In the daily electrical work, the multimeter is used in electrician maintenance work and is an indispensable measuring tool. Many novice electricians will burn out the multimeter accidentally in the process of using the multimeter. Let’s have a simple exchange and learn what matters need to be paid attention to when using the multimeter.
1. The selection of the measurement range is wrong, that is, when the current or voltage of the circuit under test is not known, it is necessary to start with a large range and then gradually reduce the range.
2. Wrong selection of voltage and current gears, using the voltage gear of the multimeter to measure the current, or using the current gear to measure the voltage, etc. will burn the multimeter, as well as the DC voltage gear on the multimeter, AC voltage gear, AC current gear and DC current gear must be clearly distinguished before measurement during use, and the gears must be clearly seen.
3. When measuring voltage and current, the range cannot be changed during the measurement. For a simple example, if you are measuring voltage and find that the range selection is too large, you cannot directly change the range while measuring. And most importantly.
4. The position of the red and black test lead jacks must not be inserted in the wrong place. Some multimeters have many jacks on them. There is a com terminal on the top of which is a black test lead. When measuring voltage and resistance, the red test lead is inserted on the right side. There are sockets for voltage: V and resistance ohm marks, and on the left side of the meter are two sockets for measuring current, one for high current at 20 amps, and one for low current at 200 mA. When measuring the current, a multimeter must be connected in series in the circuit to measure it. When measuring capacitance, the red test lead is inserted into this jack, be sure to pay attention, otherwise it is easy to burn out the multimeter.
5. When measuring the capacitance, the function of the capacitor is to charge. It needs to be discharged during the measurement process. We can directly short-circuit the small-capacity capacitor for discharge. The two wires are short-circuited together, and the large-capacity capacitor needs to be connected in series. Be sure to remember to discharge light bulbs or electrical appliances, otherwise there will be a danger of electric shock.
6. The resistance gear and the buzzer gear are a jack, and the hfe gear is the gear for measuring the triode. When measuring, you must remember to power off the measurement, and do not measure with electricity, otherwise the multimeter will burn out.
7. The DC voltage range is divided into positive and negative poles, especially for pointer multimeters, if the positive and negative poles are reversed, it is very likely that the pointer will reverse and bend the needle. These are all things to pay attention to. It can be seen on the dial of the multimeter that the maximum DC voltage is 1000 volts, the AC voltage is 750 volts, the maximum AC and DC current is 20 amps, and the minimum is 20 mA. When measuring, the maximum range of the multimeter cannot be exceeded. From the selection of a large gear to a small suitable gear, special attention must be paid. These are the most basic and basic knowledge for the use of multimeters.
