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Light/Dark Detector

This handy little circuit can tell the difference between darkness and light, making it very useful for switching on and off signs, porch lights or other things when it gets dark or light.

Schematic


Schematic for Light/Dark Detector

Parts:


Part
Total Qty.
Description
Substitutions
R11100K Pot
Q112N3904 NPN Transistor2N2222
Q21NPN Phototransistor
RELAY19V Relay
MISC1Board, Wire, 9V Battery Snap (if battery used), Knob For R1

Notes:

1. R1 Adjusts sensitivity

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