NTC Thermistor Chips & How They Are Made

A temperature sensor may look simple from the outside, but its performance starts at the material level. For OEMs, differences in resistance, response, stability, size, and/or operating range can affect how well a sensor performs in an application.

Those characteristics begin to take shape long before a thermistor reaches a finished probe assembly. The material composition selected for an NTC thermistor chip, as well as the manufacturing processes involved, influence its electrical properties and stability characteristics.

Manufacturing begins by carefully selecting, blending and processing metal oxide powders according to the desired electrical characteristics. The blended materials are formed into a ceramic body, and then fired at high temperatures through a process called sintering. The sintering process turns the metal oxide powders into a true ceramic.

After sintering, the resulting ceramic material is processed into individual chips. Electrodes are applied to the chip to provide an electrical contact. The electrodes may be applied before or after the ceramic material is processed into individual chips. The finished thermistor chips can then be tested and sorted according to their specified resistance characteristics.

An NTC thermistor chip is often incorporated into a finished temperature probe assembly. The chip can be attached to lead wires, encapsulated, and/or placed into a probe housing designed for the application. These added components help protect the sensing element and allow it to be installed into a particular application.

The probe design can influence response time, durability, moisture resistance capability and installation/mounting options. EI Sensor develops thermistor probe assemblies for OEM applications across HVAC-R, building automation, medical equipment, appliances, food handling and processing, and industrial systems. Custom designs can address specific size, mounting, electrical, and environmental requirements.

Choosing an NTC thermistor starts by considering the conditions that the sensor will encounter in the intended application. The final design should take into consideration the operating temperature range, nominal base resistance value, resistance versus temperature curve, temperature accuracy, size requirements, as well as other electrical and environmental requirements.

Knowing the environment that the sensor will be exposed to in the intended application is important. Exposure to moisture, vibration, chemicals, or repeated temperature cycling can influence how the sensor assembly is designed and manufactured.

The best selection of a thermistor is often a custom configuration rather than a standard component.

EI Sensor brings more than 30 years of temperature sensing experience to OEM projects. Our team applies that knowledge to standard and custom NTC thermistors and probe assemblies, including solutions for applications that require unique configurations.

Customers can work directly with an experienced team focused on practical technical support, consistent quality, and solutions that make their jobs easier.

Need engineering assistance or a quote for an NTC thermistor solution? Email sales@ei-sensor.com to discuss your project.