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Transistor

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A transistor is a tiny part used in modern electronics.

Transistor symbol npn no circle
Transistor symbol npn no circle

It acts as a basic building block for almost all electronic machines. One important job of a transistor is to act as an amplifier. An amplifier takes a small signal and makes it much stronger.

Transistor as switch
Transistor as switch

Another job is to act as a switch for electrical signals. This allows electricity to flow or stop as needed. Because they are so small, many are tucked inside integrated circuits. They are considered one of the greatest inventions of the 20th century.

How does this little device work?

MOSFET Structure
MOSFET Structure

A transistor has at least three terminals, which are connection points. You apply a small voltage or current to one pair of these terminals. This action then controls the current flowing through a different pair. This is how it controls power or amplifies a signal. If the output power is higher than the input power, the signal grows.

Most transistors are made from very pure silicon. Some are made from a material called germanium. Some devices use one kind of charge carrier, while others use two.

The idea for these devices came long before they actually worked.

Julius Edgar Lilienfeld (1881-1963)
Julius Edgar Lilienfeld (1881-1963)

In 1925, a physicist named Julius Edgar Lilienfeld proposed a field-effect transistor. He filed patents in Canada and the United States in the 1920s. However, he did not build a working model at that time. In 1934, an inventor named Oskar Heil patented a similar device in Europe. It took many years to make the right materials to build them. Scientists needed much higher quality semiconductor materials to make the dream real.

The first working device was finally made in 1947.

Replica-of-first-transistor
Replica-of-first-transistor

Physicists John Bardeen and Walter Brattain built a point-contact transistor at Bell Labs. They used two gold contacts on a crystal of germanium.

Bardeen Shockley Brattain 1948
Bardeen Shockley Brattain 1948

William Shockley also worked with them and later invented the bipolar junction transistor. These three men shared the Nobel Prize in Physics in 1956. Between 1955 and 1960, Bell Labs also invented the MOSFET. This is the most widely used type of transistor today.

Transistors changed the world by making technology much smaller.

Philco Surface Barrier transistor=1953
Philco Surface Barrier transistor=1953

Before transistors, machines used vacuum tubes which were large and used much power. Transistors are much smaller and require less power to work. They allowed for the creation of tiny pocket radios like the Regency TR-1.

1957(Figure 9)-Gate oxide transistor by Frosch and Derrick
1957(Figure 9)-Gate oxide transistor by Frosch and Derrick

They also paved the way for calculators and computers. You can even find them in car radios, like the Mopar model from 1956. Today, they are in almost every electronic device you use.

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🖼️ Images & Media (28)
File:Transistor symbol npn no circle.svg
Transistor symbol npn no circle.svg
File:Transistor symbol pnp no circle.svg
Transistor symbol pnp no circle.svg
File:MOSFET Structure.png
MOSFET Structure.png
File:Julius Edgar Lilienfeld (1881-1963).jpg
Julius Edgar Lilienfeld (1881-1963).jpg
File:Bardeen Shockley Brattain 1948.JPG
Bardeen Shockley Brattain 1948.JPG
File:Replica-of-first-transistor.jpg
Replica-of-first-transistor.jpg
File:Philco Surface Barrier transistor=1953.jpg
Philco Surface Barrier transistor=1953.jpg
File:1957(Figure_9)-Gate_oxide_transistor_by_Frosch_and_Derrick.png
1957(Figure_9)-Gate_oxide_transistor_by_Fr...
File:Transistor Simple Circuit Diagram with NPN Labels.svg
Transistor Simple Circuit Diagram with...
File:Transistor as switch.svg
Transistor as switch.svg
File:NPN common emitter AC.svg
NPN common emitter AC.svg
File:BJT PNP symbol.svg
BJT PNP symbol.svg

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