How to detect micro potentiometers?

Before detecting the micro potentiometer, the rotating handle can be turned to check whether the rotation of the shank is smooth, whether the switch is flexible, whether the "click" sound is clear and brittle when the switch is turned on and off, and listen to the sound of friction between the internal contact point of the potentiometer and the resistor. If there is a "rustling" sound, indicating that the quality is not good, after confirmation, and then use a multimeter to check it.

1. The detection method of nominal resistance value of potentiometer.

The schematic diagram of potentiometer nominal resistance detection is shown in fig. 1. The resistance measured at both ends of the 1 and 3 pins of the potentiometer is measured by the ohmic blocking of the multimeter, and the measured resistance value is the nominal value of the potentiometer. If the pointer of the multimeter is fixed or the resistance value is more related, the measured potentiometer is damaged.

Second, the detection method of the contact between the movable arm of the potentiometer and the resistor piece.

The schematic diagram of using a pointer multimeter to detect the contact between the movable arm of the potentiometer and the resistor piece is shown in figure 2.

Fig. 2, a schematic diagram of the detection of the contact between the movable arm of the potentiometer and the piece of the electric device.

The ohmic gear of the multimeter measures the resistance between the 1 and 2, 2 and 3 pins of the potentiometer and rotates the shaft handle of the potentiometer counterclockwise to a close position.

(2) on the basis of the above detection, when the shaft handle is rotated slowly, the resistance value should gradually increase, the gauge needle should move smoothly, and when rotated to the extreme position of 3, the resistance value should be close to the nominal value of the potentiometer.

If the measured results are in accordance with the above law, the measured potentiometer is in good condition. If, in the above measurement, the pointer of the multimeter beats during the rotation of the rotating shaft of the potentiometer, it indicates that there is a bad contact between the variable contact and the resistor chip. When this potentiometer is used to control the volume of the radio, there will be noise; when the machine is vibrated, there will be a "clack" sound.

Third, the detection method of switch.

For the potentiometer with switch, the detection method of the switch is as follows.

According to the method shown in fig. 3, the resistance value between the 4 and 5 feet of the potentiometer is blocked by a universal meter, and the shaft handle of the potentiometer is rotated so that the switch is turned on and off, At the same time, observe whether the multimeter pointer is zero (open state) or infinity (off state). It should be turned on and off a few more times to determine whether it is normal.