1N4001 Diode

Image courtesy of Adafruit

Diodes are two-terminal passive devices that allow current to flow in only one direction. They are frequently used to protect from voltage spikes, to protect I/O pins, to form rectifiers, and more.

Download the 1N4001 Diode Datasheet (PDF)

Buy 1N4001 Diodes at Amazon, Adafruit, or SparkFun.