DC Fundamentals

2-Way Staircase / Three-Way Hallway Switch Wiring Simulator

Interactive electrical wiring trainer showing how two SPDT switches linked by traveler wires control one lamp from upstairs or downstairs.

Speed
Classic electrical wiring puzzle! Flip EITHER upstairs switch (SW1) OR downstairs switch (SW2) to turn the hallway lamp ON or OFF from both ends.
ā— CH1: CH1
ā— CH2: CH2

Engineering Theory & Mathematical Model

Lamp = XNOR(SW1, SW2)

Known as "2-way switching" in IEC/UK terminology and "3-way switching" in North American NEC wiring, two Single-Pole Double-Throw (SPDT) switches connect via a pair of parallel traveler conductors. Flipping either switch selects the opposite traveler rail, implementing hardware XNOR logic so either end toggles the light state anytime.

Interactive Lab Procedure

  1. Click "Floor 1" switch (SW1) to light the Hall Lamp and watch yellow current particles travel along the active traveler wire.
  2. Now click "Floor 2" switch (SW2) to turn the lamp OFF from the opposite end of the hallway!
  3. Click "Floor 2" again to turn it back ON via the alternate traveler rail.

Technical FAQ

What is the core governing formula for 2-Way Staircase / Three-Way Hallway Switch Wiring Simulator?

Lamp = XNOR(SW1, SW2) ā€” Known as "2-way switching" in IEC/UK terminology and "3-way switching" in North American NEC wiring, two Single-Pole Double-Throw (SPDT) switches connect via a pair of parallel traveler conductors. Flipping either switch selects the opposite traveler rail, implementing hardware XNOR logic so either end toggles the light state anytime.

Can I modify component values and rewire this circuit live?

Yes! The schematic above runs a live MNA SPICE engine. Click any part to adjust parameters, add or delete wires and components, and click Share URL to save your custom topology.

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