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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Tuesday, November 29, 2011 08:14 PM
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Lamp Controls
Switches |
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12v Light/Dark Switch |
Often, for certain low voltage lighting systems; you would like to turn off the
lights during the bright light of the day. Most commercial day/night
switches are designed for AC lighting. This hobby circuit below was designed
for a 12v DC system. But, it could be modified for other voltage as well.
It uses an inexpensive phototransistor as the light detector. An n-channel
FET is used to switch power to the lights. A transistor circuit is included
to provide some hysteresis. This keeps the circuit from fluttering the light
during the transition from day to night and night to day. It is recommended
that a plastic tube be placed over the transistor to prevent it from being
illuminated by the lights it is controlling. By selecting the appropriate
power FET, the circuit could control over 100 watts worth of 12v lighting.
(July 22, 2008) |
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Click on Drawing Below to view PDF version of Schematic |
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