The very first transistor — the foundational building block which almost all of modern civilization was built from — was created at AT&T’s Bell Labs on December 23 1947. As you can see above, this first transistor was huge and looked nothing like the millions of transistors that you’d find if you cracked open a modern computer chip (which are much too small to see with the naked eye, anyway). While the history of how we got from there to here is very interesting, today we’re going to look at something that’s normally glossed over: How those clever engineers at Bell Labs actually discovered the transistor in the first place.

The operation of a transistor is entirely based on a class of materials known as semiconductors, which chemists and engineers have known about since the mid-1800s. In 1833, Michael Faraday noted that silver sulfide decreased in electrical resistance when heated (metals usually increase in resistance when heated). In 1880, Alexander Graham Bell used selenium — a semiconductor that produces electricity when it’s struck by light — to transmit sound over a distance with his Photophone device.

Real analysis of semiconductors didn’t really begin until the 1920s, though, when scientists tried to work out why and how there was a class of materials that appeared to be metals, but behaved very differently than normal metals. With World War II, and the advent of radar and other radio technologies, semiconductors started to become very serious business. It wasn’t really until Bell Labs started researching semiconductors after WW2, though, that we finally started to learn about and control the properties of semiconductors.

In specific, Walter Brattain, John Bardeen, and William Shockley of Bell Labs decided to investigate the bulk and surface properties of silicon and germanium. Through a series of experiments, the researchers discovered that by applying a small amount of electricity to the surface of a piece of germanium, it could increase the flow of electricity through a second circuit that was also connected to the piece of germanium — in other words, an amplifier. The earliest germanium amplifiers used liquid electrolytes which would dry up, or were only capable of switching at low frequencies. Then, on December 23 1947, gold contacts were used instead of an electrolyte — and thus the first transistor was born. In the image at the top of the story, the piece of metal being “pointed” at by the triangle is the germanium. You can’t see the gold contacts from this angle, but you can see them in the video at around the 8:50 mark.

While Shockley wanted to call it a field-effect transistor, one Julius Edgar Lilienfeld had patented such a device way back in 1925, even though he apparently never built one. As a result, Bell Labs ended up patenting the first point-contact transistor and discovering the “transitor effect” — which, in 1956, would net Brattain, Bardeen, and Shockley the Nobel Prize in Physics.

By 1953, the first high-performance germanium transistors capable of switching at 60MHz were created; they were first used for transistor car radios, but they were also the first transistors suited to high-speed computing. The first silicon transistor wasn’t fabricated until 1954 (again by Bell Labs), and later that year Texas Instruments would go on to create the first commercial, mass-produced silicon transistor.

Finally, in 1960, Bell Labs produced the first metal-oxide-semiconductor field-effect transistor — the MOSFET. For the last 50 years, almost every transistor produced has been a MOSFET or some variation thereof. Bell Labs, we salute you. AT&T and your shady profit-gouging practices? Not so much. For what happened after 1960, check out our history of CPUs.