How to use a multimeter to find short circuits?
Short-circuit measurement is very common in electrical maintenance and component fault location. When measuring short-circuit faults, be sure to disconnect the power supply, and remember not to operate with power on. For short-circuit measurement, use the buzzer or ohm profile of the multimeter to measure. The buzzer is used to measure more intuitively. When the line is short-circuited, the multimeter will "buzz" directly. The principle of buzzer is when the measured resistance is less than about 75Ω, the multimeter A beep occurs. If you want to know the resistance value between the two lines more accurately, you can use the 200Ω measurement. Using the buzzer mode to measure, sometimes the actual internal resistance between the two signals is small, it is easy to misjudge, such as relay/contactor coil, many relays/contactor coil impedance is less than 75Ω, using the buzzer mode measurement will The buzzer sounds like a short circuit, but it doesn't.
Engineers often use the buzzer of the multimeter to quickly find the short-circuit fault point of the line or components, such as measuring whether the resistance and capacitor are short-circuited, whether the diode is reversely broken down, whether the triode is broken down (when the triode is broken down, the base and emitter are generally short-circuited), Whether there is a short circuit between the power supply and the ground of the integrated circuit chip, whether there is a short circuit between two pins, etc.
