Build Guide · Fundamentals

A Complete Circuit

The simplest possible build: power a light, then add a switch to break the loop. Master this and every other guide is just more of the same.

Difficulty: BeginnerBuilds on: nothing — start hereLesson: read the theory →

What you’re building

Power through a maintained switch to a light, and back. The switch breaks the loop.

Add the three parts
From the left palette, click Power Source, then Single-Pole Switch, then Light. Each appears on the canvas — drag them apart so you have room to wire (drag from the body of a device, not its terminals).
Set your voltage (optional)
Click the Power Source to cycle through voltage systems. For this simple circuit any single-phase setting (like 120V) is fine. The Light just needs the loop completed.
Wire the hot leg through the switch
To wire, click the first terminal (it highlights), then click the second — a wire connects them. Click empty space to deselect. Connect power out to one side of the switch, then the other side of the switch to the light.
Power Source L1 → Switch (left terminal)
Switch (right terminal) → Light (left terminal)
Complete the loop back to the source
Now bring the other side of the light back to the source neutral/return. This closes the loop — without it, nothing happens.
Light (right terminal) → Power Source N (neutral/return)
Energize and flip the switch
Click Energize at the top. With the switch closed the light glows. Click the switch to open it.

Flip the switch open — the light goes out (you broke the loop).
Flip it closed — the light comes back.
Try removing the return wire while energized: the light dies even with the switch closed, because the loop is broken.

Tip: If the light never lights, check that one side traces back to L1 and the other side back to the neutral/return. A load needs both.

Follow the steps above with the trainer open in another tab.