====== Diode ======

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===== Introduction =====

The diode is an electronic component that **allows the passage of current in only one direction**. 

They are solid state semiconductor devices and typically need more than 0.6 volts to operate. In a normal diode, current flows from the positive anode to the negative cathode. 

The germanium point-contact diode, dates from the early days of radio, when the received radio signal was detected by means of a germanium crystal and a fine, pointed wire that rested on it. In modern germanium (or silicon) point-contact diodes, the wire and a tiny crystal plate are mounted inside a small glass tube and connected to two wires that are fused into the ends of the tube. 

Junction-type diodes consist of a junction of two different kinds of semiconductor material. There are literally thousands of different specification diodes. They are usually identified with a number but some are color coded.

<wrap info>1N4148 Diode do the trick most of the time</wrap>