During the testing process, use the ohmmeter setting of the multimeter (determine the gear based on the specified resistance value, usually R×1 gear), and the specific operation can be divided into two steps: Firstly, conduct a normal temperature test (the indoor temperature is close to 25℃). Use the vise grips instead of the test probes to clamp the two pins of the PTC thermistor and measure its actual resistance value. Compare it with the nominal resistance value. If the difference is within ±2Ω, it is considered normal. If the actual resistance value differs greatly from the nominal resistance value, it indicates poor performance or damage. Secondly, conduct a heating test. Based on the normal test results, you can perform the second test - the heating test. Place a heat source (such as an electric soldering iron) close to the thermistor to heat it. Observe the reading on the multimeter. If you see that the reading changes with the increase in temperature, this indicates that the resistance value is gradually changing (the resistance value of a negative temperature coefficient thermistor NTC will decrease, and the resistance value of a positive temperature coefficient thermistor PTC will increase). When the resistance value changes to a certain value, the displayed data will gradually stabilize, indicating that the thermistor is normal. If the resistance value does not change, it indicates poor performance and cannot be used any longer.

When conducting the test, please pay attention to the following points:

(Rt) was measured by the manufacturer under an environmental temperature of 25℃. Therefore, when measuring Rt with a multimeter, it is also necessary to conduct the measurement under an environment with a temperature close to 25℃ to ensure the reliability of the test.

(2) The measured power must not exceed the specified value to prevent measurement errors caused by the thermal effect of the current.

(3) Pay attention to correct operation. During the test, do not hold the thermistor body with your hands to avoid the influence of human body temperature on the test results.

(4) Be careful not to place the heat source too close to the PTC thermistor or to have it in direct contact with the thermistor, as this could cause it to be damaged by heat.

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