What is a PTC thermistor?

In this article from our support we will present the operating principles of these thermistors and detail the different types of existing sensors. The operating principle is as follows. The PTC thermistor (positive temperature coeficiant) is a thermally sensitive semiconductor resistor, the resistance increases with increasing temperature.

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There are two types of PTC thermistor probes

- Linear PTC thermistor probes for temperature measurement
- Non-linear PTC thermistor probes for monitoring temperature threshold overruns


The linear PTC thermistor probe:

Resistors with silicon have a fairly uniform positive temperature coefficient (around + 0,77% / C) over most of their operating range, often used for temperature measurement and temperature compensation.

The non-linear PTC thermistor probe:

Made of doped polycrystalline ceramic based on barium titanite (major BaTio3 material). The resistance increases strongly at the Curie temperature. Used for :

- overload protection

- protection against overcurrents

- protection against overheating

- self-regulating heating

- starting the engine

- progressive lighting start-up, etc.

Silicon PTC thermistor temperature sensorPTC thermistor

GUILCOR silicone linear PTC thermistors. These temperature sensors are encapsulated in glass with inside an element equivalent to the following elements KTY84 KTY83 KTY81, R25 600, 1000, 2000 ohm. As resistance increases with increasing temperature in linearity, silicon temperature sensors exhibit fail-safe operation when a system overheats. In addition, silicon is inherently stable with a very long operational life, widely applied in the detection and control of temperature in drives and motors.

PTC thermistor temperature sensor for motor protection

These PTC thermistorsSingle and triple PTC thermistor have a resistance that increases exponentially as the Curie point approaches. They are suitable for monitoring temperature limits.

For example:

- To turn on a fan when a particular temperature is reached.

- For the detection of overheating of windings in electric motors, coils, transformers, equipment, machines, etc.


Looking for information about linear and non-linear PTC probes? Go directly to the dedicated page!