Seventy-five years ago, on a Tuesday morning, December 16, 1947, two physicists at Bell Telephone Laboratories, put current into gold electrodes on a half-inch slab of germanium and were able to get out an amplified electrical signal. It sounds pretty technical—and it was. The result was the first transistor, and it has utterly transformed our modern world.
As with most technologies, the story of the transistor involves a lot of players, but the three most important were John Bardeen, William Shockley, and Walter Brattain.
![John Bardeen, William Shockley, and Walter Brattain at Bell Labs, 1948](https://i.pcmag.com/imagery/articles/05pet9jZSCfEa6lvgPhIE1o-2.jpg)
During the Second World War, AT&T's Bell Labs started work on solid-state physics, as a way of creating more reliable communications. William Shockley was picked to head up these efforts, and by April 1945 he had created the idea to use external electric fields to influence the behavior of electrons and holes inside narrow layers of semiconductors. He started experimenting with a variety of options and materials for these "field effect" transistors but couldn’t create a working device.
A few months later, he took over a group of researchers to work with semiconductor materials in Bell Labs' Solid State Physics lab.
One of these researchers was theoretical physicist John Bardeen, and he and others, including experimental physicist Walter Brattain, started working with different materials, looking for larger effects. They made big steps forward throughout 1946 and 1947, and by November of ‘47, Bardeen and Brattain were working with gold electrical contacts on sheets of germanium.
This was right in theory, but it didn't work properly until Brattain figured out how to use a polystyrene wedge to create a small gap (about 2 mils) between two contacts. On December 16, he hooked it up to his battery, and with Bardeen looking on, he immediately saw a 30% power gain. With a little tuning, he found he could boost the power gain to 450%, proof that their device, now called a point-contact transistor, worked.
![Replica of the first transistor](https://i.pcmag.com/imagery/articles/05pet9jZSCfEa6lvgPhIE1o-3.jpg)
They showed their demonstration to many people inside Bell Labs, and there was a lot of excitement. But it was a difficult device, not well understood, and was still a long way away from being able to replace the vacuum tubes that has previously been used in electronic circuits.
The following month, Shockley came up with a different way of creating a transistor, creating the bipolar junction transistor, which was to become the basic idea behind most of the successful semiconductor devices for decades to come.
Bell Labs made the public announcement of the transistor on June 30, 1948. Still, it took years for transistors to become widely used, but once they did, they utterly transformed our world, leading to computer memory, integrated circuits, microprocessors, and many other products. Perhaps the biggest change was the development of the metal-oxide semiconductor field effect transistor or MOSFET, which powered the industry for years.
For their efforts in creating the transistor, Bardeen, Brattain, and Shockley won the Nobel Prize in Physics in 1956. Bardeen later moved to the University of Illinois, where his work on superconductivity won him a second Nobel Prize. Shockley moved to Palo Alto in 1956 and started Shockley Semiconductor; later the key employees of that firm left to create Fairchild Semiconductor (where Robert Noyce and Jean Hoerni created the key ideas behind the integrated circuit) and later Intel.
One of the most notable aspects of transistors is how scientists and engineers have been able to continually make them smaller and smaller, so you can make devices that contain them more dense, a process usually referred to as Moore's Law. That first transistor was about half an inch long; today, a standard CPU for a phone or a PC has over a billion transistors.
I've said before that I believe the transistor was the most important invention of the 20th century, as it led to the ubiquity of all the electronic devices we have today, not to mention the applications that run on top of these. And it all started 75 years ago.