2¡¢ The on-off of the switch shall be accurate and clear, the operation cycle switch shall operate smoothly without jamming, and the circuit change shall be normal. Is the contact between the movable arm of the adjustable resistance touch switch and the resistor excellent. Measure both ends of "1" and "2" (or "2" and "3") with the ohm gear of the multimeter, and turn the rotating shaft of the adjustable resistance counterclockwise to the position close to "off". At this time, the smaller the resistance value, the better. Gradually rotate the shaft handle clockwise, the resistance value should gradually increase, and the pointer in the meter should move smoothly. When the shaft handle is rotated to the pole orientation "3", the resistance value shall be close to the nominal value of the adjustable resistance. If the pointer of the multimeter jumps during the rolling process of the shaft handle of the adjustable resistance, it indicates that the movable contact has the disadvantage of poor contact.
