Need DPDT Schematic Symbol Example

[Steve Mavronis]

I need an schematic example to follow so I can add a true bypass footswitch between the input and output jacks , along with an 'on' status LED to my circuit using this DPDT symbol:



I usually see it represented either as several separate switches (SW1a, SW1b, etc.) or a graphic like these showing the actual switch pinout:



I guess it's valid to use a graphic that means the same thing but I want to stick with actual schematic symbols in my circuit diagram. Also what is the difference between a DPDT and 3PDT as far as which is better to use?

[JKowalski]

On the schematic format the wires on the left are the cent of the poles, they are always connected to the moving part in the middle and alternate between the parts on the right.

On the picture format the "always connected" part would translate to the middle of one of the columns of three, with the two parts on the right of the schematic version being the lugs above and below it.

A 3PDT simply has one more pole then a DPDT, (p stands for "pole" t stands for "throw, so Triple Pole, Double Throw and Double Pole, Double Throw) so this would give you one extra totally isolated switch portion that you can use the switch an LED on and off.

In the schematic format a 3PDT would be the same except you add another system of permanent left part + two right parts, on the picture it would just be another column added on.


Look at tonepad schematics for an example of the DPDT on a schematic, I believe they all have it.