Level: Next step

Turn the brightness up or down

A potentiometer sets the transistor's base voltage, so it dims the LED.

Open in the 3D builderReserve a kit
+−3V220Ω50%NPNNPN
RunningIt works!Current flows from the battery's + side, through your blocks, and back to −.
  • 1 LED lit

Try this

Click the potentiometer to turn the knob.

Blocks you need