Guide to leds

In this instructable i will show you how leds work the different types and cool projects 

Step 1: How leds work

Leds work when a semi conducter is joined with 2 terminals + &- p + n positive and negative gives light beams here is a picture to explain further.

Comments

[synthblade]

I find this to be lacking some information. Assume people who visit here don't know what arduino is. Explain where + & - belong in some of your examples. Lastly, recommend some places to purchase LED's, batteries, and wiring/switches used in above examples.