Electricians encounter a variety of faults in their daily work. This is the time to determine where the point of failure, quickly determine the point of failure. There are many common methods used by electricians to determine the short circuit method, open circuit method, voltage method, current method, resistance method. how to test pcb board with a multimeter?The multimeter is the most common tool used by electricians.

Here is an introduction to the multimeter. Although it is called a multimeter, its functions are limited. Early multimeters could measure voltage, current, and resistance, and were also known as tristimeters. As the multimeter evolved, it was able to measure more and more quantities, such as capacitance, inductance, frequency, and duty cycle. Advanced multimeters can also be used as oscilloscopes.

First, how to use a multimeter to check for short circuits?

A short circuit, is a circuit or a part of a circuit that is short-circuited. After a short circuit, the current in the circuit will develop a sharp rise. If a switch is not tripped in time and the short circuit problem manages to exist for a long time, the circuit will heat up. It may smoke and burn the main parts of the equipment, or the business or even we may catch fire and cause a social fire (most building fires are caused by short circuits in electrical wiring).

Judgment method: digital multimeter switch file can be used to measure, need to determine whether the two measurement points are short-circuited, if the multimeter beeps and resistance is close to zero, basically can be judged as a short circuit; for mechanical multimeter, you can switch the instrument to the resistance of the X-1 file and make the two multimeter pens short-circuited and zero, if the measurement of the resistance value is close to zero,pcblink 1oz vs 2oz Copper basically can also be judged as a short circuit.

Why don't you say it must be a short? Due to the small internal resistance of some devices, it is difficult to determine whether there is a short circuit with the above method, such as AC and DC motors, induction coils, etc..

Second, how to use a multimeter to check for open circuits?

An open circuit, which is the opposite of a short circuit, is a circuit that is blocked and disconnected. It can also be judged by the resistance file of the multimeter.

Judgment analysis method: measurement work needs to be carried out to determine whether the enterprise can exist open circuit of the two main measurement points. Use the multimeter resistance gear from the low gear through the measurement. If the multimeter always research shows infinite value or resistance value is very large, then you can get the initial establishment of judgment for open circuit. This is also the same as the short circuit measurement results, can not be immediately determined as an open circuit. Because it also needs us to determine the characteristics of the object to be measured.

How to use a multimeter to check leakage?

The measurement value of the multimeter can be used as a basis for judgment. If you suspect that the equipment is leaking, you can use the high resistance gear of the multimeter to measure, and you need to determine the resistance value of this position to ground or to the shell. Usually, the resistance value is infinity or very large. If the resistance value is small, it must be a leakage.