switchestoggle switch
I need a toggle switch which allows me to switch the poles of two separate single-pole-double-throw switches together. It would work like the diagram below. Note that the dotted line represents a physical connection not an electrical one.
I need to find one online (for UK shipping). What are they called?
You can implement this with semiconductors provided the power supply to the circuit stays on all the while you want to have the transistors conducting current. This problem is also much easier to solve if you design for the current flow through the switches to always be the same direction.
Let's say that you design for 12V coming into the C (common) terminal of each "switch" and the NC (normally closed) and NO (normally open) "connections" will always be used to gate power to a ground referenced load from the incoming 12V.
For each pole you will need two FETs driven from a pair of control signals that are logically inverted from each other. You drive one FET ON while the other is OFF and flip the states when the "switch" changes state. In this 12V design you may find it easiest to use a P-FET since turning on the FET works nicely by pulling the FET gate to GND with the control signal. (If you use N-FETs it is necessary to provide sufficient gate drive above the 12V level signals that you are trying to switch). The two FET drive signals can derive from a single control signal by adding an inverter within the path to one of the FET gate drives.
Example Schematic - Note that you have to select the appropriate P-FET per your requirements.
For 4 places see below: -
simulate this circuit – Schematic created using CircuitLab
For 3 places remove one of the two pole switches. For more than 4 just keep repeating the 2 pole switches.
Best Answer
We call it a "DPDT" (Double Pole, Double Throw).