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Project Notes

#244 DPDT Toggle Switches

All about double-pole, double-thow toggle switches.



A double-pole switch controls two circuits with a single action.

The double-thow nomenclature indicates that each circuit can be switched between two states.

Example Part: DPDT 2.54mm pitch Switch

Product example: 8x8mm Self-locking Push Button Switch

This is a convenient DPDT switch for PCB construction, having a pin pitch of 2.54mm. Unfortunately, the pin rows are only separated by two pitches (5.08mm), so it is one pitch short of a standard DIP layout. This means it cannot directly plug into a breadboard and span the centre line.


This particular part has the common poles on pins 3 and 6. Other parts may use a different layout; in fact I have come across an identically-looking part with a different (aligned) orientation of the poles. So it is always worth testing before assuming…


Test Circuit

The simple circuit described below demonstrates the DPDT toggle switch. The reverse polarities on each pole demonstrate the isolation.


  • when switch is “off” (i.e. not pressed), the red LEDs light on each pole
  • when switch is “on” (i.e. pressed), the yellow LEDs light on each pole






Credits and References

Project Source on GitHub Project Gallery Return to the LEAP Catalog

This page is a web-friendly rendering of my project notes shared in the LEAP GitHub repository.

LEAP is just my personal collection of projects. Two main themes have emerged in recent years, sometimes combined:

  • electronics - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting
  • scale modelling - I caught the bug after deciding to build a Harrier during covid to demonstrate an electronic jet engine simulation. Let the fun begin..
To be honest, I haven't quite figured out if these two interests belong in the same GitHub repo or not. But for now - they are all here!

Projects are often inspired by things found wild on the net, or ideas from the many great electronics and scale modelling podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.