All foundations
Unit 2 · The parts in your toolbox 6 minAge 8+

Capacitors, the tiny batteries

They hold electricity for a very short time, then release it.

Read first: Voltage and current

A capacitor is a small bucket for electricity. You can fill it up from a battery, then later, when the battery is gone, the bucket will pour its stored electricity back out.

Press Charge to fill it. Press Discharge to dump it through the LED.

Capacitors don't hold much — usually for less than a second — but that is exactly long enough to do useful jobs. They smooth out wobbly power, and they're the heart of timer circuits that can blink lights or beep buzzers on a schedule.

What does a capacitor do?

Now you understand…

  • Capacitors briefly store electricity.
  • Used to smooth power and to time blinks/beeps.
  • Some have polarity — match the + and − legs.

Now meet parts that let your circuit feel the world.