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I have a situation where I've got a few electronics boards stacked on top of each other. I don't want the boards to be powered when stacked but when they're no longer on top of one another I want them to turn on. I figure a push switch that is off while depressed but on when compressed makes sense to me, is there a specific name for this type of switch?

ThePlanMan
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  • Microswitch maybe? It needs a very low force pressure and can be soldered in NO (normally open) and NC (normally closed). Depends on your mechanical layout what switch you need. Maybe upload your PCB, if you don't have one yet than you can take a look at the microswitches. – Weaverworm Nov 27 '15 at 15:42
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    Normally-closed switch? Also called NC. Or a Single pole, double throw (SPDT) switch, which has both connections (NO and NC). See here on wikipedia – frarugi87 Nov 27 '15 at 15:42

3 Answers3

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enter image description here

Top one is "normally closed" and the bottom one is "normally open"

You want the top one it seems.

Andy aka
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  • Thanks for the quick answer. Can you share a link to a small normal closed switch to make sure I've understood correctly please? – ThePlanMan Nov 27 '15 at 15:57
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    Is that a good idea to have that switch to provide power to the board? I would rather have that switch to enable/disable the power components such as LDOs that provide the power to the board. – Nazar Nov 27 '15 at 16:25
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    @Naz It's a good point and the OP should be aware that the switch chosen should be adequate for the job it has to do. – Andy aka Nov 27 '15 at 17:07
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Another name i've seen for this is "push to break" (the counterpart to "push to make").

Peter Green
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Another useful name to know (digikey filter): On-Mom. Means that this switch is normally closed and when pressed stays momentary off.

Gabriel Rezende Germanovix
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