So, I can get push-to-break switches that will break my circuit when pushed in. I assume this is how the light in my fridge works.
But how do these works? I would like to make something like this, but I have no room for a switch. My door closes very tight and I cannot drill any holes or mount any switches where it closes.
I can, however, run a wire on the door and on the flange it closes against, and have them touch to complete my circuit.
So I imagine, that using the push-to-break functionality, I can break when the wires touch, and un-break when they no longer touch.
I have no clue how to achieve this though. Maybe I am even thinking about this wrong.
How can I turn my lights on, when the door is open?
Best Answer
A simple way to do this, especially if you're switching 120V, would be to use a relay. Look for one that is either normally-closed ("NC") or has Form-C contacts. Form-C combines NO and NC contacts. Sometimes, in relays, Form-C is called "CO" or "SPDT":
You'll need some power source for the relay coil. Since this power is getting interrupted by your door contact, make sure it's not hazardous! Don't have a live 120V contact on the door jamb :)
Then, this is how you would hook it up:
(Sorry for my cheesy drawing!)
This idea could also be used with a solid-state relay, or even a MOSFET, if those would suit your applicaion better.
Good luck!