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
R1 1 100K Pot  
Q1 1 2N3904 NPN Transistor 2N2222
Q2 1 NPN Phototransistor  
RELAY 1 9V Relay  
MISC 1 Board, Wire, 9V Battery Snap (if battery used), Knob For R1  

Notes:

1. R1 Adjusts sensitivity

Title: Light/Dark Detector
electronic circuit
Source: www.aaroncake.net/circuits/
Published on: 2005-02-10
Reads: 1390
Print version: Print version

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