The first transistor

[The first transistor] The first transistor A plastic wedge secured two gold contacts to the first transistor’s germanium surface. Voltage applied to one contact modulated the current flowing through the other, amplifying the input signal up to 100 times.

By Scott Hamilton

On December 23, 1947, a group of three inventors at Bell Laboratories got an early Christmas present. It was on this date that they demonstrated the world’s first working transistor. William Shockley, John Bardeen and Walter Brattain created the transistor, which was designed to replace the vacuum-tube triode, which performed the same function but used heat to control the flow of electrons across the junction. The concept behind the transistor, and the original vacuum-tube it eventually replaced, was to control electrical current from a higher voltage source using a lower voltage input. They were primarily used in amplifiers to allow signals to travel longer distances.

Bell Laboratories was the research arm of American Telephone and Telegraph (AT&T) and as such was primarily focused on improving telephone communication networks. The really crazy thing about this first transistor was that none of the three inventors really understood why it worked and the theory behind the invention was not fully understood until the early 1950s. This first transistor was based off of the prior theoretical research of Julius Edgar Lilienfeld, who filed a patent on the idea on October 22, 1925, but his ideas were widely ignored by industry.

It was not until later research in the 1990s that it was revealed that Shockley utilized a lot of information from Lilienfield’s patent in his work. Legal papers were released that showed evidence that Shockley and his team had built Lilienfeld’s transistor, but never referenced his work in their findings. This really means that Shockley’s success rode on Lilienfeld’s discovery from more than 22 years prior. For more information on Lilienfeld see

These first transistors consisted of two metal probes with a thin layer of germanium placed between their “points” and when a voltage was applied to the germanium, it allowed current to flow between the two metal points. This allowed a low voltage signal to control a high voltage signal, or amplify the signal. It was much smaller, used less power and produced less heat than the vacuum-tube technology.

These transistors brought about the birth of a new industry as researchers began to realize that they could operate not only as amplifiers, but also as switches. They eventually learned how they could be used to store the state of an electric charge. This led to the invention of the modern computer. This same transistor technology is still in use today, granted with a lot of improvements. These improvements are mainly in the manufacturing process of the materials used and the ability to make the surface area of the transistor much smaller. To put it into perspective, the first transistor was about the same size as the entire processor in your computer, which contains over 100 billion transistors. To learn more about the history of the transistor I recommend the excellent article at

Until next week, stay safe and learn something new.

Scott Hamilton is an Expert in Emerging Technologies at ATOS and can be reached with questions and comments via email to or through his website at

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