The diode is one of the simplest forms of a semiconductor. At its most basic level, the diode allows current to flow in only one direction and blocks current in the opposite direction. However, there are numerous specialized adaptations of the diode that serve other functions as well. The LED (Light-Emitting Diode) for example is a diode that does as the name suggests, emits light when current passes through it. We will cover other types and their application in more depth later.
Some of the most important parameters of diodes to be aware of when selecting one are:
There are many other parameters to be concerned about depending on the application that are beyond the scope of this basic introduction.
As mentioned above, there are many types of diodes with numerous specialized characteristics. This section introduces a few of the most common types, and scratches the surface of their uses.
The semiconductor diode, sometimes also referred to as the silicone diode or a PN junction diode, is the most basic and fundamental of diodes. They will typically have a forward voltage of around 0.7V.
The Schottky diode is similar to the standard diode, but it has a lower forward voltage than the standard semiconductor diode.
The LED is probably the one most people are most familiar with. The LED emits a light when a voltage is placed across it. Like the standard diode, it allows current to flow in only one direction. LEDs will typically have a higher forward voltage than a standard diode.
The zener diode is a special type of diode that will maintain a constant voltage across it. Its breakdown voltage is such that reverse current is allowed to maintain the voltage. They can be useful in creating reference voltages or small power supplies.