The Basics of Diodes

The Basics of Diodes

Diodes are an essential component for transforming AC to DC and protecting circuits by limiting voltage and current.diodes They are also used to emit light and create other colours of LEDs, as well as a host of other uses.diodes These are all made possible by a special type of doping to the PN junction of the semiconductor material used. It is important to note that diodes transmit current in only one direction and have polarized terminals, with the symbol pointing away from it indicating the anode end of the diode and the bar at the non-pointing end identifying the cathode. Current flows from the anode to the cathode with conventional forward bias, although a small amount can flow in the other direction in a reverse-biased diode due to the expanded depletion region.

The PN junction of a diode is formed from two types of semiconductor – silicon or germanium.diodes They are layered together to form a region on one side that contains negative charge carriers (electrons) and the other with positive ones (holes).diodes To make it so that these two regions do not contact directly, impurities are added to the n-side and p-side of the crystal which creates a third area between them that has neither electrons nor holes in it and is called the depletion region. When the diode is forward-biased, current flows through this region and creates light, and the frequency of the light depends on the type of doping applied to the n-p junction of the semiconductor.

A standard diode requires a precise amount of voltage to allow the current to flow through it, and until this threshold is reached no current can pass through it.diodes This is known as the forward voltage, and it varies only slightly with temperature.diodes

To use a diode, it must be connected to a power supply with the pointing end of the symbol (a) on the anode side and the bar on the non-pointing side (b) on the cathode side.diodes This ensures that the forward voltage of the diode is greater than -VBR, which is the voltage that prevents current from flowing in the opposite direction through the semiconductor, and this is why it is used to protect a circuit from overvoltage.diodes

Although it may not get as much attention as the transistor or integrated circuit, the diode is a vital part of most electronic devices and has many different applications.diodes Understanding the fundamentals of how it works is the first step to using it effectively in your circuit designs. If you want to learn more about how to do this, we recommend getting a good PCB design and analysis program such as Allegro from Cadence. This will enable you to experiment with the various different functions that a diode can offer and see how they can benefit your projects. Until next time, happy making! Robin Mitchell is an electronics engineer and writer from the UK who specialises in DIY and homebrew electronics. He writes articles, news pieces and projects for professionals and makers alike, and runs a small electronics business that produces educational kits and resources.