How can you tell if a multimeter is normal?
Multimeters are divided into digital and analog. The following are the methods for judging whether it is normal or not.
For the pointer multimeter, you can shake it gently in your hand. If the pointer is abnormally flexible and keeps moving, you can judge that the meter is broken. Because the shunt resistance of the meter head can make the hands of the meter damp and stop quickly. Otherwise, the resistance is open circuit or the moving coil is broken.
For the DC voltage range, you can find a battery or DC power supply, and set the watch to a position slightly higher than it (for example, use a 5V range to measure a 1.5 or 3V battery) for measurement. The AC voltage file can be used to measure the 220V mains directly with 250 or 500v files.
The resistance file needs to be tested with a battery. When the test pen is short-circuited, the pointer should swing at full range, and then use the zero-adjust potentiometer to adjust the pointer to the full-scale 0Ω position. Every time you change a gear, you need to adjust the 0 position slightly. The 10K gear needs to be equipped with a 9Ⅴ or 15ⅴ high-voltage battery to work. The Rx10K range of most 9V multimeters uses two batteries of 9v and 1.5v in series, so the two batteries are indispensable when using this gear. And 15v is generally high and low voltage separate power supply does not affect each other.
For digital meters, the first thing to do is to install the batteries and turn on the power switch. The screen should now be displayed. Turn the knob to the resistance level and then short-circuit the test leads, all resistance levels should display 0Ω, only the 200Ω level may have a resistance of a few tenths of ohms, which is a normal phenomenon. When the short-circuit test pen is turned to the buzzer position, a sound should be heard. Then switch to the voltage file, and the specific test method is the same as that of the pointer meter.
