Transistors

What is a transistor?

Transistors are the key building blocks of integrated circuits and microchips. They’re basically microscopic electronic switches or amplifiers. As such, they control the flow of electrical signals, enabling the chip to process and store information.

A transistor is usually made from silicon or another semiconductor material. The properties of these types of material are in between those of an electric conductive material (like a metal) and an insulator (like rubber).

Depending on the temperature, for example, or on the presence of impurities, they can either conduct or block electricity. This makes them perfectly suited to control electrical signals.

A transistor consists of three terminals: the base, collector, and emitter. Through these terminals, the transistor can control the flow of current in a circuit.

How does a transistor work?

When a small electrical current is applied to the transistor base, it allows a larger current to flow between the collector and the emitter. This is like a valve: a little pressure on the base controls a much bigger flow of electricity.

• If there is no current at the base, the transistor acts like a closed switch. No current flows between the collector and emitter.
• If there is a current at the base, the transistor opens up. Current flows through.

This ability to control electrical current allows transistors to work as a switch (switching things on and off) or as an amplifier (making signals stronger).

• As a switch: Transistors can rapidly turn on and off, representing binary states (0 and 1) that form the foundation of digital computing. When a small voltage is applied to the base terminal, it allows a larger current to flow between the collector and emitter, switching the transistor ‘on.’ When the voltage is removed, the current stops, and the transistor turns ‘off.’
• As an amplifier: Transistors can also be used to boost weak electrical signals. A small input signal applied to the base can control a larger output signal between the collector and emitter, amplifying it. This is essential in devices like radios, televisions, and audio systems, where signal amplification is necessary for proper operation.

In digital electronics, transistors are used in large numbers to build logic gates. These form the foundation of computer processors. By switching on and off very quickly, transistors help process the binary code that computers use to operate.

What types of microchips exist?

The first transistors

The history of transistors starts in the 1940s. Scientists were looking for better ways to control electrical signals in devices like radios and televisions. At the time, these devices used vacuum tubes, which were big, used a lot of power, and often broke.

In 1947, three scientists at Bell Labs—John Bardeen, Walter Brattain, and William Shockley—created the first working transistor. This compact device could do the same job as a vacuum tube. But it was much smaller, used less power, and was more reliable.

By the 1950s, transistors were used in radios and early computers, making these devices smaller and easier to carry around. In 1956, MIT created the first computer that used transistors instead of vacuum tubes, showing just how useful they were for building faster, more efficient machines. By the 1960s, scientists figured out how to put many transistors onto a single chip. This lead to the creation of increasingly more powerful computer chips.

Learn more about the history of the microchip

Why are transistors so important?

Transistors are the core components in integrated circuits and chips. Today’s microchips can contain billions of transistors, allowing devices to perform complex tasks at high speeds while using less power. Their invention and continuous miniaturizations revolutionized electronics. They make it possible to build smaller, faster, and more efficient devices.

Today, transistors are everywhere—in smartphones, laptops, and virtually all electronic devices. They are the key to the digital world we live in, and keep getting smaller and more powerful as technology improves.

Learn more about the benefits and applications of integrated circuits