Use of Multimeter in Home Appliance Repair
① Digital multimeter: Before measuring, first switch to the measuring gear. It should be noted that the gear marked is the range, which is the maximum value
② Mechanical multimeter: The method of measuring current and voltage is the same as the mathematical formula, but when measuring voltage, the reading needs to be multiplied by the value on the gear to obtain the measured value For example, the current gear is "X100" and the reading is 200. The measurement question is 200X100=20000 Ω=20K. The "Ω" ruler on the dial is from left to right, from large to small, while others are from left to right, from small to large
Precautions for multimeter
① To adjust the "zero point" (only available on mechanical watches), before using the watch, check that the pointer is pointing to the "zero position" on the left end. If not, slowly turn the "starting point zero position" correction screw in the center of the watch case with a small screwdriver to make the pointer point to the zero position
② When using a multimeter, it should be placed horizontally (only mechanical devices have it)
③ Before testing, it is necessary to determine the measurement content and turn the range conversion knob to the corresponding measurement gear shown to avoid burning the meter head. If the size of the measured physical quantity is unknown, the test should be started from the large range first
④ The probe should be inserted correctly into the corresponding socket
⑤ During the testing process, do not rotate the gear shift knob arbitrarily
⑥ After use, be sure to adjust the gear shift knob of the unused meter to the maximum range gear of the AC voltage
⑦ When measuring DC voltage and current, attention should be paid to the positive and negative poles of the voltage, the direction of the current, and the correct connection with the probe
