DPDT Switch???

Discussion in 'General Electronics Chat' started by Gauzz, Jun 7, 2011.

1. Gauzz Thread Starter New Member

Jan 5, 2011
12
0
Hello, I'm trying to alternate (open/close) a couple circuits for an electronics project with a single switch and I believe that a DPDT switch will do but I'd like your advice, since I'm such a noob and maybe other type of switch is more adecuate (DPST)?

I'm thinking about a DPDT switch with no "Off" position.

This is what I'm trying to do: http://img821.imageshack.us/img821/9083/dpdtswitch.png

The idea is that when Circuit1 is open Circuit2 is closed and the other way around.

Last edited: Jun 7, 2011
2. #12 Expert

Nov 30, 2010
16,705
7,355
I believe you have it correct with the imageshack picture.

Gauzz likes this.
3. whatsthatsmell Active Member

Oct 9, 2009
102
4
I hate to be contrary, but I see smoke looming on your horizon.

First, you usually don't need to switch both the positive and negative sides of the circuits, so you should be able to get by with a single pole double throw switch.

But if you decide to go with the DPDT, terminals B and E (per your diagram) can not be tied together as shown. These are the feed terminals for the outputs on the switch, and will create a direct short and a lot of smoke!

4. Ron H AAC Fanatic!

Apr 14, 2005
7,050
657
You are assuming the two circuits have a common node, and you may be correct, but to do strictly what he asked, his circuit will do what he wants.
For example, assume circuit 1 is a battery, a resistor, and an LED, all in series. Circuit 2 is the same thing. This switch arrangement will close one circuit or the other, while keeping them totally isolated from each other.

PS AFAIK, switches don't have "feed terminals".

Last edited: Jun 7, 2011
5. Gauzz Thread Starter New Member

Jan 5, 2011
12
0
Hey thanks for your answers, I think I should have put "Ground" instead of "-" but the circuits won't make any kind of smoke since I have it all wired and the tracks are closed already, what I need is a way to have one open while the other is closed and viceversa. I know I'm making the switch work kind of backwards since terminals B and E are tied together.

I'll give a try to the DPDT.

Thanks.

Last edited: Jun 8, 2011