Never built a circuit? Perfect.

What electronics actually is

Electricity is a flow of charge — countless electrons drifting through a wire, like water through a pipe. Electronics is the craft of steering that flow to do something useful: light an LED, sound an alarm, spin a motor, sense the dark.

Three quantities describe every circuit you will ever build:

One equation ties them together — Ohm's law: current = voltage ÷ resistance, or I = V ÷ R. This is the tool you'll use in your first project. A red LED uses up about 2.0 V of the push, so a 220 Ω resistor sets the current to (4.5 − 2.0) V ÷ 220 Ω ≈ 11 mA — right in the LED's happy zone. Every project on this site shows its math like that, so you can see why the circuit works.

And one rule underneath it all: current only flows around a closed loop — out of the battery's + side, through your parts, back into the − side. No loop, no flow. Most "why isn't it working?" moments are a broken loop.

This is the complete Level 1 shopping list — about US $20–25 total: roughly a pizza night, wherever you live. Prices are rough local figures, not currency conversions — pick your region above if we guessed wrong. These are commodity parts sold worldwide: any electronics shop or large online retailer carries all of it, and hobby suppliers sell the same parts in friendlier packaging. Nothing here is brand-specific — a 220 Ω resistor is a 220 Ω resistor in every country.

• Solderless breadboard (half-size, 400 points)

  $3–6

  Your building surface. Parts push in and pull out — no soldering, nothing permanent, every mistake is reversible.

• 3×AA battery holder with wires + 3 AA batteries

  $2–4

  Your power source: 4.5 volts, which is enough for everything in Level 1 and safe to touch with bare hands.

• Jumper wire pack (male-to-male)

  $3–5

  The connections between parts. Get a mixed pack of 40+ — you will always want one more wire.

• LED assortment (5 mm, red / yellow / green)

  $3–5

  Your first outputs. The longer leg is the + side. Buy a multipack of 20+; you will burn out a couple while learning, and that is fine.

• Resistor assortment (must include 220 Ω, 1 kΩ, 10 kΩ)

  $3–6

  The parts that keep LEDs alive. Cheapest way is an assortment box of a few hundred — resistors cost about a cent each.

• Slide switches and push buttons (a few of each)

  $2–4

  Your first inputs: a switch that stays on, and a button that is only on while pressed.

Buying tip: assortment packs beat exact quantities. Parts this small are cheapest in bulk, and spares turn "I broke it" from a show-stopper into a shrug. Skip anything sold as a branded "beginner kit" with parts you can't name — you now know exactly what you need.

The safety rules (all four of them)

1. Battery packs only. Never wall power. Everything on this site runs on 4.5–9 V from batteries, which can't shock you. Mains electricity (the wall socket) can kill — it has no place on your bench, ever, and no TinyOhms project will ever ask for it.
2. Don't short the battery. A wire straight from + to − with nothing in between makes the maximum possible current. The wire and batteries get hot fast. If something warms up, disconnect first, ask why second.
3. LEDs always get a resistor. An LED barely resists current at all, so without a resistor it takes far too much and burns out — you did the math above.
4. Keep loose batteries and small parts away from little kids and pets. Especially coin cells — swallowed ones are a medical emergency.

Your first hour

1. Play in the Workbench — build the battery → switch → resistor → LED loop on screen and flip it on.
2. Build First Light for real — the same loop on your breadboard, with the full math and what-if challenges.
3. Break it on purpose — turn the LED around, pull a wire, swap the resistor. Predict what will happen before you look.
4. Pick the next project — every one opens in the Workbench first, so you can try it before you wire it.

From there, the ladder takes over: ten levels, each adding a few parts to the same box — sound, sensors, motors, chips, code, and eventually Wi-Fi. Nothing you buy today ever gets retired.