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Electronics => Beginners => Topic started by: msknight on June 21, 2021, 06:45:58 am

Title: Switch terminology
Post by: msknight on June 21, 2021, 06:45:58 am
I know what I'm looking for... I just can't work out the terms I need to find it.

On a joystick, I want a button/switch to mount on/in the joystick board, which allows me to invert an axis. Under normal operation, feed 1 goes to A and 2 goes to B. When "switched" feed 1 should go to B and 2 should go to A. Hence effective inverting the axis.

But I can't work out the terminology I need for that kind of switch. Any ideas please?
Title: Re: Switch terminology
Post by: Le_Bassiste on June 21, 2021, 08:04:59 am
DPDT does the trick of "swapping" two connections. (
Title: Re: Switch terminology
Post by: Ian.M on June 21, 2021, 08:11:21 am
You need a DPDT (double pole, double throw) switch, also known as 2P2T switch.  See for explanation of poles and throws.

Wire it as a reversing switch, i.e. cross link pole A NC to pole B NO, pole A NO to pole B NC, then run the pair of connections you want to reverse through the switch, on one side connecting both to the A and B COM terminals, and on the other to the two linked pairs of NO and NC terminals.

If you want to use a pushbutton it will need to be a latching switch, not a momentary one.
Title: Re: Switch terminology
Post by: jpanhalt on June 21, 2021, 09:38:48 am
There are 2 basic configurations of DPDT switches.  Some have a center position ("off").   Others just switch between the two options.  In addition, some hold the new position (i.e., there are 2 stable states) ; others are momentary on one state.

I suspect you want an on-on version.  Maybe this will do: (

EDIT: make that on/on "or on/mom"  (momentary)

If size is an issue. a single SPST momentary switch will probably be smaller and that could operate a DPDT relay.