Precautions before using the digital multimeter True rms :
If the multimeter cannot determine the signal amplitude when measuring a certain parameter, try to select the automatic gear and let the meter switch by itself.
When using the resistance and current gears, pay attention to the selection of the measurement function on the multimeter and the connection method of the test leads, otherwise the multimeter will be damaged.
E.g:
1. When selecting the resistance gear, measure the voltage directly, and the multimeter will burn out.
2. When the test lead is connected to the current test port to measure the voltage of the circuit, because the internal resistance of the current connection port is very small, the circuit will be short-circuited, and the short-circuited circuit will instantly generate a large current flowing through the multimeter, and the multimeter will be burned. .
3. If the test lead is connected to the voltage test port to measure the current, the internal resistance of the voltmeter is extremely large, and the multimeter will be connected in series to the circuit when measuring the current.
Therefore, the multimeter will divide most of the voltage of the circuit due to the extremely high internal resistance, so that the power of the entire circuit power supply is added to the internal resistance of the multimeter, causing the multimeter to burn out.
