What it is, how it works and applications

Among the hundreds of electrical and electronic inventions, there are some that stand out from the rest for their unique capabilities and powerful functionality. This is, for example, the case of a small component known as a transistor. In order to have a clear idea of ​​its importance, there is currently no electronics that does not have at least one transistor in its composition.

Therefore, it is essential that an electronics or electronics expert knows the important details about this component that is so used. That’s why we’ve gathered here what it is, how it works and how to use a transistor properly.

So what are you waiting for? Check it out now and end your doubts about the device!

Transistor: what is it and what is it for?

Credits: Engineering Mentality Channel / YouTube (2022)

A transistor is a semiconductor device created with the aim of exchanging or amplifying electrical energy, as well as electronic signals. Its name comes from the English term transfer resistor.

That is, he it acts directly with the intensity of the electric current present in the electric circuit, it is possible to increase or completely stop the passage of that current.

When used for amplification, transistors accept a low electrical input current and produce a high electrical output current. So, in this case, the transistor increased the intensity of that current and left it higher than when it entered.

When used to prevent the passage of current, the transistor takes on the function of a switch where it has the ability to throttle the electrical current, so that it can be turned on or off.

And this whole process happens in the blink of an eye, so fast that it has turned the transistor into an essential device in the composition of electronic chips, for example, widely used mainly in computers, laptops and smartphones.

In general, transistors on the market are made of silicon or germanium, but it is possible to have semiconductors that use other types of materials in their composition.

How does a transistor work?

Credits: Canal Manual do Mundo / YouTube (2022)

As explained above, a transistor has the ability to control electric current (ie, release or prevent the passage of electrons). But while all transistors perform this function, each type of transistor will perform it differently. And that’s why you can find different types of transistor configurations on the market.

Some transistors have the ability to be so small that when used in smartphones they can even control electrons individually, while when used in electronic chips (such as computer processors) they can contain up to 30 billion transistors on a single chip.

To achieve the expected result the transistor uses a doping processwhere silicon atoms are transformed into gallium, phosphorus, etc. Following this structure, there are only two types of doping that can be found in transistors, namely: P-type (positive charge) and N-type (negative charge).

When P-type doping is used, atoms are added that can cause electron deficiency. In type N, the opposite happens, where atoms are added to silicon, which can generate excess electrons.

Main transistor configurations

Credits: VirtualBrain / YouTube Channel (2022)

There are currently several main configurations that can be used in transistors and each has its own unique characteristics. These settings are:

Field Effect Transistor (FET)

Activated by an electrical voltage, the FET has the ability to cut off or amplify the electrical voltages present in the circuit. It also has three layers with semiconductor powers. Another positive point of the field effect transistor (FET) is its low cost and ease of manufacture, making it a widely used option mainly in electronic chips.

Junction transistor

Also formed by three layers composed of pure silicon with different levels of doping, the junction transistor has two ways of stacking its layers (npn and pnp). One of them, for example, uses hole conduction and is now called a bipolar junction transistor. In the PNP model, transistors have two P layers and a middle N layer, which is the inverse. In the NPN model there are two N semiconductors and an interlayer P.

Metal Oxide Semiconductor Field Effect Transistor (MOSFET)

This is probably the most popular of the other transistor configurations, and has become one of the most widely used. Using it, it is possible to find two different categories that have two more categories in them. The former are divided into N-channel and P-channel, which are also divided into Depletion MOSFETs (with connected substrate, drain and source terminals) and Enrichment MOSFETs (with separate substrate, drain and depletion terminals).

Silicon sandwich transistor

Finally, the last most common configuration that can be found in transistors is a silicon sandwich, composed of two layers of silicon, where one will contain P-type doping and the other N-type, commonly known as a diode. This is because it only allows current to flow in one direction.

Significance and production of transistors

Considered one of the greatest inventions of the 20th century, the transistor has today become an indispensable component in any type of electronics. For this reason, it is necessary that its production takes place on a massive scale, in order to produce the largest amount of transistors in the shortest possible time. In turn, this process has high automation that can create low costs in the production of these components.

Furthermore, this mass production can generate individual transistors (ie, packaged alone) or in an integrated circuit (together with resistors, diodes, capacitors, etc., so that there is a complete electronic circuit).


Nowadays, there are almost no computers or microphones that are not manufactured with a common component: the transistor. Created in the 20th century and considered one of the greatest inventions of that time, transistors have the function of amplifying or interrupting the passage of electric current.

With its fast activation, the transistor has become an ideal item in the production of electronic chips, which are widely used in computers and smartphones (in processors, for example). Due to its amplification capability, it is an indispensable component in microphones and other similar items.

The transistor, which is generally found on the market based on pure silicon or germanium, can have different configurations, which will give different results. The most common are the field effect transistor (FET), junction transistor or bipolar junction transistor, metal oxide semiconductor field effect transistor (MOSFET), silicon sandwich transistor.

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