The History and Engineering of the World’s Most Important Thing: The Transistor

In a world filled with things, you might think that settling on what the most important thing of all would be rather difficult. That, however, isn’t the case.

Modern innovation is solely dependent on the transistor and it’s invention and continual improvement thanks to Moore’s law. For those of us unfamiliar with this modern engineering marvel, it is a three-terminal solid-state electronic device. In essence, it allows us to control the current or voltage between two of the terminals by applying an electric current or voltage to the third terminal. For non-engineers, this functionality may seem befuddlingly simple to be the root of all modern innovation, but yet, that is the case – for many fascinating reasons.

Amplifiers, computers, cell phones, nearly everything electronic relies on this three terminal electrical invention. The three-terminal aspect of the transistor allows it to amplify electrical signals, like in radios. It can also be used for electric switches that can be controlled by other switches, made out of, you guessed it, transistors. The importance of this “thing” truly can’t be underscored enough.

Modern technology rapidly advances surrounding the transistor industry. Now, we can pack 1 million transistors on a single centimeter of a silicon chip capable of switch rates of 1 nanosecond. This wasn’t always the case.

The Humble Beginnings of the Transistor

While transistors are now essentially the only efficient way to construct three-terminal devices, the first three-terminal devices were known as vacuum tubes. These tubes were the foundation of old radios and televisions and they are first examples of transistor technology.

Thomas Edison’s light bulb was a vacuum tube. Having a vacuum inside of a sealed glass capsule allows for unique electrical properties to be harnessed. Edison’s lightbulb, while not the first use of vacuum tubes, was one of the more prominent early applications.

Light bulbs even to this day function essentially as diodes or electrical components with only 2 terminals. Soon after the initial invention of vacuum tube light bulbs, a third terminal was added into the tube to investigate what would happen. This was initially done with the sole intent of investigating cathode rays, electrical phenomena that were observed around the filament of light bulbs.

Joseph John Thomson pioneered research in cathode rays and was also the original inventor of the vacuum tube, designed for cathode ray investigation. He demonstrated that these rays were made up of particles contained in all material – he discovered electrons. For this, he won the Nobel Prize in physics in 1906.

These discoveries cemented the groundwork for transistor creation.

While Thomson was undergoing his groundbreaking research, physicists were also trying to figure out how to control cathode rays (electrons) and apply them to electronic devices. Lee De Forest was the first inventor of a triode enclosed in a vacuum tube in 1906, this device functioning similar to transistors.

This triode device allowed him to amplify audio signals which made AM radio possible. This invention essentially revolutionized how media was spread across the globe. In many ways, Forest and his invention began the information age.

The triode invented by Forest underwent a number of improvements and changes until it eventually pushed forward the development of computational devices. Electronic vacuum tubes were used in many different computer designs in the 1940s and 50s, but these tubes were bulky and inefficient. Their limitations soon heavily controlled their application.

In response to the limitations of vacuum tubes, engineers tied packing multiple triodes within one vacuum tube to use up space much more efficiently. This worked for some time until yet again, more computing power was needed. This drive to make triodes and eventually transistors smaller and more efficient laid the foundation for one of the most important governing principles to technological advancement in the modern era: Moore’s Law.

Early Computers and Their Vacuum Problem

In the 1940s when large computers were just starting to be developed, the largest required over 10,000 vacuum tubes and took up 93 square meters of space. These computers were massive – clearly, a new solution was needed.

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Since vacuum tubes were so problem-prone, engineers and scientists sought new ways to create triode devices. Instead of using electrons in vacuums, they started to experiment with controlling electrons in solid materials, like semiconductors. These experiments created the first transistor.

Stepping back from the 1940s, engineers knew how to create diodes with solid materials as early as the 1920s. however, it wasn’t until 20 years later that researchers determined a way to add a third terminal to semiconductor devices. After this initial invention, technology innovation grew rapidly.

Transistors and Moore’s Law

1947 was the year that John Bardeen and Walter Brattain were able to create the first transistor while working as engineers at Bell Telephone Laboratories. They discovered that if they made two point contacts close to one another in a semiconductor material, they could easily add a third terminal and create a “point contact” transistor, the first of its kind.

After initial discovery, Bardeen and Brattain created many of the same transistors and connected them to other components to make an audio amplifier. The amplifier was shown to the executives at Bell Telephone Company, who were blown away by the fact that the transistors didn’t need to “warm up” like vacuum tubes needed to. It was at this point that the groundbreaking innovation of the transistor was realized.

This first discovery and successful manufacturing of a solid-state transistor sparked a massive research effort into solid state electronics. Bardeen and Brattain won the Nobel Prize in Physics in 1956, along with William Shockley, another scientist researching transistors.

The advancement of transistor capability is encapsulated in a famous principle, Moore’s Law. It refers to the observation made by Gordon Moore, a founder of Intel, in 1965. He noticed that the number of transistors per square inch on an integrated circuit doubled every year since their invention. He predicted that the trend would continue into the foreseeable future, which it did.

While Moore may not have made this observation until 1965, the early beginnings of it can be seen in the rapid innovations made in solid-state electronics since their creation.

Early Transistor Limitations

While transistors form the basis of modern innovation, there were initial problems surrounded how they were used. In the early years, transistors were made as individual components connected to other electronic components such as resistors and capacitors to make completed circuits. Problems eventually arose, however, as more and more transistors were demanded to be packed into smaller and smaller spaces.

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These initial problems were soon overcome as transistors were developed as integrated circuits. These integrated circuits allowed for the manufacturing of many transistors into a single component that could then be hooked up into another circuit.

The Final Solution: Integrated Circuits

Developed in 1959, Jack Kilby, an engineer at Texas Instruments and Robert Noyce, an engineer at Fairchild Camera, their invention of integrated circuits would go on to shape the world. Rather than making transistors one by one, they were able to make several transistors at the same time on the same semiconductor. Their discovery also allowed for the inclusion of other components like resistors, capacitors, and diodes all incorporated into the same piece of semiconductor.

After this final invention of the integrated circuitry, the rest is history.

Transistors continued to grow smaller and smaller, and their capabilities only exponentially increased. Nearly everything around us we can owe thanks to transistors, whether indirectly or directly. While the more obvious electronics can owe their capabilities to underlying transistor technology, we can even thank transistors for other things like our furniture and homes. Transistors indirectly allow these other goods and services to be rendered at a fraction of previous prices and gave way to computer numerically controlled manufacturing, among a multitude of other processes.

Transistors are unequivocally the most important things in the world.

Trevor is a civil engineer by trade and an accomplished internet blogger with a passion for inspiring everyone with new and exciting technologies. He is also a published children’s book author whose most recent book, ZOOM Go the Vehicles, is aimed at inspiring young kids to have an interest in engineering.


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