Ohmsville is live
The early-80s spring-terminal electronics lab, running in your browser. Here is what is in the box, who is teaching, and how the shelf is stacked.
If you had one of those Radio Shack "30-in-1" kits as a kid, you know the board: a sheet of cardboard with parts glued down and a numbered spring next to every lead. You clipped wires between springs 1 and 5, 6 and 28, and something lit up, or buzzed, or didn't. That board is now live at ohmsville.com. Nothing to install.
The kit
The board is a real circuit simulator, not a picture of one. The standard set on springs 1 to 45 is a 9 V battery, seven resistors, a 10 kΩ pot, four capacitors, a red and a green LED, two NPN transistors, a pushbutton, a slide switch, an 8 Ω speaker and a CdS photocell. LEDs glow the right brightness for the current through them. The speaker sings when a square wave reaches it. Put a 100 Ω straight across the battery and it smokes, and you get to reset it. Hover any part and you read its live volts and amps. A drawer underneath holds spare parts, and every part can be moved to another slot or put away.
The teacher
A shop teacher sits in the manual. Ask why the flasher flashes and you get plain words first, the proper term second. The teacher also has hands: it can clip wires, turn the pot, hold the button and load a circuit in front of you, then break it on purpose to show you a failure. "Check my build" has the teacher read the live board and grade what it finds, not just whether your wires match a list.
The classroom
Beside the bench there is a class, five units and twelve short lessons, from what electricity is to reading a schematic. Each lesson has a live demo on the bench and a two-question check the teacher grades. Nobody makes you take it.
The Ladder
Projects are stacked as levels, the way the real kits grew from 30-in-1 to 100-in-1. Level 1 is First Light, five experiments from one glowing LED to a light-controlled tone. Pass three and Level 2, Timing & Control, opens, then Level 3, Sound & Sense. Each level unlocks more drawer parts. A Builders' Club code saves your progress and your named builds, and passes earn stickers on the card.
Go clip some wires. The manual is right there when something doesn't light.