Transistor
Bardeen and Brattain demonstrate the point-contact transistor to Bell Labs officials
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Original prompt & settings (JSON) ↗A whisper of 'Hello' entered a microphone — and the loudspeaker at the other end answered with an amplified 'HELLO,' through a sliver of germanium under a gold-wrapped plastic triangle.
23 December 1947: the demonstration
At Bell Laboratories in Murray Hill, New Jersey, on 23 December 1947, John Bardeen and Walter Brattain demonstrated their point-contact transistor to laboratory officials. The device held two closely spaced gold-foil contacts against high-purity germanium with a plastic wedge.
For the audible proof, a microphone fed the input and a loudspeaker carried the output: speech entering the microphone emerged amplified; the December device was reported to amplify signals by up to 100 times. Shockley called what was presented to management a 'magnificent Christmas present.'
Three dates the listing blurs
The listing's date range blurs a sequence the record keeps separate: on 17 November Brattain was experimenting with silicon submerged in water, the successful two-contact germanium amplifier was obtained on 16 December, and the 23rd was its presentation to Bell Labs officials.
Bell Labs officials accepted the apparatus as a working solid-state amplifier. The demonstration established internally that the delicate germanium, gold and plastic assembly functioned as one.
Who was in the room
Bardeen explained the semiconductor surface states and devised the operating principle with Brattain, who built and tested the apparatus. William Shockley led the solid-state group and arranged the presentation, but played a smaller direct role in the point-contact device itself.
Acceptance allowed patent, naming and public-announcement work to proceed; Bell Labs announced the transistor at a press conference on 30 June 1948.
Sources
Researched 23 Aug 2026 5 sources 3 audit passes, 1 issue open Date corrected
How this was checked
Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →
Date corrected. The research places this at 1947-12-23.
What the sources leave uncertain
- November 17 was the beginning of the experimental sequence later called the “Miracle Month,” not the date of this demonstration.
- The first successful version was achieved on December 16; December 23 was the internal demonstration to laboratory officials.