Circuit bench

Build beginner circuits on a virtual snap-together bench: 21 guided labs with lamps, motors, LEDs, sound and light sensors. Free, no sign-up, phones first, works offline.

Getting started · Parents and teachers · About

The labs

Closed path

  1. Lamp and switch: Lamp lights only while switch is closed.
  2. Motor and switch: Shaft spins when switch closes. Fan seated on the three-tab top.
  3. Lamp and fan in series: Both run. Remove fan: lamp dims as stall current falls.
  4. Lamp and fan in parallel: Motor starts quicker than lab 5. Lamp brightness stays put when the fan comes off.
  5. Fan launch: After high RPM, opening the switch lets the blade rise.
  6. Weaker launch: Height drops versus lab 11.
  7. Two-speed fan: Held press = faster shaft.
  8. Fuse pull: Removing the fuse span opens every path.

Light and polarity

  1. Limited LED: LED lights. Coach fires if limiter is missing.
  2. One-way light: Dark when reversed. Polarity marks visible.
  3. Conduction probe: Metal sample lights the LED. Plastic does not. Finger is too resistive at 3 V.

Melody window

  1. Sound wakes the melody: After the boot phrase ends, a tap on the piezo starts music again.
  2. Quieter plate: Same ticket as 3, but quieter.
  3. Melody doorbell: Release does not cut the phrase.
  4. Held alarm: Release mutes immediately.

Alarm pass

  1. Siren ticket: Sweeping siren.
  2. Burst ticket: Shorter, sharper phrase.

Effects station

  1. Effects deck: Each press moves on to the next of the eight sounds.
  2. Light is the switch: Cover the light sensor and it goes quiet. A dark room does the same.
  3. Alarm plus effects stack: Pressing and covering the sensor each change the mix.
  4. Stripe card: Each dark bar that passes moves the module on one sound.

Questions

What is Circuit bench?
A free, browser-based bench for snap-together beginner circuits. Children place parts on a virtual base plate, press Run, and watch lamps glow, motors spin and speakers play. 21 guided labs build on each other, each with one clear thing to notice.
Who is it for?
Curious children of about 8 to 12, and any beginner. Parents and teachers get a guide with questions to ask. Most labs take five to ten minutes.
Is it free? Does it need an account?
It is free, with no sign-up, no accounts and no ads. Progress stays in the browser on the device.
Does it work on phones and offline?
It is built for phones first and works on tablets, laptops and desktops. Add it to the home screen and it opens like an app. After one visit it works offline.
What does it teach?
Closed circuits and switches, series and parallel, motors and inertia, LED polarity and resistors, conductors and insulators, sound modules and control pins, and light sensors. The simulation is honest, so what children learn carries over to real parts.
Is it safe?
The bench is virtual, so nothing can hurt anyone. It still teaches real habits: it warns about short circuits, shows an LED that would burn out without its resistor, and flags labs with moving or loud parts.
Who made it?
Architected with Grok and ChatGPT, then coded by Claude. With Dale.

Built by Grok · ChatGPT · Claude, w / Dale.