Thermistors are temperature-sensing elements made of semiconductor material that has been sintered in order to display large changes in resistance in proportion to small changes in temperature.
Typical Applications Include:
- Temperature Compensation
- Voltage Regulation
- Circuit Protection
- Volume Control
- Time Delay
Thermistor Application Notes Summaries
- What is an NTC Thermistor
Summary: Explains what an NTC thermistor is and its capabilities as a temperature sensor. Ametherm’s NTC thermistors and probes are described, as well as the terminology used.
- NTC Thermistors – Temperature Measurement With Wheatstone Bridge
Summary: The Wheatstone Bridge is one of the easiest ways to measure temperature and explains how it is calculated using a specific example with certain variables. A chart of temperature versus volts is also provided.
- NTC Thermistors – The Basics
Summary: Explains the fundamentals regarding NTC thermistors, and commercial and military grade NTC thermistors.
- Applications for NTC Thermistor Probes
Summary: Three broad types of temperature measurement applications are discussed: (i) surface temperature, (ii) air and gas and (iii) liquid, but other applications are also possible, with different configuration combinations.
- Reliability Of A Thermistor
Summary: Products that contain thermistors usually carry a warranty. Find out how to determine the reliability of a thermistor in that product by doing a calculation. The equation – mean time before failure or MTBF of a thermistor – is demonstrated.
- NTC Thermistors – Accurate Measurements for NTC Thermistors
Summary: In using NTC thermistors to obtain accurate measurements, a phenomenon called “immersion stem effect” can occur. This article defines it and how it can be eliminated.
- NTC Thermistors – Calculate Beta Value For NTC Thermistors
Summary: Explains why the beta value, although often used, is not as accurate as using the Steinhart and Hart equation. The Steinhart and Hart equation uses three temperatures over a given range.
- NTC Thermistors – Power Dissipation for Temperature Detection Circuits
Summary: Calculating power dissipation can lead to errors, causing an inaccurate correlation between voltage reading and temperature. One solution is to use a bridge diagram which has a linear voltage-temperature characteristic, as opposed to using the temperature-rsistance curve which is non-linear and much harder to use.
- NTC Thermistors – Steinhart and Hart Equation
Summary: This equation is arguably the best to use when determining the resistance temperature relationship of NTC thermistors and NTC probe assemblies, given that the equation uses three temperatures. This article tells you which equation to use in your particular application.
- NTC Thermistor – Calculating the Temperature Coefficient of a Thermistor
Summary: This article provides you with an equation you can use to calculate a thermistor’s temperature coefficient. The temperature coefficient is the change that occurs in the resistance with a change in temperature. A useful and frequent customer example is provided.
- NTC Thermistors – Temperature Compensation Circuits
Summary: Metals like coils and solenoids often present problems involving temperature compensation. In an automotive application, you can minimize this problem by using a total resistance equation and a linearization equation. A step-by-step calculation will guide you.
- How to Select and Use an NTC Thermistor
Summary: Provides the key factors to consider when choosing a thermistor: (i) size and type (ii) thermistor features (iii) application or intended use (iv) resistance temperature curves (v) tolerance limits (vi) interchangeability and (vii) calibration. This article also briefly explains linear response elements versus thermistor probes.
- Selecting NTC Thermistors
Summary: Type and size of thermistor, resistance-temperature curves, nominal resistance value, resistance tolerance and beta tolerance are few of the things to consider before deciding which thermistor is the most appropriate for your needs.