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Light activated switch 2011-09-04

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3lectrix

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3lectrix submitted a new article:

Light Activated Switch - The circuit is based on National Semiconductors comparator LM311 (IC1) and an LDR. The non invertin


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Hysteresis can be added by connecting a 100kΩ resistor from the pin 7 to pin 2. 100k may not be the optimum value, depending on the light source. It might also be helpful to connect a 10-100uF cap across the LDR, to filter out hum from artificial lights.
 
I can not understand why I see so many circuits powered by 9V batteries which have low capacity & hold little charge.
Surely 4 x AA's or 6V lantern battery offer lower cost & convenience.
I am a bit disappointed the poster acknowledged relay chattering as a probable event but offered no solution, leaving it to Roff (thanks for the input) to suggest remedies.
Surely the poster might acknowledge & update his circuit?
 
Can you help me construct a circuit that can turn on a light when it is dark,and can turn it off when there is light in the surrronding.i am using a pic P16f84A.may God bless you!
 
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