switch wiring question

Shock_Hazard · Joined: Jul 17, 2015 Posts: 16 Location: Gwynedd

Here's a puzzling problem which I'm trying to figure out, is there any way to make a 3 position dpdt switch with a "centre off" function connect 3 different combinations:
A to B
A to C
A to B & C?

note: the switch is not a dp3t switch which swaps over one side of the contacts in the centre position, it's a 3 position dpdt switch where the centre is "off" wherein no contacts connected to the common contact.

I don't think it's possible but maybe you can rise to this challenge and prove me wrong Smile

blue hell · Posted: Fri Jul 17, 2015 6:14 am Post subject:

I guess it would depend on the side effects the actual circuit would provide ... and in general .. indeed not possible I think.

And welcome

Shock_Hazard · Joined: Jul 17, 2015 Posts: 16 Location: Gwynedd

Hello Blue Hell... Your username gives me horrific visions of the blue man group torturing sinners. Razz

Thanks anyways, I suspected there is no way... to clarify what I'm doing, it's all analogue, I'll be switching (for exmaple) two signals via resistors (C and B) to an audio input (A).
So if impossible I'll call for...
ANY ALTERNATIVES?

Shock_Hazard · Joined: Jul 17, 2015 Posts: 16 Location: Gwynedd

just fyi I found a way to do this with a switch with the operation specified below (not sure what the technical name for this kind of operation is) however I'm not going to spoil the fun just yet, try and figure out how it's done Wink

switch operation.png

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PHOBoS · Posted: Sat Jul 18, 2015 5:33 am Post subject:

Déjà vu, check out this thread. Cool

Shock_Hazard · Joined: Jul 17, 2015 Posts: 16 Location: Gwynedd

Very useful, thankyou, some good insights in that thread but I don't think that solution fits my problem exactly; I'm not necessarily switching between 3 signals but choosing between either of two signals or both, so one switch position has to "short" them together. Also I could do it with logic easily, a multiplexer would work fine as I need to keep things analogue here (sinking and sourcing in my circuit), but unfortunately that would cost too much. If I could afford additional components I wouldn't even ask this question Laughing

With excess money comes the luxury of excessive circuitry.

PHOBoS · Posted: Sun Jul 19, 2015 3:32 am Post subject:

Shock_Hazard · Joined: Jul 17, 2015 Posts: 16 Location: Gwynedd

assuming that in position 2 both the centre contacts are connected and in position 3, only the right contacts are connected, then yes, that is one way Smile

I acctually had a different way but both work perfectly Very Happy