Simple measurement method of NTC thermistor

NTC thermistor is a commonly used type of thermistor, and has certain applications in many fields. When we use NTC thermistors, we need to master the measurement method of NTC thermistors. Today, the editor will introduce the simple measurement method of NTC thermistors to you in detail, hoping to help you.

1. Purpose:

In the absence of dedicated NTC thermistor test instruments, meters and measuring fixtures, but the NTC thermistor needs to be measured, this method provides a simple test method. Although it cannot achieve professional level accuracy, it can roughly measure the resistance and accuracy of the thermistor.

2. Measuring tools and materials:

1. Four-and-a-half-digit multimeter: two.

2. Test fixture: one.

3. ± 0.1℃ thermometer: one.

4. Stainless steel alligator clips: one pair.

3. Measurement methods and steps:

1. First, use air conditioning to control the room temperature at 25±0.1℃.

2. Place the thermometer in the room to monitor the indoor temperature.

3. Connect a pair of alligator clips to a pair of multimeter probe test terminals.

4. Clip the two leads of a standard thermistor on the alligator clips, insert the other end of the multimeter pen into the multimeter, turn on the multimeter and switch it to the appropriate resistance measurement position. The multimeter will then display the resistance of the thermistor at room temperature. (Note: The nominal resistance accuracy is within ±0.1%, and the B value accuracy is ±1%)

5. Place the alligator clip near the thermometer. This multimeter is used to monitor temperature changes in the room.

6. When the multimeter display value monitoring the room temperature is relatively stable, it means that the room temperature is relatively stable. At this time, the resistance of the indoor constant temperature can be tested. If the resistance value and accuracy of the thermistor used for monitoring on the crocodile clip are the same as the resistance value and accuracy of the thermistor to be tested, comparative measurement can be performed.

7. The thermistor to be tested can be judged as a qualified product based on the standard resistance value within the range of ±5% tested at room temperature.

4. Notes:

1. The indoor temperature change should be controlled within the range of 25±1℃. (When measuring, be sure to close the doors and windows, reduce air flow, and avoid people entering and leaving the room and walking back and forth).

2. When the constant temperature cannot achieve the control accuracy, a thermistor with the same resistance value and accuracy can be used as the room temperature monitoring resistor for comparative measurement.

3. The two multimeters should be calibrated accurately before measurement, and at least the consistency of the two meters should be checked.

4. The thermistor to be tested should be kept at a constant temperature for no less than 30 minutes at room temperature. If the product to be tested has been powered on and used, please leave it for 12 hours before testing.

5. The thermometer, monitoring thermistor, and resistor to be measured should be placed in the same position indoors to ensure accurate measurement.

6. When testing thermistors, the operator's hands should be kept at a certain distance from the thermistor as much as possible to avoid measurement errors caused by human body temperature.