The basics of creating a circuit powered by the Raspberry Pi.
These instructions are code-free. To see how you use code to control the LED, see the RaspberryPi/Blink page.
The Circuit Layout
The components of the circuit consist of the GPIO and its breadboard breakout cable; an LED; a resistor (anywhere from 200 ohms to 1K ohms); and the Pi itself.
To wire the breadboard, we'll hook up the LED to a pin on the GPIO that provides power. Any of the pins labeled 5V will do. This will give us a source of voltage.
Next, we'll run that voltage into the resistor, to step it down a bit and keep it from burning out our LED.
Then we'll run the resistor into the LED, to provide light.
Then we'll complete the circuit by hooking up the LED to ground.
Here's a fritzing diagram of the Hello World Raspberry Pi circuit:
The Final Circuit
The final circuit looks like this: