LED Flasher
Schematic: http://wild-bohemian.com/electronics/images/t-flash2.gif (the only difference is that I used two 22kΩ resistors instead of 100k) Parts list: LED x 2, 22kΩ x 2, 470Ω x 2, 10μF x 2, 2N3904 transistor x 2, SPDT switch x 1, 9V battery x 1.
Schematic: http://wild-bohemian.com/electronics/images/t-flash2.gif (the only difference is that I used two 22kΩ resistors instead of 100k) Parts list: LED x 2, 22kΩ x 2, 470Ω x 2, 10μF x 2, 2N3904 transistor x 2, SPDT switch x 1, 9V battery x 1.