Electrical Meter

Meters are instruments that measures a value in real time

An ammeter measures current in units of mA, it has an in side and an out side and measures the current from the in side to the out side

A voltmeter measures voltage in units of V, it measures voltage form its positive side to the negative side

Reverse Current

If a voltmeter is supplied with current that travels from the negative side to the positive side, the voltage is reversed

An Ohmeter measures resistance by measuring the voltage of a standard voltage source