How to use a multimeter to test continuity, two testing methods can help you
I believe many people are not very clear about how to detect short circuits in home circuits. Let's first talk about what a short circuit is. A short circuit is caused by the power supply directly forming a loop without load, such as phase to phase or phase to zero in a three-phase 380 circuit. Direct connection, direct connection of 220 single-phase live wire and neutral wire will cause short circuit problems in the line.
Because it is directly connected, the resistance of the wire is very small. According to I=U/R voltage divided by resistance, it can be seen that the instantaneous current is very large, and the wire will be burned directly, which can easily cause a fire.
I have previously introduced how to use a multimeter to measure short circuits and open circuits in circuits. Friends who have read this article believe that you already know how to use a multimeter to troubleshoot basic short circuit faults. Measuring short circuit means measuring continuity. You can use either an analog multimeter or a digital multimeter. You can use either the buzzer mode or the resistance mode. There is not much difference in the measurement steps.
Note: When measuring without electricity, be sure to cut off the power in advance.
Some multimeters have the buzzer and diode settings together, while others have them separately. The graphic symbols of the buzzer mode of some multimeters are in the shape of ♬, and most of them are similar to WIFI signal graphics. Just remember these two graphic symbols.
Note that the power must be turned off during measurement. However, the power cannot be turned on even if there is a short circuit. The air switch will trip in the event of a short circuit.
1. Set the gear to the buzzing gear, and then touch the red and black test leads. If there is a buzzing sound, it means the gear is normal. Then, each of the red and black test leads touches the measured point, and a buzzing sound indicates that there is a short circuit.
2. Set the gear to the resistance low range, and touch the red and black test pens. If the resistance value is 0, it is normal, and then the red and black test pens each touch one end of the measured point. If a very small resistance value is displayed, it is also a short circuit.
