Electronic kilowatthour meter

摘要

An electronic meter is disclosed, for measuring functions such as power and energy of an alternating current and voltage. For measuring electrical energy, the meter includes an analog integrator for computing the integral of the voltage and of the current over a selected period of the voltage waveform. Means including a digital microprocessor and a comparison circuit are provided for generating a voltage level equal to the magnitude of the current integral or the voltage integral. In this manner, the microprocessor determines the value of the voltage or current integral. Since the integral of a sinusoidal waveform is related to its amplitude and to the power factor, the microprocessor can make a computation of energy from the values of the voltage and current integrals.