote today !

How Thermistors are Boosting Electric Vehicle Efficiency

Tue, 25 Nov 2025 15:23:53 GMT

The Role of Thermistors in Electric Vehicles

As electric vehicles (EVs) continue to gain traction worldwide, efficient thermal management has become essential for optimizing performance and extending battery life. Thermistors, which are temperature-sensitive resistors , play a critical role in monitoring and regulating the temperature of various components within EVs. By providing accurate, responsive temperature measurements, thermistors help prevent overheating and maintain optimal conditions for key systems, from the battery pack to the motor.

This ability to accurately monitor and manage heat helps enhance electric vehicle efficiency, ensuring that energy use is optimized and components remain protected across a range of driving conditions.

Important Functions of Thermistors in EVs

Thermistors play several key roles in electric vehicles , contributing to reliable operation and overall efficiency. These functions include temperature monitoring, thermal management, and protection of critical components like the battery, motor, and power electronics. By keeping these systems operating within ideal temperature ranges, thermistors help boost electric vehicle efficiency and extend the lifespan of essential EV components.

Battery Management Systems

In electric vehicles, battery management systems (BMS) rely heavily on thermistors to monitor the temperature of battery cells. Maintaining optimal cell temperatures is critical for safety, performance, and battery lifespan. Thermistors in the BMS provide real-time data, allowing the system to adjust cooling or heating as needed to prevent overheating or excessive cold. This temperature control not only extends battery life but also enhances electric vehicle efficiency by optimizing energy use within the battery pack.

Charging System

Thermistors also play a vital role in the EV charging system by monitoring the temperature of battery cells during charging. Since charging generates heat, thermistors help make sure the cells do not overheat, which could degrade battery health or even pose safety risks. By providing precise temperature data, thermistors allow the charging system to adjust power flow to maintain safe conditions, improving charging efficiency and protecting the battery over time. This function is key to supporting overall electric vehicle efficiency and promoting reliable performance.

Electric Motor & Inverter Protection

Thermistors play an essential role in protecting the electric motor and inverter, both of which generate significant heat during operation. By monitoring temperatures in real-time, thermistors allow the system to reduce power or activate cooling when temperatures get too high, preventing overheating and potential damage. This thermal protection helps keep the motor and inverter performing reliably, enhancing the overall durability and performance of the EV’s powertrain.

Climate Controls

Thermistors are also crucial in managing the climate control systems within electric vehicles, ensuring passenger comfort without sacrificing energy efficiency. By accurately monitoring cabin and HVAC system temperatures, thermistors help regulate heating and cooling functions, adjusting energy use as needed to maintain optimal cabin conditions. This targeted temperature control conserves battery power, balancing comfort and efficiency to maximize the EV’s range.

Thermal Management

Thermal management is essential for maintaining consistent performance across an EV’s systems, especially under varying conditions. Thermistors provide precise temperature data that helps manage heat in the battery, motor, and electronics, enabling cooling systems to respond efficiently. This responsive thermal control prevents overheating, supports optimal operation, and reduces unnecessary energy consumption, all of which contribute to the overall efficiency and longevity of the vehicle.

Safety & Reliability

Thermistors enhance safety and reliability in electric vehicles by monitoring temperatures across critical systems, ensuring they operate within safe limits. Accurate temperature data allows systems to adjust or shut down if temperatures reach unsafe levels, preventing potential failures or hazards. This real-time monitoring not only protects vital components but also boosts the vehicle's overall dependability, giving drivers confidence in their EV’s performance and longevity.

Types of Thermistors Used in EVs

Electric vehicles rely on two primary types of thermistors: Negative Temperature Coefficient (NTC) and Positive Temperature Coefficient (PTC) thermistors. NTC thermistors, whose resistance decreases as temperature rises, are typically used in applications like battery management and motor protection, where precise, responsive temperature measurement is critical. PTC thermistors, which increase in resistance with rising temperature, are often used for safety features, such as overcurrent protection. Each type serves specific functions within the EV, contributing to efficient thermal management and system safety.

Negative Temperature Coefficient Thermistors (NTC)

NTC thermistors are widely used in EVs for their sensitivity and responsiveness to temperature changes. As the temperature rises, their resistance decreases, allowing for precise monitoring and control of components like battery cells and electric motors. This real-time responsiveness makes NTC thermistors ideal for applications where accurate temperature measurement is needed to prevent overheating and ensure stable performance across varying conditions.

Positive Temperature Coefficient Thermistors (PTC)

PTC thermistors increase in resistance as temperature rises, making them suitable for applications focused on safety and overcurrent protection in EVs. When temperatures exceed a certain threshold, the rising resistance of PTC thermistors effectively limits current flow, helping prevent overheating and potential damage. This characteristic makes PTC thermistors valuable for protecting sensitive electronics and making sure that systems remain within safe operational limits.

How Thermistors Will Continue to Shape the Future of Electric Cars

Thermistors are set to play an even more significant role in electric vehicle advancements, supporting innovations in fast charging, extended range, and improved safety systems. As EV technology evolves to meet higher demands for efficiency and performance, precise thermal management becomes increasingly essential. Thermistors provide the real-time data needed to enhance battery life, optimize power usage, and ensure safe operation under varying conditions. With thermistors driving these improvements, electric vehicles will continue to become more reliable and sustainable.

To learn more about thermistor solutions for electric vehicles, contact EI Sensor at sales@ei-sensor.com.

What is a Thermistor Probe?

Fri, 01 Aug 2025 15:35:58 GMT

A thermistor probe consists of a thermistor sensor element (bare chip, DO-35 Glass , epoxy coated or other element style) attached to extension lead wires and potted into a thermowell with thermally conductive epoxy or other potting material as dictated by the application. They are built to monitor, measure or control temperature, and provide accurate, reliable, fast, and stable thermal monitoring, at a cost-effective price.

Water heaters, HVAC controls , organ transport equipment, distillery equipment, battery chargers, coffee makers, electric vehicles, refrigerated supermarket displays…these are just some of the wide variety of applications in which thermistor probes have been proven invaluable for sensing temperature. In our everyday life, they are crucial for our comfort, safety and well-being.

Looking at the individual aspects of thermistor probes, we’ll start with the thermowell.

Thermowells (or probe housings) are made from materials such as Stainless Steel, Copper, Brass, Vinyl or Plastic. There are various mounting styles to choose from depending upon the needs of the application. Ring lugs, flag terminals, and pipe clip-on are commonly used for surface temperature sensing. Threaded such as a pipe plug or NPT with a tube, straight with a radius or pointed end, flanged thermowells with mounting holes are often used to measure fluid flow/fluid temperature in the Pool/Spa, Industrial or Medical industries or air temperature in the HVAC and Building Automation sector. EI Sensor has a wide variety of thermowell styles available, if you don’t see your required size or style, we are confident we can fulfill your needs so be sure to contact us to discuss further.

The extension lead wires on a thermistor probe assembly are typically insulated. Insulation types such as Teflon, PVC, Kynar or XLPE are commonly used. If warranted by the application, a higher temperature cable will be utilized. Single conductor, two conductor, solid or stranded, jacketed…there are many choices for your design. The length of the wire will be cut and stripped to your requirements.

Many thermistor probes are provided with terminals and connectors as dictated by the customer. Molex, TE, JST and Aptiv are just some of the many EI Sensor has supplied over the years. Don’t hesitate to let us know if we can help you with this value-add service.

The ability to customize a probe for a specific application is crucial to the end product. Our highly experienced design engineers will ask many questions to help narrow down the physical style as well as the electrical properties needed. Important characteristics we need to know include the size limitation(s) of the application, the operating temperature range, whether moisture will be present, the base resistance value and accuracy as well as if there are specific resistance vs temperature (RT) characteristics required. As the design develops, our engineers will offer a drawing or drawings of a thermistor probe showing the thermowell dimensions, lead wire details and the electrical characteristics. The customer can mark up the drawing if changes are needed and we will revise then resubmit for review.

Our website displays a subset of common thermistor probe styles. Our company prides itself on providing a customer with a solution that fits their needs so if don’t see your required style, contact us for further assistance at sales@ei-sensor.com . We will respond quickly to your inquiry.

EI Sensor Technologies Engineer Training

Wed, 30 Jul 2025 19:16:07 GMT

Introduction to Temperature Sensor Design

Aug 26, 2025 11:00 am - 12 pm

Join us for a focused 1-hour technical training session on EI Sensor Technologies' industry-leading NTC, PTC, a and RTD sensing solutions.

This session is designed for engineers and designers looking to:

Understand the capabilities of NTC, PTC, and RTD temperature sensors elements.
We will also cover custom probe design considerations, material types, cable consideration, and mounting options.
You will get get early insight into new products and application tips.
Ask questions directly to EI Sensor’s applications engineering team!

Contact:

EI Sales Inc.

EI Sensor Technologies

info@eisales.com

6142099260

Online

Event link

Why Attend?
Whether you're designing for industrial, medical, or consumer applications, EI Sensor Technologies offers precision, reliability, and integration support to take your product to the next level.

�� Ideal for:
Design Engineers · R&D Teams · Project Engineers · Systems Engineers

�� RSVP by August 21st

Temperature Sensor Terminology

Mon, 28 Jul 2025 21:00:13 GMT

Questions about the thermistor and RTD related technical terms found throughout the EI Sensor website? Never fear, EI Sensor’s application engineers to the rescue!

Our team has composed a list of the general terms and explanations for each to help on your journey into temperature sensors. If you are unsure about how the terms relate to your temperature sensing requirements, or you have a question that isn’t answered here, please don’t hesitate to contact us at sales@ei-sensor.com . We’d be happy to explain in further detail and assist with your needs. Thank you for visiting!

ACCURACY

Describes the variation between the measured value of a sensor versus that of its nominal specified characteristics. Expressed in degrees at one temperature or over a specified temperature range.

AMBIENT TEMPERATURE

The temperature of the environmental medium where the temperature sensor is immersed.

BETA VALUE

An arithmetic estimation of the resistance versus temperature characteristics of a thermistor, based upon two resistance versus temperature points. Beta is expressed in Kelvin (K).

DISSIPATION CONSTANT

The amount of applied power required to raise the body temperature of the sensor element by +1° in a specific environment. The dissipation constant is typically expressed in milliwatts per degree Celsius (mW/°C).

DRIFT

The gradual variation of a characteristic (typically zero-power resistance) of a sensor with respect to time.

INTERCHANGEABILITY ERROR

The maximum measurement error between two sensors, when substituted for one another to make the same measurement.

MAXIMUM TEMPERATURE RATING

The maximum body temperature at which the sensor will safely survive for an extended duration. The body temperature of the sensor can be influenced by internal heating, external heating or a combination of internal and external heating. It is recommended that this temperature rating never be exceeded.

MAXIMUM POWER RATING

The maximum power which a sensor will safely dissipate for an extended duration.

MAXIMUM STEADY-STATE CURRENT (Imax)

The maximum continuous steady-state current (Vrms or Vdc) that an inrush current limiting thermistor has the ability to pass. This value is typically determined based upon a maximum ambient operating temperature of +65°C.

NEGATIVE TEMPERATURE COEFFICIENT (NTC)

Describes a material whose zero-power resistance decreases with a corresponding increase in its body temperature.

POSITIVE TEMPERATURE COEFFICIENT (PTC)

Describes a material whose zero-power resistance increases with a corresponding increase in its body temperature.

REPEATABILITY

The capability of a sensor to provide identical readings, when subjected to duplicate conditions.

RESISTANCE AT MAXIMUM CURRENT
(R @ Imax)

The nominal resistance of an inrush current limiting thermistor when being subjected to a maximum steady-state current condition.

RESISTANCE RATIO

The ratio of a thermistor’s resistance versus temperature characteristics. This value is calculated between two specified zero-power resistance versus temperature points.

RESISTANCE VERSUS TEMPERATURE CHARACTERISTIC

Describes the relationship between the zero-power resistance of a thermistor and its body temperature. The best mathematical interpretation of a thermistor’s resistance versus temperature characteristics is the Steinhart-Hart equation.

ROHS

Restriction of Hazardous Substances. Also referred to as Directive 2002/95/EC.

SELF-HEATING

The effect of passing current through a sensor, which results in raising the body temperature of the sensor above that of the ambient temperature.

STABILITY

The capability of a sensor to maintain specified characteristics, after being exposed to specific conditions. These test conditions can be stated as electrical and/or environmental.

TEMPERATURE WATTAGE CHARACTERISTICS

The relationship at a specified ambient temperature between the body temperature of a thermistor and the applied steady-state wattage.

THERMAL TIME CONSTANT

The time required for a sensor to register a change (typically 63.2%) of the difference between its initial and final body temperatures, when exposed to a step-function change in temperature under zero-power conditions.

TOLERANCE

The spread between the permissible minimum and maximum values of a sensor. Generally used to describe a sensor’s resistance range or temperature error range.

ZERO-POWER RESISTANCE

The resistance value of a sensor, when measured at a specified temperature with zero-power dissipated through the sensor.

Quick Links to see the technical terms explained above in use:

What is an RTD?

Mon, 28 Jul 2025 20:33:30 GMT

An RTD (Resistance Temperature Detector) is a temperature sensor that exhibits an increase in resistance when subjected to an increase in temperature. RTDs are highly accurate sensor devices with low drift and excellent long term stability.

What types of RTDs are available?

There are two main types of resistance temperature detectors, thin-film and wire-wound.

Wire-Wound RTDs

Wire wound RTDs are built using a small diameter wire, typically platinum, which is wound into a coil and packaged inside a ceramic insulator. Larger extension wires are then spot welded to the platinum wire. Conversely, the small diameter wire can also be wound around the outside of a ceramic mandrill and coated with an insulating material such as glass with extension wires then being spot welded to the winding wires.

Thin Film RTD Elements

Thin film RTDs are made by depositing a thin layer of resistive material, typically platinum film, onto a ceramic substrate. A pattern is then etched onto the element, creating the electrical circuit. Platinum Thin-film RTDs (Pt-RTDs) offer a nearly linear temperature vs resistance relationship as well as very high accuracy over wide temperature ranges. The European standard DIN/IEC 60751 is considered the worldwide standard for platinum RTDs.

The three standard accuracy classes for these RTDs at 0°C are:

DIN Class A: ±0.15°C (IEC 60751 F 0.15)

DIN Class B: ±0.30°C (IEC 60751 F 0.3)

DIN Class C: ±0.60°C (IEC 60751 F 0.6)

Why Use an RTD over a Thermocouple?

RTDs are often preferred over thermocouples when accuracy, stability, and repeatability are paramount. Unlike thermocouples, RTDs provide highly precise temperature measurements with minimal drift over time, making them ideal for applications where consistent and reliable data is crucial. They are also less prone to electrical noise, ensuring stable readings in environments with electrical interference. Although RTDs have a narrower temperature range compared to thermocouples, their superior accuracy and long-term stability make them a preferred choice for critical applications like laboratory testing, industrial process control, and any scenario requiring precise temperature monitoring.

EI Sensor Technologies offers Platinum Thin Film RTDs . Capable of withstanding operating temperature from -200°C up to +850°C. Higher temperature ratings are available thru special order. Our standard resistance values for our leaded and surface mount devices are 100Ω, 500Ω and 1,000Ω with a TCR of 3,850 ppm/K (other values available) and we can supply just the sensing element or provide a full solution RTD probe assembly . Offered in a wide variety of thermowell configurations and sizes, the probe assemblies are well suited for temperature measurement in many industries such as White Goods, HVAC, Energy Management, Industrial Controls and Food Handling/Processing.

Our design engineers are available at sales@ei-sensor.com to assist with the selection of an RTD element or probe assembly for your unique application.

Applications of RTDs

RTDs (Resistance Temperature Detectors) are widely used in applications that require precise and reliable temperature measurements. They are commonly found in industrial environments such as chemical processing, food and beverage manufacturing , and power generation, where accurate temperature control is critical to safety and efficiency. RTDs are also used in HVAC systems for monitoring and regulating air temperatures, in automotive sensors for engine management, and in medical devices like incubators and patient monitoring systems. Their high accuracy, stability, and repeatability make them an ideal choice for any application where precise temperature data is essential.

PTC Thermistors, What They Are and How They Work

Thu, 24 Jul 2025 18:50:37 GMT

What is a PTC Thermistor?

Positive-temperature-coefficient (PTC) thermistors increase in resistance as their body temperature rises. There are two basic types of PTC thermistors. They’re either made of ceramic or silicon, and their material composition determines the thermistor’s electrical characteristics. The ceramic type typically exhibits a very high positive temperature coefficient of resistance at and above the switching point or “Curie temperature”. The silicon type of PTC thermistor typically exhibits a nearly linear positive coefficient of resistance of +0.7 percent per degree Celsius.

Thermistors are thermally sensitive resistors whose electrical resistance varies predictably with temperature. Thus, they’re ideal for monitoring and controlling temperature in household and industrial settings. EI Sensor produces various temperature sensors in standard and custom configurations, including NTC and PTC thermistors as well as RTDs (Resistance Temperature Detectors) and thermocouples.

What is a PTC Thermistor Probe?

PTC thermistors are often used in demanding environments, leading to their use as part of units called probes. For these, the thermistor is encased in a protective housing and connected to extension lead wires. The probe ensures the environmental protection of the PTC thermistor and provides for optimum performance in the intended field installation.

How Do PTC Thermistors Work?

Thermistors consist of ceramic or silicon bodies with known resistance curves. By connecting a thermistor to an electrical circuit, temperature variations are measured based on changes in the thermistor’s resistance. PTCs are used for temperature regulation and overcurrent protection as well as for resettable fuses.

Types of PTC Thermistors

Silicon PTC thermistors use silicon as the semiconducting material. They possess a near-linear positive temperature-resistance coefficient of +0.7 percent per degree Celsius. The switching-type PTC thermistor is made of ceramic materials. They show a nonlinear resistance-temperature curve, with resistance initially decreasing with heat. However, as the PTC reaches its critical “Curie” temperature, the resistance increases dramatically.

Typical Applications of PTC Thermistors

Applications for PTC thermistors include temperature sensing and control, overcurrent protection (such as resettable fuses), motor starters, liquid level sensing, temperature compensation, and self-regulated temperature heating elements.

Pros

PTC thermistors are highly sensitive, respond quickly, have self-regulating properties, and can operate over a wide range of temperatures.

EI Sensor offers a range of standard and custom temperature sensors, including PTC and NTC thermistors. If you have questions, contact us for help. We also support customers whose unique temperature measurement requirements require us to develop custom solutions.

What is a Thermistor?

Thu, 24 Jul 2025 18:49:34 GMT

How Does a Thermistor Measure Temperature?

Because thermistors have a very high and predictable change in their electrical resistance with temperature, simple circuitry can provide the user with accurate temperature measurements. Also, because of their high-temperature coefficient and unlike many other temperature sensors, lead wire length doesn’t significantly affect the accuracy of the measurement.

Thermistors are THERMally sensitive resISTORS whose electrical resistance varies predictably with their body temperature, making them ideal tools for monitoring and controlling temperature in numerous applications including household and industrial products. Thermistors are typically used in applications requiring accurate temperature measurements within the range of -55 to +300°C and are often used in demanding operational environments. The sensors can be provided encased in a probe assembly configuration, meaning they are mounted in a thermowell or protective housing made of metal or plastic to ensure they withstand the environmental stresses required by the application. Special insulated lead wires are offered as well.

EI Sensor offers a wide range of standard or off-the-shelf thermistors as well as custom designs to provide solutions to customers with unique requirements. If you have questions, click our handy list of key temperature sensor terminology or contact us .

The Two Types of Thermistors

Thermistors come in two types. Negative-temperature-coefficient (NTC) thermistors decrease in electrical resistance as their body temperature rises and positive-temperature-coefficient (PTC) thermistors increase in electrical resistance as their body temperature rises.

Negative Temperature Coefficient (NTC) Thermistors

Positive Temperature Coefficient (PTC) Thermistors

NTC Thermistors are made of sintered metal oxides. The precise composition of the materials as well as the manufacturing process determines the resistance vs temperature characteristics of the product. NTC thermistors are most useful in applications requiring precision temperature measurement and/or control and can withstand operating temperatures from -55°C to +300°C.

PTC thermistors increase their electrical resistance as the temperature increases. Two types of PTC thermistors are Switching PTCs which are non-linear ceramic sensors and Silicon PTCs which exhibit a nearly linear positive ~7,000 ppm temperature coefficient of resistance. Switching PTCs are produced using polycrystalline ceramic materials such as barium carbonate and titanium oxide while Silicon PTC thermistors rely on the bulk resistance properties of doped silicon.

Benefits

NTC (Negative Temperature Coefficient) thermistors are highly valued for their precision and efficiency in temperature measurement and control. Here are some key benefits:

High Sensitivity: NTC thermistors respond quickly to temperature changes, providing accurate readings essential for precise control in various applications.
Wide Temperature Range: They function effectively across a broad range of temperatures, making them versatile for many environments.
Cost-Effective: Compared to other temperature sensors, NTC thermistors offer an affordable solution without compromising performance.
Compact Size: Their small size allows them to be used in tight spaces, making them ideal for modern electronic devices.
Reliability: With robust and stable performance, NTC thermistors ensure consistent operation over time, reducing maintenance needs.

These attributes make NTC thermistors a preferred choice in applications like HVAC systems, automotive sensors, and household appliances.

These advantages make PTC thermistors an excellent choice for applications like motor protection, surge current limiting, and as heating elements in automotive and consumer electronics.

Benefits

PTC (Positive Temperature Coefficient) thermistors are widely used for their unique ability to increase resistance with rising temperatures, providing numerous benefits:

Overcurrent Protection: PTC thermistors act as self-resetting fuses, protecting circuits from overcurrent conditions without needing replacement.
Temperature Regulation: They are ideal for maintaining consistent temperatures in heating elements and thermal management systems.
High Reliability: PTC thermistors are durable and provide stable performance, ensuring reliable operation in critical applications.
Fast Response Time: Their quick response to temperature changes helps prevent damage in sensitive electronic components.
Easy Integration: With simple and compact designs, PTC thermistors can be easily incorporated into a wide range of electronic devices.

What are the Applications of PTC Thermistors?

PTC thermistors are most often used for self-resetting overcurrent protection in small DC motors and as self-regulating spot heaters. You will commonly find PTC thermistors in household appliances that generate heat, automobiles, and many other household and industrial applications.

What are the Ap plications of NTC Thermistors?

NTC thermistors are widely used in everyday life from HVAC applications such as room thermostats, pool and spa controls, air conditioners, and heating systems to appliances such as refrigerators, ovens, and washing machines. They’re also commonly used in aerospace applications. Due to their excellent accuracy as well as long-term reliability, NTC thermistors are the sensor of choice for temperature measurement and control.

NTC thermistors are often used in harsh environments, so EI Sensor offers thermistor probe assemblies that combine a thermowell or probe assembly as well as specialized lead wires appropriate for each application. Click to learn more about EI Sensor thermistor probes .

Types of Temperature Sensors

Mon, 02 Jun 2025 14:55:06 GMT

What is a Temperature Sensor?

Temperature sensors measure and quantify temperature in materials and internal or external environments. The science behind how temperature sensors typically work involves resistance changes in metals or metal oxides and voltages generated between dissimilar metals. Specific types of temperature sensors exist to accommodate the wide category of temperature measurements required. When sensors detect temperature changes, they convert this detection into electrical signals that are analyzed by systems or instruments intended to control, monitor, or log data being sent by a temperature sensor.

For example, temperature sensors monitor and regulate the temperature of modern household appliances such as ovens, cooktops, and clothes dryers. On the other extreme, in aerospace applications, temperature sensors regulate the environmental temperature of spacecraft, astronauts’ spacesuits…and everything in between.

The precise sensing capabilities provided by temperature sensors make them indispensable for our safety and comfort.

Applications of Temperature Sensors

Industrial processes , medical devices , monitoring systems, food production , home appliances (refrigerators, air conditioners, ovens), and climate control systems are just a few of the thousands of applications that depend exclusively on the different types of temperature sensors.

Pharmaceutical companies rely heavily on temperature sensors to produce safe and effective medications. In addition, storing and transporting vaccines demands rigorous temperature control to avoid rendering vaccines defective. During the COVID-19 pandemic, temperature sensors were used to maintain the cold chain for COVID-19 vaccines being shipped across the country.

Negative Temperature Coefficient (NTC) Thermistors

NTC thermistors decrease in electrical resistance as temperatures rise. They’re primarily used for temperature measurement, control, and compensation as well as for inrush current limiting applications to suppress initial current surges in electronic circuitry. NTC thermistors are typically suitable for use over the temperature range from -55C to +300C, however, some special designs are usable beyond this temperature range. Because most temperature measurements are made within this temperature range and because of their low cost, their excellent accuracy, and their long-term stability, thermistors are the sensors of choice over other sensors.

NTC thermistor uses include digital thermometers, HVAC/R systems, hydrogen fuel cells, appliances, and fluid/gas flow measurement just to name a few.

Examples of additional NTC thermistor applications include:

Automobile passenger environmental control
Rechargeable battery charging
Audio amplifiers
Respiratory devices
Welding equipment
Thermostats
Pool/Spa controls
Food storage systems
Smoke and Fire detectors

Positive Temperature Coefficient (PTC) Thermistor

PTC thermistors increase in electrical resistance as temperatures rise and are often used to avoid product overheating or overcurrent conditions. These temperature sensors are used in applications where a rapid resistance increase is essential once temperatures reach a predetermined threshold.

Examples of PTC applications include:

Self-regulating heaters
Electronic ballasts
Heating elements
Rechargeable battery over temperature protection
LED lighting systems
EV automotive batteries
Charging systems for electronic devices
Small motor over current protection
Wind turbines
Solar power systems

Thermocouples are temperature sensors that generate a minute voltage that varies depending on their body temperature. Thermocouples typically consist of two dissimilar metal wires joined at a junction. They generate an EMF (millivoltage) that is a function of the temperature of the junction. They are capable of extremely high-temperature operation, as high as 1700C.

Thermocouples

Resistance Temperature Detectors (RTD)

RTDs are passive transducers that present a precise and nearly linear resistance change corresponding to temperature changes. Although more expensive than thermistors, when necessary, they provide a wider temperature range of measurement capabilities…. up to 1,000C. RTDs are manufactured using various metals as the sensing element, however, because platinum’s temperature versus resistance properties are the most stable, uniform, and versatile, platinum RTDs are predominantly accepted as an interpolation standard for the International Practical Temperature Scale from near absolute zero to the melting point of antimony (1666.9 degrees F).

Examples of RTD applications include:

Industrial boilers
Air and gas temperature measurement
Food handling and processing
HVAC systems
Self-cleaning ovens
Cooktops
Deep fryers

The Most Common Types of Temperature Sensors

WHY EI SENSOR?

Obtaining reliable, accurate readings from high-quality temperature sensors is essential for optimizing the efficiency and safety of manufactured goods in various industries. At EI Sensor, we offer different types of temperature sensors to precisely sense temperature in fluids, gasses, and machinery components. Medical equipment especially depends on accurate temperature sensors to support patient safety and ensure that the equipment maintains accuracy as well as optimal performance over time.

Our precision-engineered temperature sensors are built to meet or exceed the specifications’ parameters for durability and accuracy. Our knowledge and resources enable us to provide optimum off-the-shelf or built-to-print temperature sensor designs.

Looking for a Temperature Sensor? Get in Touch with us Today!

At EI Sensor, our precision-engineered temperature sensors are designed to exceed our customers’ demands for durability, versatility, and accuracy. With over 30 years of experience in constructing superior temperature sensors, EI Sensor is a global provider of RTDs, NTC, and PTC thermistors for all types of industries. Let’s discuss your temperature-sensing needs! Contact us today!

Thermocouples vs. Thermistors: Key Differences

Mon, 02 Jun 2025 14:35:36 GMT

Although both components are temperature sensors, they operate on different physics principles. Thermistors made of semiconductor materials are ideal for applications demanding precise measurements within the temperature range of about -55C to 300C. Thermocouples are designed to measure a broader range of temperatures by generating a millivoltage relative to their body temperature.

With over 100 years of collective experience, the EI Sensor team provides customers with precision thermistors, technical expertise for resolving complex issues, and practical business strategies to help improve and streamline their operations. Call or email us today for more information about our services regarding your thermistor needs.

What is a Thermistor?

NTC Thermistors and thermistor probes detect temperature over their operational temperature range and provide a corresponding precise resistance to current flow corresponding to their body temperature.

(NTC) or Negative Temperature Coefficient thermistors decrease in electrical resistance when their body temperatures increase, while PTC thermistors increase their resistance when temperatures rise.

In common electrical circuits, a fixed resistor is placed in series with the thermistor, and a voltage source is applied, forming a voltage divider. When a thermistor’s resistance detects a temperature change, the voltage across the thermistor measured by the circuit also changes. Voltage fluctuations signal to the control system that a temperature variation is occurring.

Applications of Thermistors

EI Sensor's Selection of Thermistors

EI Sensor Technologies is a global leader in providing thermistors and thermistor probe assemblies with resistance values ranging from 100 ohms to 5M ohms and with temperature accuracies as precise as plus or minus 0.05C over a wide temperature range.

Glass Body Thermistors

We offer high-temperature glass body thermistors in both axial and radial-leaded designs. Reaching maximum operating temperatures of +300°C, they offer excellent stability and reliability in long-term challenging environments.

Surface Mount Thermistors

Our surface-mount thermistors include End-Banded Chip thermistors and the high-temperature MELF in various sizes. Ensuring reliable precision, rapid response times, and resilience in extreme conditions, EI Sensor’s surface mount thermistors are ideal for measuring and controlling temperature changes within concentrated areas of electronic circuits.

Epoxy Coated Thermistors

EI Sensor’s epoxy-coated thermistors are equipped with lead wires insulated with Teflon or Kynar and are also available with uninsulated lead wires. In addition, our interchangeable epoxy-coated thermistors assure precise accuracies over wide temperature ranges.

The epoxy coating we use on our thermistors provides numerous benefits, such as high thermal conductivity, protection against abrasion and mechanical damage as well as resistance to moisture contamination.

What is a Thermocouple?

Consisting of two different but specific metals corresponding to their desired properties, thermocouples provide temperature-sensing information by generating a millivoltage corresponding to the junction temperatures. When the junction is cooled or heated, the voltage changes corresponding to the appropriate temperature-voltage reference table.

Applications of Thermocouples

Food processing : Thermocouples may be used for monitoring temperature during various phases of food processing

Power generation : detects temperature changes within turbines, power plant exhaust systems, and industrial boilers

Metal forging and melting : Thermocouples are used in metalworking due to their ability to withstand higher temperatures

Auto engines : monitors engine torque and exhaust gas temperatures

Thermocouple vs Thermistor: Advantages and Disadvantages

Power Source for Thermocouples

When the junction of two different metals senses temperature fluctuations, the thermocouple generates a millivoltage sensed by a sophisticated data capture device or millivolt meter.

Power Source for Thermistors

Resistance changes are typically measured by applying an external voltage to a thermistor resistor series network and then measuring the voltage drop at the center point. Thermistors have a resistance versus temperature relationship that can be expressed by an equation or by a simple lookup table.

Accuracy of Thermocouples

Depending on the thermocouple type and operating conditions, thermocouples can attain an accuracy level of ± 1.8°F.

Accuracy of Thermistors

Thermistors can be provided with accuracies as accurate as plus or minus 0.05 degree Celsius making them more suitable when high precision is required by the application.

Thermocouple Stability

Thermocouples can drift over time due to wear and tear, high temperatures, and harsh environmental conditions. They are also susceptible to electromagnetic interference that can affect accuracy and premature stability.

Thermistor Stability

Consistently providing precise temperature measurements and long-term stability, thermistors are highly sensitive to temperature fluctuations. They can be produced to exhibit minimal drift over time. Thermistors are less impacted by electrical noise than thermocouples and deliver rapid responses to dynamic processes.

Contact EI Sensor for Immediate Assistance in Resolving Your Temperature Sensor Problems

We have built a stellar reputation for providing unparalleled precision and reliability with our standard and customized thermistors. Contact us today!

NTC Thermistors: What They Are and How They Work

Mon, 02 Jun 2025 13:49:59 GMT

Thermistors are thermally sensitive resistors whose electrical resistance varies predictably with temperature. Thus, they are ideal for monitoring and controlling temperature in household and industrial settings. EI Sensor produces various temperature sensors in standard and custom configurations, including NTC and PTC thermistors, RTDs, and thermocouples.

What is an NTC Thermistor?

There are two thermistor types. Negative-temperature-coefficient (NTC) thermistors exhibit less resistance at higher temperatures, while positive-temperature-coefficient (PTC) thermistors show more resistance at higher temperatures. NTC thermistors are powdered metal oxides, and their composition determines the thermistor’s electrical characteristics. NTC thermistor sensors have a non-linear temperature curve and withstand temperatures from -55°C to +300°C.

What is an NTC Thermistor Probe?

Because NTC thermistors are often used in demanding environments, they are commonly used as part of units called probes. In these, the thermistor is encased in a protective housing and connected to lead wires. The probe ensures the protection of the NTC thermistor and provides for easier field installation.

NTC Thermistors vs Thermistor Probes

NTC thermistors are sensors, but their use in demanding environments requires them to be configured as part of thermistor probes . These probes combine the thermistor and lead wires mounted in a metal or plastic thermowell or protective housing.

How Do NTC Thermistors Work?

Thermistors are powdered metal oxides or ceramics with known resistance curves. By connecting a thermistor to an electrical circuit, temperature variations are measured based on changes in the thermistor’s resistance.

Types of NTC Thermistors

Five common types of NTC thermistors differ in robustness: glass-encapsulated, glass bead, epoxy-coated, surface mount, disc, and chip. The glass-encapsulated versions have axial lead wires and are suitable for harsh environments because the glass capsule protects them from chemicals, moisture, and physical damage.

Glass Bead thermistors feature a radial lead wire with fast response times and, like the axial lead version, they are suitable for harsh environments. Epoxy thermistors have uninsulated or insulated lead wires, with excellent long-term reliability. Surface-mount thermistors come in various configurations and work well in non-caustic environments. Disc and chip-type thermistors are the bare-bones version, which have excellent thermal stability. Discs generally have a slower response time than the chip style.

Typical Applications of NTC Thermistors

NTC thermistor applications include temperature measurement, control, and compensation applications, such as temperature sensing and control, current control, inrush current limiters, and overheating prevention.

NTC thermistors come in various configurations, some more suited for one environment or application than another.

Pros & Cons of NTC Thermistors

Pros

NTC thermistors exhibit high sensitivity and quick response in operation, yet are small and inexpensive relative to other temperature sensors.

Cons

The resistance of NTC thermistors is non-linear, so complex equations are needed for accurate readings.

EI Sensor offers a range of standard and custom temperature sensors, including NTC thermistors. If you have questions, contact us ; we’ll gladly help. We also support customers whose unique temperature measurement requirements require us to develop custom solutions.