# [TECH] Transistor
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**The Transistor** (1947, Bell Labs) is a semiconductor device that amplifies or switches electrical signals, replacing vacuum tubes and enabling the entire semiconductor industry.
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## Overview
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John Bardeen, Walter Brattain, and William Shockley demonstrated the point-contact transistor at Bell Labs (December 23, 1947). Shockley's bipolar junction transistor (1948) and the MOS field-effect transistor (MOSFET, Kahng & Atalla, 1960) followed. The MOSFET became the workhorse of integrated circuits — by 2023 approximately 10²² MOSFETs had been manufactured, more than any other human-made object. The transistor replaced vacuum tubes in radios and computers by 1960, enabling miniaturisation and reliability improvements of many orders of magnitude.
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## Key Actors
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- **Companies**: Bell Labs/AT&T (invention), Texas Instruments (first silicon transistor, 1954), Fairchild Semiconductor (1957), Intel (1968)
- **Inventors**: Bardeen, Brattain, Shockley (Nobel 1956); Dawon Kahng & Martin Atalla (MOSFET, 1959)
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## Key Patents
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- Shockley, W. US Patent 2,569,347 (1951) — junction transistor
- Kahng, D. & Atalla, M. US Patent 3,102,230 (1963) — MOSFET
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## Economic Value
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Global semiconductor market: **$600 billion/year** (2023, WSTS). Electronics and computing enabled by transistors: $5–8T/year. The transistor is possibly the most economically valuable invention of the 20th century.
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## Notes
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WSTS *Semiconductor Market Forecast* 2023. Some economists estimate the transistor's cumulative economic value at $100T+ since 1950 when accounting for all electronics, communications, and computing it enabled.
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# Parents
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* [SCI] Semiconductor Physics⏎