How can I get one light to turn on while the other turns off automatically?


Old 06-26-11, 07:31 PM
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How can I get one light to turn on while the other turns off automatically?

This might be a complex question, but I don't know where else to ask.

I am working on a lighting system for my aquarium. I have a 17W fluorescent bulb and a blue 12V LED strip to act as a moonlight for the aquarium. The 12V LED light has already been wired up to a converter, so it will run off of house current.

My question is this- how can I wire things up, to have my LED strip to come ON automatically when I turn the 17W fluorescent bulb OFF? and vice versa.
Is this even possible? I plan on having this setup on a timer switch as well.

Thanks in advance.
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Old 06-26-11, 07:59 PM
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Use a relay with one set of normally open contacts and one set of normally closed contacts. Use a relay with a 120v coil and control it through your timer.
Old 06-27-11, 07:09 AM
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Another solution would be to use a three way switch. Power in on the common terminal. The two switch controlled hots on the travellers. With this setup one light source will always be on. You could install a single pole switch ahead of the 3w if the lighting needs to be off.

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