Summary of 1st successful test of the transistor, December 16, 1947
This article details the 1945 Bell Labs research project that led to the invention of the transistor. The team aimed to replace vacuum tubes with semiconductor technology to improve telephone service reliability. Key figures included William Shockley, John Bardeen, and Walter Brattain. After initial failures with silicon, they successfully tested a germanium-based amplifier on December 16, 1947, demonstrating it a week later.
Parts used in the Transistor Invention Project:
- Vacuum tubes
- Semiconductor replacements
- Electromechanical switches
- Germanium technology
- Silicon technology
- Silicon cylinder
- Metal plate
- High-purity germanium slab
- Gold contacts
- Plastic wedge
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
- What was the original goal of the Bell Labs research in 1945?
The goal was to replace vacuum tubes and make long-distance telephone service more reliable. - Who organized the solid-state physics group at Bell Labs?
William Shockley organized the group to research semiconductor replacements. - Why did Shockley's initial silicon experiment fail?
John Bardeen suggested electrons on the semiconductor surface were blocking the penetration of electric fields. - When did the first successful test of the semiconductor amplifier occur?
The first successful test occurred on December 16, 1947. - What materials were used to create the first working device?
The device used a small slab of high-purity germanium, two closely-spaced gold contacts, and a plastic wedge. - How much did the first amplifier increase the input signal?
The amplifier could amplify the input signal up to 100 times. - Which date is often considered the official invention date of the transistor?
December 23 is often considered the date the transistor was invented. - Did JE Lilienfeld influence the conception of the field-effect amplifier?
Yes, the team was possibly influenced by JE Lilienfeld's idea for the field-effect transistor patented in 1926.
