How Does a Transistor Work?

How Does a Transistor Work?

The transistor is a semiconductor device that can control the flow of current and amplify or switch other electronic currents. It is widely considered one of the greatest inventions of the 20th century because it allowed electronic devices to be made much smaller and at far less cost than previous generations of technology. The transistor is found in most modern electronic devices including microchips, computers, cell phones, and other devices.

The basic working principle of a transistor involves a small current flowing through the base terminal controlling a much larger flow of electrons between the emitter and collector terminals. The base terminal is the middle terminal that connects to both the emitter and collector and is very thin and lightly doped. The emitter terminal is the positive lead and the collector terminal is the negative lead of the transistor.

When a transistor is not being used, the voltage across the base-emitter junction (VBE) and the collector-base junction (Vcb) are both negative. This is called cutoff mode and is an example of how a transistor works in a very simple way. If a transistor is in cutoff mode, a very small amount of current must be flowing through the base to make it work.

In order for a transistor to operate normally, the VBE and Vcb must both be positive. If they are not, the transistor will never turn on because it will be in cutoff mode. This is the simplest way to explain how a transistor works, but it's important to remember that there are a lot of complex quantum physics level things going on inside a real transistor.

A transistor is created by stacking three different layers of semiconductor material together. Some of the layers have extra electrons added to them (a process called doping), while others have holes added to them (the absence of electrons). The layer that has the extra electrons is referred to as an n-type semiconductor, while the layer that has the holes is referred to as a p-type semiconductor. The n-type semiconductor is then layered on top of the p-type semiconductor. This creates a P-N junction that can conduct current when a positive voltage is applied to the junction.

If a negative voltage is applied to the p-side of the P-N junction, it will widen the depletion region and prevent electrons from flowing across it. This causes the junction to be in reverse bias and the current through it will be very low until a certain point is reached at which time the current will rapidly increase.

The first practical transistor was built in 1948 by William Bradford Shockley, John Bardeen, and Walter Houser Brattain. They received the 1956 Nobel Prize in Physics for this work. Since then, the technology has evolved and improved to where it is today. Almost every electronic device has a transistor, and the world would not be what it is today without this amazing piece of technology.