LED wired in Parallel: same color LEDs (same voltage)

LED wired in Parallel: Different colored LEDs wired individually with resistors of appropriate value:

Notice that some LEDs of different color will need different voltages while other will not.

The ones that we have been using in class have all the same voltage. You can wire them as the first example using the same resistor for all of them.

LED wired in Series:

How to determine the value of the resistor/s needed for a given LED configuration:

1. Check on the data sheet of the LED the Forward Voltage (voltage). The ones that we use in class all need 2V

2. Check the voltage of  your power supply. We have been using 3V batteries so far. The Arduino puts out a 5V out of each digital pin.

3. Now that you have the above info input it in the resistor calculator to get the value of the resistor/s you need.

4. Led Calculator:

-For single LED

-For LED Array (multiple leds)