Here’s an interesting clock circuit I just found out about. This one uses two NAND gates hooked up in a loop with a resistor and capacitor regulating the speed. Just change the value of the capacitor, and the clock should get faster or slower in response. The third NAND gate is only used to invert the output, otherwise the output would not be useful for anything. Higher cap values make the clock slower, while lower ones make it faster.
