1. Nustatykite ar ar the circuit ar device is live or not

The AC voltage range of a digital multimeter is very sensitive, even if there is a small indukd voltage around it, it can display it.

Based on this feature, it can be used as a testing pen.

The usage is as follows: Set the multimeter to the AC20V position, with the black lead hanging in the air, and hold the red lead in contact with the line or device on the side. At this time, the multimeter will display a number. If the number displayed is between a few volts to more than ten volts (different multimeter displays different values), it indicates that the line or device is live. If the display is zero or very small, it indicate that the line or device is not live.

2. Išskyrimas ar arba galia maitinimas linija is a tiesioginė linija arba a neutrali linija

The first method: You can use the above method to determine: the one with a larger number is the live line, and the one with a smaller number is the zero line. This method requires contact with the measured circuit or device.

The second method: does not require contact with the measured circuit or device. Set the multimeter to AC2V position, with the black lead hanging in the air, and hold the red lead in hand to gently slide the tip of the pen along the line. At this time, if the meter shows a few volts, it indicates that the line is live.

If the display show only a few tenths of a volt or even less, it indicate that the line is a zero line. This method of judgment is not directly in contact with the circuit. It is not only safe but also convenient and fast.

3. Find the break point of the cable

Kai yra yra lūžio taškai in the cable, the traditional method is to use a multimeter resistance block to search for the breakpoints in the cable section by section. This not only wastes time, but also greatly damages the insulation of the cable. By utilizing the sensing characteristics of a digital multimeter, the disconnection point of the cable can be greitai identifikuota.

First, use a resistance gauge to determine which cable core wire has broken circuit. Then connect one end of the broken core wire to the AC220V power supply. Then, set the multimeter to the AC2V position, with the black probe hanging in the air, and hold the red probe to gentley slide of the pen along the line. If there is a voltage of a few volts or a few tenths of a volt (priklausomai on the cable) displayed on the meter, and if it moves to a certain position, the display on the meter staiga mažėja a lot, Write down this position: generally. The breakpoint is located between 10-20cm in front of this position.

4. Measure the frequency of UPS power supply

You can connect a 220V/6V or 220V/4V step-down transformer to the output terminal of the UPS power supply, reduce the voltage without changing the frequency of the power supply, and then connect the frequency shift to the output of the transformer to measure the frequency of the UPS power supply.