Lab46 Wiki

When you pick up the LED, you will notice that one leg is longer than the other. The longer leg (known as the ‘anode’), is always connected to the positive supply of the circuit. The shorter leg (known as the ‘cathode’) is connected to the negative side of the power supply, known as ‘ground’.LED stands for Light Emitting Diode, and glows when electricity is passed through it.

LEDs will only work if power is supplied the correct way round (i.e. if the ‘polarity’ is correct). You will not break the LEDs if you connect them the wrong way round – they will just not light. If you find that they do not light in your circuit, it may be because they have been connected the wrong way round.

connect one side of the switch to an input pin on the Raspberry Pi. The other side of the switch we connect to 3.3V on pin 1 using a resistor. The resistor is used as a current limiting resistor to protect our input pin by limiting the amount of current that can flow.