Briefly talk about the fault detection of thermistors:
(1) First, observe the appearance of the thermistor. The potentiometer or thermistor must be clearly marked, the solder or pin shall be free of rust, the rotating shaft shall rotate flexibly, and the tightness shall be appropriate. The handle shall be smooth when rotating, and there shall be no mechanical noise and shaking.
(2) Gently shake the potentiometer pad or the pin of the thermistor by hand, and there should be no looseness.
(3) Set the resistance gear of the multimeter to the appropriate range, and then conduct ohmic zero adjustment. Use two probes (positive and negative) to connect with the pins at both ends of the resistor, so that the actual resistance value can be measured. Finally, compare the test value with the nominal value of the resistor, so as to judge whether the potentiometer or thermistor is in good condition. If the pointer of the multimeter does not move, it indicates that the internal resistor is disconnected.
(4) The center pin of potentiometer or thermistor is connected with its internal movable contact. Connect the center pin and any other pin with the two probes of the multimeter, and then slowly rotate the shaft handle. The pointer of the meter should move smoothly. If the pointer jumps or drops, it indicates that the movable contact point and the resistor are in poor contact.