How to use a multimeter to eliminate short circuit problems, and how to measure short circuits with a multimeter
The short circuit is caused by the power supply directly adding circuit without load. How to use a multimeter to measure the short circuit, how to use the multimeter to troubleshoot the problem of the short circuit, to measure the short circuit is to measure the continuity, the pointer multimeter or the digital multimeter can be used, and the buzzer can be used. or resistance gear to measure.
How to measure short circuit with multimeter
To measure whether there is a short circuit in the circuit, it must be measured without electricity.
If the power supply is connected to the circuit without the load to form a loop, it will cause a short circuit problem. For example, the direct connection between phase and phase or phase and zero in a three-phase 380 circuit, and the direct connection between the 220 single-phase live wire and the neutral wire will cause a short circuit.
In the case of direct connection, the resistance of the wire is very small. According to the current formula I=U/R, it can be seen that the instantaneous current is extremely large when the voltage is divided by the resistance. In the case of a short circuit, the wire will be directly burned out, causing a fire.
How to use a multimeter to eliminate short circuit problems, and how to measure short circuits with a multimeter
Different multimeters have slightly different gear designs. Some multimeters have the buzzer gear together with the diode gear, while others are separate. Some multimeters have beep gears with graphic symbols, most of which are similar to WIFI signals. graphics.
Although it cannot be powered on in the case of a short circuit, when there is a short circuit during measurement, it must be powered off for measurement to ensure the safety of the person and the multimeter.
1. Turn the gear to the beeping gear, touch the red and black test pens, and a beeping sound means the gear is normal. Then, the red and black test pens touch one end of the measured point, and a buzzer sounds to indicate that there is a short circuit.
How to use a multimeter to eliminate short circuit problems, and how to measure short circuits with a multimeter
The short-circuit test number shows 0 as normal. For a multimeter with a little error, it may display 1 or 2, which can generally be ignored, and there will still be a beeping sound.
2. Turn the gear to the low range of the resistance gear, touch the red and black test pens, and the resistance value is 0. The gear is normal. Then, the red and black test pens contact one end of the measured point, and if the resistance is very small, it means that there is a short circuit.
How to use a multimeter to eliminate short circuit problems, and how to measure short circuits with a multimeter
Note: During power failure measurement, selecting the wrong gear and range will not burn the multimeter. Only the current gear, voltage gear, capacitance gear, frequency gear and other live measurement gears will burn out the multimeter when the operation is wrong.
The above is the method of using a multimeter to eliminate short circuits, and the precautions for measuring short circuits with a multimeter. I hope it will be helpful to everyone.
