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The first working transistor, built at Bell Labs in December 1947, was made from which semiconductor?

Germanium, as a point-contact transistor.

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  1. Silicon
  2. Gallium arsenide
  3. Germanium ✔

Why: Bardeen and Brattain pressed two closely spaced gold contacts onto high-purity germanium. Their point-contact device amplified an input signal up to 100 times.

Huh, didn't know that: Bell Labs announced the transistor at a press conference in New York on June 30, 1948.

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Why was the first transistor so proud? It amplified everything Bell Labs said.
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References

Answer: Germanium. Bardeen and Brattain pressed two closely spaced gold contacts onto high-purity germanium. Their point-contact device amplified an input signal up to 100 times.

  1. Computer History Museum, 1947: Invention of the Point-Contact Transistor www.computerhistory.org/siliconengine/invention-of-the-point-contact-transistor
    John Bardeen & Walter Brattain achieve transistor action in a germanium point-contact device in December 1947.
    Checked 2026-10-10.

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