How It Works

• The "diode" part of a light-emitting diode is a component that allows electrical current to flow in only one direction. A diode has two electrical leads: the anode and the cathode. The anode is connected to the positive side of a power source such as a battery, and the cathode is connected to the negative side. Otherwise, the diode won't work correctly.
  
  To avoid damaging an LED, the voltage differential applied to the anode and cathode must be relatively small. A typical LED will light up at between 2 and 5 volts and have a current draw of about 20 milliamperes.
  
  

Creating an LED Light

• Because of an LED's minimal power requirements, creating an LED light is relatively simple. You will need two electrical wires (preferably small-gauge wires, between 20 and 28 gauge, stripped of insulation about an inch at each end), an LED, and two 1.5-volt batteries. Batteries of the same type that can be connected in series easily, such as two AA cells, are preferable.
  
  Place the batteries in series (where one of the batteries has its positive terminal connected to the negative terminal of the other battery). Connect one end of the first wire to the positive terminal of the first battery and the other end of the wire to the LED anode.
  
  Connect one end of the second wire to the negative side of the second battery and the other end of the wire to the LED cathode. The completed circuit will cause the LED to light up.
  
  

Caution

• Since LEDs are low-power electronic devices, excessive voltage can harm them. Check the specification sheet of the diode you plan to use to ensure that your electrical circuit will not overload the LED. An LED that has too much voltage applied to it will light up brightly for a few moments and then burn out, melt or sometimes explode.