The Basics of Diodes

The Basics of Diodes

A diode is one of the most commonly used components in a circuit.diodes They can be found in everything from small-signal digital logic to high voltage power conversion.diodes Diodes do a wide variety of tasks, from protecting circuits from damaging current to converting AC signals into DC. They also help to steer current, making sure that the energy is used correctly and not wasted.

A simple two-terminal semiconductor device with a negative (cathode) plate and positive (+anode) semiconductor body, a diode permits electrons to flow from the cathode to the anode but not in reverse.diodes This property of asymmetric conductance allows them to protect circuits, limit current and convert Alternating Current (AC) into Direct Current (DC).diodes

When a diode is forward-biased (electronics jargon for "on"), the physical boundary between the n-type and p-type regions forms what’s called a PN junction.diodes The n-type and p-type semiconductor material is doped with impurities, which creates different types of charge carriers – holes on the N side and electrons on the P side.diodes The n-side and the p-side are separated by a region of un-doped silicon that is known as the depletion region.

The electrical potential on the P side is higher than the n-side, which makes it easier for electrons to cross over from the N side to the p-side.diodes When this occurs, the electrons fill the empty holes on the p-side, creating an electric field that prevents additional holes from crossing over from the N side to fill up the remaining holes. If the applied voltage on the n-side is higher than the threshold voltage, then the electrons will overcome the electric field and pass across the junction.

During this process, a small amount of electricity will be generated on the N-side of the diode.diodes This is due to the injected electrons and holes that are diffusing into this area. This is why it’s a good idea to apply an external voltage at the correct threshold level for optimum operation of a diode.

A diode’s on-off behavior, which can be a bit confusing when first learning about it, is the reason why engineers have chosen to depict them with an arrow that points against the direction of conventional current flow through a semiconductor.diodes It’s a common convention that’s been adopted by electronic schematics to show the permitted direction of current flow through a diode and to make it instantly clear to other engineers. However, it’s important to remember that this convention is just a convenient way of showing the on-off behavior of a diode. Its actual behavior is quite more complicated.