A diode is a two terminal electronic component that conducts current primarily in one direction asymmetric conductance. On a physical diode youll notice two terminals extending from a tin can shape in the middle. How To Test A Diode Using Analog And Digital Multimeter 2 Easy Ways To Tell Which Way Round A Diode Should Be How Does A Diode And Led Work Eagle Blog A diode is the most basic useful semiconductor device. How does the diode work . When a diode is forward biased so that electrons and holes are zipping back and forth across the junction theyre constantly combining and wiping one another out. It has two leads and acts as a one way gate for electric current. Diodes have a multitude of uses some of which well touch on later. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes a heated cathode and a plate in which