Meet the circuit

We are making a basic circuit of one LED, a resistor and a battery.

LEDs

One important thing to remember about LEDs is that they have a polarity, or direction in which they must be placed in order to work in a circuit. If we place the LEDs backward, they won’t light up. How do we know the orientation of an LED?

LEDs have two legs, or leads, which are different lengths. The longer lead is known as the anode, the side of the LED that we will connect to power. The shorter leg is called the cathode, which will be pointed away from our power source. If you place the LED in backward, it won’t light up but it also will not damage anything in your circuit.

However, as a maker, you should not blindly trust leg size, as somebody might have previously clipped the legs!