Simple question: what type of switch is this

On Sun, 19 Mar 2006 17:46:21 -0500 in sci.electronics.basics, Michael Levin wrote,

That would be a three pole double throw switch; except that it's OK for both ground wires to be connected all the time so you really only need a double pole double throw, DPDT which are very much easier to find.

ok, cool; which wire, on one of those standard stereo plugs, is the ground wire? The thing has 3 sections. Which of the sections is the one that's ok to leave connected?

Thanks,

Mike

--

Mike Levin
mlevin77@comcast.net

And just for my edification, the 3PDT should have 12 contacts, right?

Mike

--

Mike Levin
mlevin77@comcast.net

Hi, Mike. Please take the time to read two short Wikipedia articles:

This will give you the technical terminology you need to understand your wiring problem.

You should go to Radio Shack and get a small DPDT switch, two stereo jacks and a stereo plug. Then you can wire it up like this (view in fixed font or M$ Notepad):

| Jack 1 | .----. | | | | | To---------. | | | | SW1A | | | '---o Plug 1 | | Ro------. __--o--. .----. | | | | .---o | | | | | | | | | '---oT | | | So---. | | | | | | | | | | | | | | '----' | | | .---oR | | | | | | | | | | Jack 2 | | | | | | | .----. | | | | | .-oS | | | | | '--)---o | | | | | | To---)-----' __--o--' | '----' | | | | .------o | | | | | | SW1B | | | Ro---)--' | | | | | | | | | | | | | So---o------------------' | | | | '----' | (created by AACircuit v1.28.6 beta 04/19/05

In the wiring diagram above, T stands for Tip, R for Ring, and S for sleeve. You can see in the wiring diagram that the two sleeves can be connected together.

If you keep the wiring short on your selector switch (a few inches), you can use 22AWG stranded hookup wire without problem. If you're an audiophile, you should look for a DPDT shielded switch with gold contacts which can do dry circuit switching (very low voltage at low/no current), and use shielded signal wire for the hookup. But for us mere mortals, the above should be OK for occasional use, as long as you use a new switch.

Good luck Chris

No - only 9. Each pole of a double-throw switch has three contacts - the common (moving) contact, and two fixed contacts, one for each position of the switch.

In your drawing above, your middle moving part should be connected directly to the car stereo input - you don't need the Y splitter there.

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3PDT

three pole (switches three circuits) dual throw (two "on" positions)

but.

you only need to switch the left and right signals the common can be left connected to both devices

1 2 IPod-L --------o--__ ~~o--------------------- L Sat-L ---------o 3 IPod-c ---. >-------------------------------- C Sat-c ----' 4 5 IPod-R --------o--__ ~~o--------------------- R Sat-R ---------o 6

STERIO PLUG (not to scale) ################>

# # common _ ______ ______________# #____________________ /~--__ / ## ## # # | | / ~~ ## ## # # | left | | / ## ## # # | |~~~~\\ \\ | \\ ## ## # # | | o ) |\\ | \\ __ ## ## # # | |____/ |/\\| \\_--~~ \\_##______##______________# # | right / \\ # # ~~~~~~~~~~ # # LEFT RIGHT COMMON ###############>

______ / /| /____ / | |1 2 3| | | | / |4 5 6|/ ~~~~~ back of DPDT switch

--

Bye.
   Jasen

that depends on the construction, for typical toggle and rocker switches that'd be right. but only 9 external terminals 3p3t would have 12

Bye. Jasen

Common is common why do you peeps insist on switching the common? DPDT is the way to go. Forget the ground or common switching, connect all grounds together. Case in point: in ole fashion VCR's the channel 3/4 modulator doesn't switch freaking ground, when it selects it's inputs.

You don't need that much switch, or the Y adapter. Each channel of your stereo signals only needs a SPST, and you can lose the Y adapter:

1A

| 0------ car stereo R 1B |

|

\\ 2C

2B

So, you'd look for a simple DPDT switch.

Cheers! Rich

29 Mar 2006

- 19 Mar 2006 ------------- 10 days.

Hmmm...

Lately, Rich, it seems your replies are often late enough that the subject matter has already been hashed over enough that your input is superfluous.

Are you aware of that?

The delay thing, I mean.

-- John Fields Professional Circuit Designer

Hey as long as google provides me with a reply button I could keep this thread going forever. Regardless of the time between posts.

And to sum up DPDT is the way to go. They didn't switch the grounds in the ole VCR's when switching inputs.

Yes, but I usually don't notice it until it's too late. I usually read all the way through NG, so the whole thing gets marked as read. The next day, something suddenly shows up, which I won't realize is a week or more old, because I haven't seen it or any part of the thread before.

I guess I'll chalk it up to a flaky server (Verizon ADSL), and pay more attention in the future.

Thanks, Rich

good come back, once you hit that post button it's all over the fat lady done sang.