Capacitor discharge electronic single-phase electricity meter - has stabilised direct voltage supply providing reference voltage for calibration

摘要

An electronic single-phase electricity meter operating on the capacitor discharge principle has a time division multiplexer multiplying the load voltage and a signal proportional to the current. The integrated current signal is compared with two limit values and a pulsed signal derived whose pulse frequency is proportional to power. Its circuitry is simplified compared to conventional arrangements so as to make it more economical and compact. Its direct voltage supply source has a precision voltage regulator in one or both branches. The stabilised direct voltage output acts as a reference voltage for all the calibration defining circuit elements. An operational amplifier comparator circuit is used. This drives an EXCLUSIVE-OR gate via a diode. The other gate input is connected to the reference potential and its output to the comparator positive input.