Variable resistor R1 adjusts the light threshold at which the circuit triggers. R1’s value is chosen to match the photocells resistance at darkness. The circuit uses a CMOS 4001 IC. Gate U1a acts as the trigger, U1b and c form a latch. S1 resets the circuit. The output device may be a low power piezo buzzer.
Kindly submitted by Mick Devine from the UK
Source :: http://www.zen22142.zen.co.uk/Circuits/Switching/ldet.htm
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This entry was posted on Tuesday, May 29th, 2007 at 2:16 pm and is filed under Circuit diagram, Digital, Lighting.
