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Basic Circuit Question? Answered

I am making a box that when opened will sound an alarm.  When it is closed, the contacts are touching, thus completing the circuit.  When the box is open they are not touching.  How can I make a circuit that will realize when theyre not touching(without using an Arduino or other programmer)???

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lemonie
lemonie

Best Answer 10 years ago


You can do this without a microprocessor, but why not make a switch that works the other way?

L

t.bmp
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seandogue
seandogue

Answer 10 years ago

To further Lemonies sound answer, most microswitches (those little switches you'll see if you crack open a mouse that engage with very low travel) are configured as SPDT or single pole, double throw switches, meaning that they can be used either as a normally closed or normally open switch, allowing you to choose the mode per application.

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Jack A Lopez
Jack A Lopez

Answer 10 years ago

Picture of two microswitches found inside an old computer mouse:

old-mouse-microswitches.jpg
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seandogue
seandogue

Answer 10 years ago

Thanks Jackalopes. Exactly what I meant.

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crocboy
crocboy

10 years ago

Thanks lemonie! I just kind of had a brain fart and never really thought about that.