Does "red in and black out" apply to all digital multimeters?
Red in and black out are for voltage measurement and current measurement. During voltage measurement and current measurement, the multimeter is not connected to the power supply. The reason why red in and black out is for the deflection of the pointer of the analog multimeter ammeter. In the digital multimeter, if the red test lead is not connected to a high potential, the current or voltage measured at this time is a negative number. When performing diode measurement, the multimeter is connected to the power supply, and the red and black test pens will be connected to the positive or negative pole of the internal power supply at this time.
