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I need a DT, ON-OFF-ON switch to control two independent circuits with no common connection. I need something that behaves like either A and B, or C and D in the diagram below. Does such a thing exist? This seems pretty straightforward, but I haven't been able to find one.

In the diagram, A closes one circuit and B closes the other; the other possible configuration would be one in which C closes one and D closes the other.

Diagram showing required switch configuration

update:

Thanks for the suggestions. Here's how the switch I bought works and how the pins are configured. I just need to put a jumper across 2 and 5, which are common, and connect one circuit to 1 and 4 and the other circuit to 3 and 6.

DPDT switch diagram

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  • \$\begingroup\$ If you want to control 2 independent circuits, then you may want to look into Double Pole switches. Double Pole is not the same thing as Double Throw, even though it's sometimes implemented in a single DPDT switch. \$\endgroup\$ – Nick Alexeev Apr 27 '16 at 19:38
  • \$\begingroup\$ A DPDT switch would satisfy your A-B situation as long as you can accept 1-3 & 2-4 in A and 4-6 & 3-5 in B. \$\endgroup\$ – brhans Apr 27 '16 at 19:49
  • \$\begingroup\$ I think if I had drawn a normal DPDT switch, 3 and 4 would be common, the "up" position would connect 1 to 3 and 2 to 4, and the down position would connect 3 to 5 and 4 to 6. So, if I permanently connect 3 to 4, I could connect one circuit to connectors 1 and 2, and the other circuit to connectors 5 and 6. Does this seem right? \$\endgroup\$ – dcorsello Apr 27 '16 at 20:04
  • \$\begingroup\$ 3 and 4 are not common in a normal DPDT switch. A normal DPDT has 2 completely electrically independent switches with a common physical control level/knob/slider/whatever. \$\endgroup\$ – brhans Apr 27 '16 at 20:24
  • \$\begingroup\$ Terminals 1, 3, and 5 are one pole of the switch, and 2, 4, and 6 are the other. Connect one circuit to terminals 1 and 3, and the other circuit to terminals 4 and 6. \$\endgroup\$ – Peter Bennett Apr 27 '16 at 20:27
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schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ Right. So in this diagram I would permanently connect 1 and 6. Circuit A (nothing to do with my diagram) would connect to 3 and 4, and circuit B would connect to 2 and 5. Correct? \$\endgroup\$ – dcorsello Apr 27 '16 at 20:13
  • \$\begingroup\$ @DwaneReid: The terminal numbers in your drawing do not match the terminal numbers in the OP's drawings (at least, not for DPDT switches I've used). \$\endgroup\$ – Peter Bennett Apr 27 '16 at 20:29
  • \$\begingroup\$ @dcorsello: You would connect one circuit to terminals 1 and 3, and the other to 6 and 5 (using Dwayne's numbering) \$\endgroup\$ – Peter Bennett Apr 27 '16 at 20:31
  • \$\begingroup\$ @PeterBennett: The terminals in the original question do NOT refer to an actual physical switch. What is clear is that one pole of the switch moves the armature (pin 1) between pins 2&3. The other armature (pin 6) moves between pins 4&5. \$\endgroup\$ – Dwayne Reid Apr 27 '16 at 22:13
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An ON-OFF-ON switch is a three position switch, with the middle position disconnecting everything. If that's what you want, then you'll need a Double-Pole-Double-Throw switch with a center-off position. There's an excellent selection at DigiKey

A Double-Pole switch comprises two independent switches in the same housing, and most DPDT switches have the commons as the center terminals and the made contacts on the opposite side of the switch with reference to the tip of the toggle.

When you go to wire it, if it's a conventional switch, the wiring should go like this:

enter image description here

In any case, you should test continuity with the toggle in its various positions in order to decide which circuit goes where.

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You just described a common DPDT switch, just with center-off.

It's even simpler. Here I've drawn in how to do it on your switch's diagram.

I also scrawled in an old fashioned knife switch with brass blades and a purple handle (for Prince) so you can visualize what's going on. Purple is an insulator.

enter image description here

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  • \$\begingroup\$ The only reason to do as you describe in your edit (connect "one circuit" to 3 and 6, and bridge 2-5) is if you need a double air-gap to snuff the arc of a particularly high voltage or high inductance. \$\endgroup\$ – Harper - Reinstate Monica Apr 28 '16 at 7:07

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