What is a Transistor?

Honored with a spot on IEEE’s Milestone’s list, transistors changed the world of electronics, making smaller and cheaper electronics possible. Even though they control just about every modern circuit, transistors are often hidden within an integrated circuit, making them difficult to spot. Read on to learn more about transistors, how they are used and just what makes them so transformational.


Transistors actually have two different uses - they can act as an amplifier or a switch. These two applications can be visualized through two popular uses for transistors - hearing aids and computer chips.

Hearing aids have tiny microphones that pick up sound and turn it into electric currents which are then used by a transistor to power a speaker that amplifies the sound, making it seem louder to the hearing aid user.

As a switch, transistors are incredibly handy at switching small amounts of current into something that can power larger amounts of current. A typical computer chip contains hundreds or millions of transistors that can each be switched on or off individually in order to create logic gates.

The other important thing to know about transistors is that they are made of semiconductors. Semiconductors are materials that are not quite a conductor and not quite an insulator but have the ability to act as either. In transistors, a signal tells the device to either conduct or insulate, thus controlling the flow of electricity.


Field Guide to Transistors



To learn more about transistors, including their electronic symbol, their operation modes and the different types of transistors, view our Guide to Transistors.

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