Electronic Circuits and Tutorials
Electronics Schematics - G

Ground Fault Interrupter (GFI) Circuits

Broken Bulb safety trip:  12/14/98 Electronic Design - Ideas for Design / A classic safety requirement involves disconnecting the ac mains supply from a light bulb should the glass envelope become broken. Although the filament can draw a much higher than normal current upon exposure to air prior to burning out.

G.F.C.I.:  A Ground Fault Circuit Interrupter (GFCI) is a device to protect against electric shock should someone come in contact with a live (Hot) wire and a path to ground which would result in a current through his/her body. The GFCI operates by sensing the difference between the currents in the Hot and Neutral conductors. Under normal conditions, these should be equal. However, if someone touches the Hot and a Ground such as a plumbing fixture or they are standing in water, these currents will not be equal as the path is to Ground - a ground fault - and not to the Neutral. This might occur if a short circuit developed inside an ungrounded appliance or if someone was working on a live circuit and accidentally touched a live wire.

Ground Fault Interrupter

Ground Fault Interrupter:  National Semiconductor Application Note MP1851 June 1992

Ground Fault Interrupter: 

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