DPDT Switch: Synchronized Contact Selection

A double-pole double-throw (DPDT) switch operates two SPDT contact sets with one control. Pole A switches a 5 V supply, and pole B switches a 3.3 V supply. Each output has a separate 1 kΩ load to ground. The dashed link between the blades represents their shared mechanical control.

Try it

1. Click Run simulation.
2. Click either blade of SW1. Both poles transfer together, and all four voltage traces update while the simulation continues.
3. Click SW1 again to restore the starting position.

What to look for

Output	NC, initial	NO, after click
VANC (blue)	About 5 V	About 0 V
VANO (red)	About 0 V	About 5 V
VBNC (teal)	About 3.3 V	About 0 V
VBNO (orange)	About 0 V	About 3.3 V

The selected A load draws about 5 mA; the selected B load draws about 3.3 mA. The poles have separate contacts and share the ground return in this example.

Closed contacts use 100 µΩ and open contacts use 100 MΩ, giving small leakage voltages on unselected outputs. The model transfers both poles together without contact bounce or switching delay.