Energy meter

An electric meter or energy meter is a machine that measures the amount of electrical energy supplied to a residence or business. These are customers of an electric company.

The most common type is more accurately known as a (kilo) watt-hour meter or a joule meter. They may also record other variables including the time, when the electricity was used. Modern electricity meters operate by continuously measuring the instantaneous voltage and current (amperes) and finding the product of these to give direct electrical power (watts) which is then integrated against time to give energy used (joules, kilowatt-hours etc). The meters fall into two essential categories, electromechanical and electronic. The type of meter described commonly used on a single-phase AC supply. Different phase of meter configurations use additional voltage and current coils. The most general type of electricity meter is the electromechanical induction meter.