How does a domestic electricity meter work?
An electricity meter is designed to measure the total electrical energy consumed in a house, usually in kilowatt-hour (kWh). It computes the integral over time of the electrical power (in Watts) consumed on the power network delivered to the house. This electrical power is measured by performing the product of the line current (in Amps) and the line voltage (in Volts). Electricity meters typically consist of two parts: – a transducer to convert the power into a mechanical or electrical signal, and – a counter to integrate and display the value of the total energy that has passed through the meter. The simplest way to measure the line current and voltage for single phase electronic meters is: – line current: amplifying the voltage drop induced by this current traveling through a low-value (below 1 Ohm) shunt resistor in series with the load (all the appliances used in the home). – line voltage: amplifying the voltage in the mid-point of a resistive divider located between the phase volt
