Sixty-five years ago yesterday, the Bell Labs team made up of William Shockley, John Bardeen, and Walter Brattain created what would soon be named the world's first transistor. It was a breakthrough invention?one that I would argue has been the most important innovation of the last 100 years.

Sixty-five years ago yesterday, the Bell Labs team made up of William Shockley, John Bardeen, and Walter Brattain created what would soon be named the world's first transistor. It was a breakthrough invention—one that I would argue has been the most important innovation of the last 100 years.

Above: John Bardeen, William Shockley, and Walter Brattain at Bell Labs, 1948

But while the transistor has been incredibly popular and versatile, my guess is that the team that worked on it had no inkling about most of its eventual applications. Indeed, the whole point of the solid-state physics group at Bell Labs, which was formed by Shockley in 1945, was to improve communications and essentially to replace the vacuum tubes and electromechanical switches then used in the phone system. Before the war, phone company researchers had used silicon to help detect vibrations, and afterward, Shockley started working on trying to develop semiconductors—such as silicon and germanium—to come up with a replacement for the vacuum tube. Two members of the group, theoretical physicist Bardeen and experimental physicist Brattain, conducted an experiment on December 16, 1947. They eventually figured out a method of using two gold contacts that were designed to connect to a point on a slab of germanium so the signal came in one contact and increased as it was sent out on the other, in what became known as a "point-contact transistor."



Above: A replica of the first working transistor

Later, Shockley would create a different approach, called the bipolar junction transistor, which proved much easier to manufacture. A few months later, Engineer John Pierce coined the term "transistor," a shortening of "transfer resistor." The transistor was announced on June 30, 1948, and it was a few years before it started to gain traction in the nascent electronics industry, notably in the transistor radio.

Over the years, the transistor made possible the portable radio, much smaller TVs, and, of course, computers as we know them. (The first very large computers had rows and rows of vacuum tubes, but transistors have proven much more reliable and much more compact.) Indeed, personal computers, portable phones, flat-panel televisions, personal media players, smartphones and tablets, networking, and the Internet wouldn't be possible without transistors. It's hard to think of anything that's changed our lives more in the past 50 years.

Perhaps the most amazing thing about transistors is how the industry has been able to shrink them in size, doubling the density roughly every two years in what is known as Moore's Law, after a paper by Intel co-founder Gordon Moore from 1965. The first transistor was about half an inch tall. For comparison, Intel's Ivy Bridge processor, which is about the size of your thumb nail, contains 1.4 billion transistors. That's pretty amazing.