Momentary Confusion

[AudioEcstasy]

I've searched and couldn't find a thread so if there is one please redirect me.

I bought some of the Carling-style momentary switches from New Sensor. There are 3 pins, center and depending upon how you wire it the switch can be NO or NC. I wired it up for normally open (kill switch) but something weird happened. It works in reverse... When I test the switch with my MM it reads perfect continuity, when the switch is pressed it shunts to ground but it has the opposite effect in reality.

I have to push the switch down to get it to open. Obviously I can just switch the wiring, but why would it read continuity with the MM and work in reverse in reality?

Thanks!

[DiscoVlad]

I'd guess the logic the switch is connected to has the opposite active state to how your switch is connected.
Some logic switches "on" when the input is high, other logic switches on when the input is low (this is known as positive and negative logic, or the inputs are described as active high/active low)

[AudioEcstasy]

Thanks for the response! I'm still a little new to all of this...so basically the switch behaves differently when there is actual signal present vs. just testing it with the MM? I haven't had a chance to rewire them yet but I'm sure it'll be no problem.

Cheers!

[mth5044]

You said you wired it for normally open.. you'd want it normally closed for a kill switch, no? Normally open would mean when unpressed, the signal wouldn't be connected.

[artifus]

You said you wired it for normally open.. you'd want it normally closed for a kill switch, no? Normally open would mean when unpressed, the signal wouldn't be connected.

no - that can cause problems. you'd want it normally open so that when pressed the signal is routed to ground, killing it.