Here is shown a Do It Yourself kit for making silicon atoms and crystals to demonstrate how semiconductor crystals work and how they are used to make transistor switches.
Depicts the step-by-step process by which the transistors of an integrated circuit are made.
An LED is the device shown above. Besides red, they can also be yellow, green and blue. The letters LED stand for Light Emitting Diode.
full guide by Cyber Circuits.
insight into Ohm's law, Kirchoff's law, LED calculations and voltage dividers
A large reference of schematic symbols and brief explanations of each.