Short circuit is the most common fault in the circuit, is caused by the power supply no load direct circuit. For example, three-phase 380 circuits in the phase or phase zero direct connection, 220 single-phase fire wire and zero wire direct connection can cause a short circuit. Because of the direct connection, the resistance of the wires is very small. According to I = U/R voltage divided by resistance, the instantaneous current is so large that the wire will burn directly, which is very dangerous. Today, we will see how to troubleshoot with a multimeter. Measuring a short circuit is actually measuring the on-off. With a pointer multimeter or digital multimeter, buzzer or resistor can be, the measurement steps are similar.how to test pcb board with a multimeter？

Attention to safety matters: measurement without electricity

Introduction of each gear

Some multimeters buzzer and diode files together, some are independent. Individual multimeter buzzer graphic symbols are ♬ logo symbols, most of them are similar to the graphic of WIFI signal, we just need to remember these two graphic symbols. When the measurement must be disconnected, of course there is no short circuit on the power supply and the air switch trips on a short circuit.

1. Turn the gear to the buzzer and touch the red and black pens. If there is a buzzer, this gear is normal. Then touch the red and black probes to the end of the point being tested, if there is a buzz, it must be shorted.

Short circuit test

Short-circuit test digital display 0 is normal, the multimeter a little deviation, negligible, but still have a beep.

2. Turn the gear to the lower position of the resistance gear and touch the red and black probes. If the resistance value is 0, the gear is normal, then the red and black probes touch the end of the point being measured. If a small resistance value is displayed, pcblink 1oz vs 2oz Copperit is also a short circuit.

Resistance Gear

Very small reading

Remarks for clarification: because it is a power-off control measurement, so there is no wrong gear and range will not burn the multimeter, only through the current file and voltage file capacitance file frequency file and other charged time measurement of the gear and operational errors will burn the multimeter.