1st successful test of the transistor, December 16, 1947

What began as research to improve telephone service became one of the most important inventions in electronics history.

In 1945, AT&T’s research division, Bell Labs, began working on technology to replace vacuum tubes and make long-distance telephone service more reliable. William Shockley organized a solid-state physics group to research semiconductor replacements for vacuum tubes and electromechanical switches.

Possibly influenced by JE Lilienfled’s idea for the field-effect transistor patented in 1926, Shockley conceived of a “field-effect” amplifier and switch based on recent germanium and silicon technology. He built a small cylinder coated thinly with silicon, mounted close to a small, metal plate, but was unable to get it to work.

A member of the research team, John Bardeen, suggested electrons on the semiconductor surface could be blocking the penetration of electric fields in Shockley’s experiments. Bardeen and Walter Brattain began using a silicon contraption built to help study how electrons acted on the surface of a semiconductor to test the theory.

It wasn’t until December 16, 1947 that the first successful test of their semiconductor amplifier occurred. They applied two closely-spaced gold contacts held in place by a plastic wedge to the surface of a small slab of high-purity germanium. The voltage on one contact modulated the current flowing through the other, amplifying the input signal up to 100 times.

The team demonstrated the discovery a week later on December 23, often considered the date the transistor was invented.

For more detail: 1st successful test of the transistor, December 16, 1947


About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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