How to detect thermistors?

Last Update Time: 2019-06-15 17:03:27

The way to detect whether it's NTC or PTC.

There are two main types of thermistors:


1. A negative temperature coefficient thermistor (NTC) with a decrease in temperature rise resistance.



2. The positive temperature coefficient thermistor (PTC) with the increase of temperature rising resistance.



First, the common methods of detecting and judging.

Thermistors can be made into a variety of temperature sensors, to detect the temperature of coolant temperature sensor as an example, whether NTC or PTC sensor types of methods are as follows.


(1). The resistance between two terminals of coolant temperature sensor and its shell is measured by universal meter el


(2). Place the coolant temperature sensor in a b ectric barrier, and the resistance value should be infinity.eaker containing water. Heat the water in the beaker with an electric heater, as shown in figure 1.


(3). NTC thermistor sensor should conform to the resistance value of the characteristic curve shown in fig.2. Otherwise, if the resistance value changes with temperature, the resistance between the two sub-units of the sensor should be measured by the universal meter electric barrier. If the sensor is NTC thermistor sensor, it should conform to the resistance value of the characteristic curve shown in figure 4.

This indicates that the detected temperature sensor has bad characteristics or has been damaged.


Second, the method of judging whether it is NTC or PTC.

In the above detection, if the measured thermistor resistance decreases in inverse proportion with the increase of temperature, then the tested thermistor is a negative temperature coefficient thermistor, or NTC for short. On the contrary, when the water temperature increases above a certain temperature, the value of resistance increases sharply, then the thermistor being detected is a positive temperature coefficient thermistor, or PTC for short.