Measure and record over time the electric power flowing through a circuit. A precise fraction of the current flowing in the circuit is diverted to operate the motor. The speed at which the motor turns is proportional to the current in the circuit, and, therefore, each revolution of the motor’s rotor corresponds to a given amount of current flowing through the circuit. The counter is connected to the rotor and adds and displays the amount of power the circuit has carried based on the number of revolutions of the rotor. The counter is usually marked in kilowatt-hours (1,000 watt-hours). Measures 2″ wide x 1″ tall.