PN Junction Diode
- a summary or tutorial giving the essentials or basics of the PN junction diode, including its applications, specifications and parameters and its operation.
Diode types and topics include:
• Diode types overview • PN junction diode • Diode specifications • Gunn diode • IMPATT diode • Laser diode • Photo diode • PIN diode • Schottky barrier diode • Step recovery diode • Tunnel diode • Varactor diode • Zener diode • Light emitting diode, LED
The term PN junction diode is normally reserved for what may be called the basic form of diode, although in reality the term applies to virtually any form of semiconductor diode. The PN junction diode gains its name from the fact that it is formed from a semiconductor PN junction and by its nature it only allows current to flow in one direction. However the PN junction diode also has other properties that can be used in many other applications. These range from light emission to light detection and variable capacitance to voltage regulation. Many of these types of diode are described in other pages on this section of the Radio-Electronics.Com website.
The basic form of PN junction finds many uses in electronics circuits. The standard PN junction diodes are available in a variety of forms. They are mainly manufactured from silicon, although germanium diodes are also available. PN junction diodes can also be manufactured from other semiconductor materials, but these are generally specialised diodes used for particular applications.
The basic PN junction diodes are able to perform a variety of roles in electronics circuits. These range from applications as small signal diodes, to switching, to those required in applications such as power supplies as high current or high voltage rectifiers.
PN junction diode circuit basics
As the name indicates a diode has two terminals. These are referred to as the anode and cathode. When in circuit, the current flow (conventional current flow) is across the PN junction diode from the anode to the cathode. As the diode is a one way device, current is inhibited from flowing in the other direction.
The PN junction diode may be looked at as the basic or entry level diode. Nevertheless the basic PN junction diode is widely used in many applications from being a signal diode and detector, through being a clamp diode or transient suppressor across inductors or relay coils, through to high power rectification. In all these applications the basic PN junction diode is able to provide a very useful service. As a result, these diodes are use dry the million each day.
By Ian Poole