Quick 3p4t Question!

[stonerbox]

Hi!

I'm trying to use a rotary switch for input capacitors. I got a 3p4t switch at my disposal and I have noticed something strange. It got 8 positions on the rotary and it repeats it self after four turns. At the fifth turn it sends the signal back to pin 1 again and starts all over. Why is this?

[R.G.]

It's common for some rotary switches to have a continuous-rotation mechanism. This is further subdivided into those that arrange the internals so there is  "repeat" if it uses a full half-rotation, and those that for one reason or another have stops. The "stops" version is further subdivided into those that have fixed stops and those that have adjustable stops. Some rotary switches of the 3P4T type can be "stopped" at 3P2T and 3P3T by moving the adjustable stops.

You happen to have one of the continuous-rotation-echoing variety. The world of mechanical switches is wildly variable, sometimes subtle, and often perverse.

[bluebunny]

There's a washer with a single tooth that fits back into the switch.  This stops the switch spinning forever.  (It's actually intended to turn a 3P4T into a 3P3T when you only have use for 3T, say.)  Has someone nabbed the washer?

Edit: what R.G. said too!  (simul-post)

[stonerbox]

Did not realize there were holes up top and a washer w/ stop lug on it, until now.  Thank you guys, you saved my evening!

[bluebunny]

Yeah, unless it falls out, it does a good job of concealing its purpose!