ADAFruit Lesson

• Current goes in one direction, from the anode (positive) to the cathode (negative)
• Electronic parts that only work in 'one direction' like this are called Diodes, thats what the last letter of LED stands for.
• LEDs that are 'backwards' won't work - but they won't break either
• LEDs are mostly used for two things: illumination and indication.

1.  Using a BROWN, BLACK, RED, GOLD resistor (1000ohms)

                  wire                                     wire     

GND > + | + > a | LED - + | resistor | - > 5V | + > a | LED - + | resistor

When lit, you will see the the diffused LED is softly lit, but the blue LED is harsh and ultra bright.

2.  The red red red(2200)  is the dimmest, then the brown black orange (1000), then the green blue brown(56) was the brightest.

3.  Changing the voltage to 3.5 and 5 V changed the brightness as well.  Clearly, the 5V was brighter than the 3.5 volt.  The 9V battery would have been even brighter.