For this activity, you'll design a simple LED circuit. To complete this, you'll need: 

  • LEDs
  • Resistor
  • Battery
  • Wires

(You can get all of these in the lab!)

The first step is to choose how many LED's you want to light and their type (color, brightness). With this simple circuit you will be somewhat limited by the amount of voltage (V) that can be safely provided for your project.

Calculate the amount of voltage you need from your power supply.

  • Red or Orange: 2.0 V
  • Yellow 2.1 V
  • Green 2.2 V
  • True Green, Blue, White 3.3 V
  • Blue (430 nm) 4.6 V

Say you want to have 3 Red LED's in your circuit. So, 3 x 2.0 = 6V, needed.

Calculate the required LED resistor value.

LED's cannot be connected directly to the battery or power supply. The LED will be instantly destroyed because the current is too great. The current must be reduced. The easiest way to do this is by using a resistor.

First, draw out your circuit diagram, using the symbols you saw in the previous pages. Then, wire your circuit together, creating either a parallel or series circuit.