Orienting a 3PDT

[hose]

[img]Hello- When looking a schematic or a picture of a layout that shows a 3PDT switch, how do you know how it is oriented so you can wire it the same? Is there a way to tell when looking at a schematic or a picture?

Thanks so much-

[R.G.]

I've always considered the physical placement of terminals on switches to be possibly random, and possibly making no sense at all. I started early in my career with using a meter to tell what connects to what, and it's worked well for a long time. It's much more definite than guessing.

The manufacturer's datasheet is better, and quicker, but I learned about switches before the internet.

What you do is to use a meter or other continuity checker to test which pin connects to which other pin, then flip the switch and see which pin connects to which other in the new setting. This will always, 100% of the time, work and produce something that you can use if you do it carefully and methodically, and you can use it when your connection to the internet is down, which can be a problem sometimes.

I've also found similar looking switches where the internal electrical connections were different.

[hose]

That is great advice! Thanks so much for taking the time to explain.

Best regards-

[MikeH]

Not exactly sure what the OP is asking, but I think it has to do with the fact that a 3pdt switch will often be drawn as 3 switches (each pole separately) on a schematic, not necessarily with a dotted line connecting them, and it can be tough to tell which of the throws on the switches correspond to one another?

The center of each pole is always the dot with the line/pointer thingy attached, and the other 2 dots are the outer throws.  If the schem is drawn right, all the pointer thingies for each pole should be pointing to the throws that are on the same side.  Or they will all be drawn so that the poles are all oriented the same, up-and-down wise.  So you might have one pole with the pointer pointing upward, and one with the pointer pointing downward, in which case the two that are pointed to (up and down) will be on the same side of the actual physical switch itself.  Clear as mud?

At least that is my vague understanding of it.

[Paul Marossy]

Assuming you are talking about the typical bypass switch, turn the 3PDT switch so you can see thru holes in the lugs. The middle row (from left to right) is the pole that is always connected, and that is switching between the upper and lower rows.


throw   throw    throw
#1         #2        #3

---      |    ---    |    ---     upper row (connected in switch position A)
         |           |  
         |           |    
---      |    ---    |   ---     middle row (always connected to something)
         |           |
         |           |      
---      |    ---   |   ---    lower row (connected in switch position B)


Think of it as three SPDT switches side by side. That's basically all it is.

[Hides-His-Eyes]

I felt they were arranged "wrongly" but i'm just about used to seeing sets through holes instead of down lines.

[Paul Marossy]

I felt they were arranged "wrongly" but i'm just about used to seeing sets through holes instead of down lines.

Like RG said above (and what I sometimes need to do), when in doubt about what poles are connected to what in any kind of switch, use a continuity checker. That makes simple work of it.

A couple weeks ago I reworked the pickup switch in one of my guitars. I used one type of 5-way switch that was different from what came in the guitar in terms of where you connect the wires to it. One has all eight of the terminals in a row, and the other has four terminals opposite another four terminals. I intially had it wired half-wrong. I would have never figured it out without a continuity checker at my disposal. It also saved me a whole lot of aggravation. 

[hose]

I was referring to the stomp style 3pdt switch that has been rightly identified. Mostly when looking at a "real" picture of the inside of a effects unit, it is hard to tell which way the switch is turned (or oriented). Most specifically in building this: http://www.fulltone.com/PDfFiles/AB_switcher.pdf

How would one know which way the switch is spun or turned?

Again, that for taking the time with a newbie. I do very much appreciate your time.

[MikeH]

The switch is a mirror of itself.  As long as you have the poles aligned properly (with the lugs longways from side to side) then it doesn't matter which side is a the top.  The switch is symmetrical from top to bottom.

Like this:
             _  _  _
             _  _  _
             _  _  _

Not like this:

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