How do you test a faulty thermistor?

How do you test a faulty thermistor?

When you apply heat to the body of a thermistor, its resistance should begin to steadily decline within seconds after heat is applied. If the NTC thermistor follows this behavior, then it is good. If it does not, it is faulty and should be discarded.

Is there a positive and negative on a thermistor?

There are two types of thermistors: Negative Temperature Coefficient (NTC) and Positive Temperature Coefficient (PTC). With an NTC thermistor, when the temperature increases, resistance decreases. Conversely, when temperature decreases, resistance increases.

Should a thermistor have continuity?

The thermistor that you are asking about is a negative temperature coefficient sensor. It should always measure continuity. The resistance of this sensor is used by the control board to determine temperature. At room temperature, the resistance of the thermistor is normally about 12K ohms (12,000 ohms).

How do you bypass a thermistor?

-Disconnect the thermister, and apply a meter to it and read initial resistance value. -You can try pinching the thermister between thumb and forefinger to increase the temp and read the change in resistance. That’ll help give a range of resistance.

How do you test a thermistor with a multimeter?

Connect the multimeter terminals to the thermistor leads. Polarity is not an issue here. Now heat the thermistor by moving your heated soldering iron tip to it. Now you can see the multimeter reading smoothly increases or decreases depending on whether the thermistor under test is PTC or NTC.

Should thermistor have continuity?

How do you test the continuity of a thermistor?

Heat the soldering iron. Heat the thermistor by moving your heated soldering iron tip to it. Note the multimeter reading as you are applying this heat. A properly functioning positive temperature coefficient thermistor will show a smooth and steady increase in the multimeter resistance reading.

How do you find the value of thermistor?

Thermistor Response to Temperature As with any resistor, you can use the ohmmeter setting on your multimeter to measure thermistor resistance. The resistance value displayed on your multimeter should correspond to the ambient temperature near the thermistor. The resistance will change in response to temperature change.

How to test an NTC thermistor?

How to Test an NTC Thermistor. An NTC thermistor, again, is a thermistors whose resistance decreases when the temperature it is exposed to increases. We will check this characteristic to see whether it behaves accordingly. First, before applying any heat to the thermistor, check its rated value.

How to test a PTC thermistor with an ohmmeter?

First check, with an ohmmeter, the thermistor without any heat applied. With a PTC thermistor at room temperature or below, the thermistor should measure a very low resistance. Now apply heat, just like before, to the thermistor’s body. The resistance of the PTC thermistor should gradually and steadily rise, within seconds of being applied.

What should the resistance value of a thermistor be?

Before any heat is applied to the thermistor, its resistance value should be very closely near its rated resistance value. So, for example, if we are testing a 10KΩ thermistor, before we apply any heat, its resistance value should be very close to 10KΩ. If you’re in a relatively warm room, it may be about 9.3KΩ.

How can you tell if a thermistor is good or bad?

If you’re in a relatively warm room, it may be about 9.3KΩ. If you’re in a colder area, it will be at a higher value. This is the first preliminary test to check whether a thermistor is good. If it is near its rated resistance value, then so far, it is good.