In modern days, the types of electric meter continuously operate to measure the instantaneous voltage and current and calculating the product of these to give out the instantaneous electrical power. The electric power is then integrated against time to give energy used. There are basically two kinds of electric meter categories, the electromechanical and solid state meters.
Electromechanical Technology: The most common electric meter type is the Thomson electric meter which falls under the electromechanical category. This was invented by Elihu Thomson in 1888. The working pf this electromechanical induction electric meter is very simple to understand.