Diode

•A diode is a 2 lead semiconductor that acts as a one way gate to electron flow.

– Diode allows current to pass in only one direction.

•A pn-junction diode is formed by joining together n-type and p-type silicon.

•In practice, as the n-type Si crystal is being grown, the process is abruptly altered to grow p-type Si crystal. Finally, a glass or plastic coating is placed around the joined crystal.

•The p-side is called anode and the n-side is called cathode.

•When the anode and cathode of a pn-junction diode are connected to external voltage such that the potential at anode is higher than the potential at cathode, the diode is said to be forward biased.

–In a forward-biased diode current is allowed to flow through the device.

•When potential at anode is smaller than the potential at cathode, the diode is said to be reverse biased. In a reverse-biased diode current is blocked.