Patent ID: 7414818

Claim:
A receptacle type ground fault circuit interrupter device, comprising: hot and neutral input lines; hot and neutral output lines; an input circuit connected to the hot and neutral input lines and having an anode and a cathode; a leakage current detecting and amplifying circuit connected to the hot and neutral input lines; a neutral ground fault detecting and amplifying circuit connected to the hot and neutral input lines; a signal control circuit including an IC and a reset and trip actuating circuit, the IC being coupled to the leakage current detecting and amplifying circuit and the neutral ground fault detecting and amplifying circuit; an output circuit connected to the reset and trip actuating circuit; and a ground fault self detecting circuit connected between the input circuit and the reset and trip actuating circuit, wherein the ground fault self detecting circuit includes: an end-of-life indicator; an NPN transistor having a base connected to the anode of the input circuit and the reset and trip actuating circuit and an emitter connected to the reset and trip actuating circuit and to the end-of life indicator; a first light emitting diode for connecting to a power supply; a branch circuit including a capacitor and a resistor forming a parallel circuit and a photosensitive resistor coupled in series with the parallel circuit, the photosensitive resistor being optically coupled to the first light emitting diode, one end of the branch circuit being connected between the anode of the input circuit and the reset and trip actuating circuit and another end of the branch circuit being connected to the cathode of the input circuit; a test button; a reset button; a normally closed switch controlled by both the test button and the reset button, the normally closed switch being connected in series with the end-of-life indicator and connected in series with the first light emitting diode; and a one-way silicon controlled rectifier having an anode connected to the base of the NPN transistor and a control end connected to a connection point between the photosensitive resistor and the parallel circuit of the branch circuit.