Electronic Doorbell Light Circuit using NE555


This 6V battery operated doorbell light circuit can be connected in
parallel with any existing AC230V doorbell. When anyone push the
doorbell switch, the bell sounds as usual and ac mains supply available
across the doorbell is routed to the input of this circuit through an
opto-coupler(IC1).
 

Conduction of IC1 triggers a monostable, wired around the good old 555
timer (IC2). As a result the high-bright white LED (D2) at the output of
IC2 is switched on for a short time. This circuit is highly useful at
night/midnight as it gives sufficient indoor light to help you locate
switches for room lamp/porch light, etc. On/Off duration of the LED
light can be increased/decreased by increasing/decreasing the value of
C2.

The electronic doorbell light circuit is fully safe because it is
perfectly isolated from the fatal ac mains supply by IC1. However, keep
to avoid accidental contacts with the front end of the circuit, which is
directly connected to the ac supply. Use of a good and convenient ABS
enclosure is recommended for this doorbell light unit.

Electronic Doorbell Light Circuit Schematic

 


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