START A BIT

Learn the basics

Circuit diagram

The wiring the way engineers draw it: every line is a wire, every part has a symbol. Read one in a book or on a website and build it.

One LED on pin D2 drawn twice: with a wire back to GND, and with two GND symbols

Circuit diagram

The wiring picture shows where every wire goes on your table. A circuit diagram shows only what is connected to what: every line is a wire and every part has its own symbol. Engineers all over the world draw circuits like this, so a diagram from a book or a website works for you too.

Follow a line from a pin: everything on that line is connected. All GND symbols are connected to each other, so the two drawings are the same circuit.

More: the symbols, and from the diagram to the breadboard
The symbols: wire, joined wires with a dot, crossing wires, resistor, the US resistor drawing, LED, button, buzzer, knob, ground, power, battery
  • A dot joins wires. Two lines that cross without a dot are not connected.
  • Boxes are boards. A box with pin names is a board or a module, like the Arduino or a sensor. Its pins have the same names as on the real board.
  • The triangle of the LED points the way the current flows, from the long leg (+) to the short leg (−). The short leg goes to GND.
  • Two resistor drawings. Europe draws a box, the USA a zigzag. Both mean the same part.

From the diagram to the breadboard: take one line at a time, start at a pin of the board, and put a tick on the line when its wire is in. When every line has a tick, the circuit is complete.

Try it: open the circuit diagram under "Wire it" in a project, cover the wiring picture, and wire it from the diagram only.