An electricity meter is an instrument used to measure electrical energy, also known as an electricity meter, a fire meter, or a kilowatt hour meter. It refers to an instrument used to measure various electrical quantities. The model of an electric energy meter is represented by an arrangement of letters and numbers, including category code, group code, design number, and derivative number. When using an energy meter, it should be noted that under low voltage (not exceeding 500 volts) and low current (tens of amperes), the meter can be directly connected to the circuit for measurement. In the case of high voltage or high current, the energy meter cannot be directly connected to the line and needs to be used in conjunction with voltage transformers or current transformers. When the electricity meter is connected to the circuit under test, alternating current flows through the current coil and voltage coil, and these two alternating currents generate alternating magnetic flux in their iron cores; The alternating magnetic flux passes through the aluminum plate and induces eddy currents in the aluminum plate; Eddy current is subjected to force in the magnetic field, causing the aluminum plate to receive torque (active torque) and rotate. The greater the power consumed by the load, the greater the current passing through the current coil, and the greater the eddy currents induced in the aluminum plate, resulting in a greater torque for the aluminum plate to rotate. The magnitude of the torque is directly proportional to the power consumed by the load. The higher the power, the greater the torque, and the faster the aluminum disc rotates. When the aluminum disc rotates, it is also subjected to the braking torque generated by the permanent magnet, which is opposite to the direction of the active torque; The magnitude of the braking torque is proportional to the rotational speed of the aluminum disc, and the faster the aluminum disc rotates, the greater the braking torque. When the active torque and braking torque reach a temporary balance, the aluminum disc will rotate at a uniform speed. The electrical energy consumed by the load is proportional to the number of revolutions of the aluminum plate. When the aluminum disk rotates, it drives a counter to indicate the amount of electrical energy consumed. This is the simple process of working an energy meter