Patent ID: 6031750
Filing Date: 2000-02-29
Classification: G05F,H02M

Abstract:
A multi-voltage power supply to supply constant current from a phase terminal to a neutral or ground terminal, comprising:a) a bridge circuit having four connection points for coupling said bridge circuit to different input and output signals;b) a first one of said connection points connected to a phase conductor of an AC power source;c) an amplifier coupled to a second one of said connection points of said bridge circuit to receive therefrom a DC signal, said amplifier is made up of a first transistor and a second transistor connected as a Darlington amplifier;d) said first transistor of said amplifier has a base coupled to said second connection point of said bridge circuit, a collector coupled to said second connection point of said bridge circuit and an emitter, said second transistor has a base coupled to said emitter of said first transistor, a collector coupled to said second connection point of said bridge circuit and an emitter coupled to one end of a resistor;e) a first zener diode coupled between a second end of said resistor and a circuit ground;f) a capacitor coupled in parallel with said first zener diode;g) a third one of said connection points of said bridge circuit coupled to a first terminal connected to a neutral conductor or a building ground;h) a second zener diode connected at a first end to said capacitor and at a second end to said base of said first transistor;i) said amplifier having an output terminal whereby a constant current is available between said output terminal of said amplifier and said first terminal regardless of whether said first terminal is connected to a neutral conductor or building ground.