Electronic – Make Bypass with Switches

We call it a "DPDT" (Double Pole, Double Throw).

While this won't work well in the case of your room lights it does show a means of lighting an LED using your switches. This could be used to drive an opto-isolator triac, etc., if you really had to use those switches.

^{simulate this circuit – Schematic created using CircuitLab}

Figure 1. An XOR configuration to control a small LED load using two SPST switches.

How it works:

• With both switches open both sides of the bridge rectifier are connected BATT+ by R1 and R2. The LED will not light.
• With both switches low both sides of the bridge rectifier are pulled low. The LED will not light but > 10 mA will flow in each switch for no optical benefit.
• If either SW1 or SW2 is closed current will flow through the LED.

^{simulate this circuit}

Figure 2. If SW1 is closed current will flow through R2, D3, LED D1, D4 and SW1.