December 23, 1947, Bell Labs, New Jersey.
Three scientists gathered around a crude experimental apparatus. The device consisted of a piece of germanium crystal, two metal wires, and some plastic—looking completely unremarkable.
“Ready?” one asked.
Another nodded and switched on the power. The waveform on the oscilloscope changed—the input signal was amplified.
“It works!” the third person said excitedly.
This crude device was the world’s first transistor.
It was only a few centimeters tall, yet it replaced fist-sized vacuum tubes. It had no fragile glass shell, no hot filament, and an almost infinite lifespan.
It would change everything.
The Vacuum Tube Dilemma#
To understand why the transistor was important, first understand the problems with vacuum tubes.
Vacuum tubes were the core components of early electronic devices. Radios, televisions, early computers all relied on them.
But vacuum tubes had too many defects:
Large size: Each vacuum tube was like a small light bulb. ENIAC used 18,000 of them, filling an entire room.
High power consumption: Vacuum tubes needed to heat filaments to work, each consuming several watts. ENIAC consumed 150 kilowatts, mostly turned into heat.
Short lifespan: Filaments burned out, glass broke, vacuum leaked. ENIAC averaged one vacuum tube failure every two days; engineers were replacing parts every day.
Slow speed: Vacuum tubes needed warm-up time, switching speed was limited, restricting computer calculation speed.
By the 1940s, electronic device development was “stuck” on vacuum tubes. Engineers desperately needed a better component.
Bell Labs’ Exploration#
Bell Labs was AT&T’s research institution, one of the world’s top laboratories at the time.
Lab leadership realized: The telephone system needed better amplifiers. Long-distance telephone signals attenuated and needed amplifiers to boost them. The amplifiers of the time used vacuum tubes—large, power-hungry, unreliable.
In 1939, research director Mervin Kelly wrote: “The telephone system needs an amplifier that doesn’t use vacuum tubes. I believe the answer lies in semiconductors.”
What is a semiconductor?
Conductors (like copper) conduct electricity easily; insulators (like glass) barely conduct at all. Semiconductors have conductivity between the two, and their conductivity can be changed by doping with impurities.
More importantly, semiconductor conductivity can be controlled—apply voltage, it conducts; remove voltage, it insulates. This is exactly what switches and amplifiers need.
The Three Scientists#
In 1945, Bell Labs formed a team to research semiconductor amplifiers. The team had three core members:
William Shockley: Theoretical physicist, team leader. He proposed the field-effect transistor theory, but early experiments failed.
John Bardeen: Theoretical physicist, later Nobel Prize winner. He proposed surface state theory, explaining why Shockley’s experiments failed.
Walter Brattain: Experimental physicist, extremely hands-on. He designed various experimental apparatuses to verify theoretical predictions.
The three had very different personalities: Shockley was ambitious and competitive; Bardeen was quiet and thoughtful; Brattain was enthusiastic and straightforward.
They had both cooperation and friction. But it was precisely this collision that gave birth to a great invention.
Inventing the Transistor#
In November 1947, Bardeen and Brattain had a breakthrough idea.
They discovered that if two very close metal contacts were placed on the surface of a germanium crystal, the current at one contact could control the current at the other—this was amplification!
On December 16, they used gold foil and a plastic wedge to make the first point-contact transistor. On December 23, they demonstrated the device to Bell Labs leadership.
How a transistor works:
A transistor has three terminals: emitter, base, and collector. A small current at the base can control a large current between emitter and collector—like a faucet controlling water flow.
This property allows transistors to:
- Amplify signals: Small signals become large signals
- Act as switches: Conduct when current present, cut off when absent
This is exactly what vacuum tubes could do, but transistors were smaller, more power-efficient, and more reliable.
Shockley’s Anger#
When Bardeen and Brattain invented the transistor, Shockley wasn’t present. When he learned the news, he was both happy and angry.
Happy that the team succeeded. Angry that he wasn’t the inventor—only Bardeen and Brattain’s names were on the patent.
For the next month, Shockley locked himself in his office and designed a better transistor: the junction transistor.
The junction transistor didn’t need precision metal contacts, had a simpler structure, and was easier to manufacture. It became the mainstream transistor structure later.
In 1951, Bell Labs announced the junction transistor invention. This time, Shockley was the sole inventor.
Transistor Computers#
After the transistor was invented, it was quickly applied to computers.
In 1954, Bell Labs built TRADIC—the first transistor computer. It had only 800 transistors but already matched ENIAC’s performance, while being one-thousandth the size.
In 1955, IBM introduced the IBM 608—the first commercial transistor computer. It had 3,000 transistors and was one-tenth the size of the last vacuum tube computer, the IBM 604.
Advantages of transistor computers:
| Feature | Vacuum Tube Computer | Transistor Computer |
|---|---|---|
| Size | Room-sized | Cabinet-sized |
| Power consumption | Tens of kilowatts | Several kilowatts |
| Reliability | Daily failures | Monthly failures |
| Speed | Millisecond level | Microsecond level |
Transistor computers were called “second-generation computers,” marking computers moving from laboratories to commercial applications.
The Nobel Prize#
In 1956, Shockley, Bardeen, and Brattain jointly received the Nobel Prize in Physics.
This was one of the fastest Nobel Prize awards in history—from invention to award took only 8 years. Usually, Nobel Prizes wait decades to confirm the importance of a discovery.
But the transistor’s importance was too obvious. The Nobel Committee said: “This invention may have changed human daily life more profoundly than any other invention.”
Shockley Semiconductor#
After winning the prize, Shockley made a decision: start a company.
In 1956, he returned to his hometown in California and founded Shockley Semiconductor Laboratory. He recruited the best talent from Bell Labs.
But Shockley was a terrible manager. He was autocratic, suspicious, and difficult to work with. Within two years, eight core employees resigned together and founded Fairchild Semiconductor.
These eight people were called the “Traitorous Eight.” They later founded Intel, AMD, and other companies, launching the Silicon Valley legend.
Shockley Semiconductor ultimately failed. But Shockley inadvertently ignited the spark of Silicon Valley—the talent he attracted and the technical foundation he established became the starting point for Silicon Valley’s rise.
From Transistors to Integrated Circuits#
Transistors were much better than vacuum tubes, but still not enough.
A computer needed thousands of transistors, each manufactured separately, packaged separately, connected separately. The transistor itself was small, but packaging and wiring took up most of the space.
Engineers began thinking: Could multiple transistors be made on the same piece of material?
This idea would lead to the birth of integrated circuits.
Tomorrow, we’ll discuss the miracle of chips—how to integrate entire circuits onto small silicon wafers.
Today’s Key Concepts#
Transistor A semiconductor device that can amplify signals or act as an electronic switch. Has three terminals: emitter, base, collector. A small current at the base can control a large current between emitter and collector. Transistors replaced vacuum tubes and became the foundational component of modern electronic devices.
Semiconductor Material with conductivity between conductors and insulators, such as silicon and germanium. By doping with impurities (like phosphorus and boron), semiconductor conductivity characteristics can be changed to manufacture various electronic devices. Silicon is the most commonly used semiconductor material.
Junction Transistor A transistor structure invented by Shockley, consisting of two PN junctions. Simpler, more reliable, and easier to manufacture than the point-contact transistor invented by Bardeen and Brattain, it became the mainstream transistor type.
Discussion Questions#
- Transistors are much smaller, more power-efficient, and more reliable than vacuum tubes. Which of these three advantages do you think was most important for computer development?
- Shockley was a genius scientist but a terrible manager. Do you think scientific genius and management ability are related?
Tomorrow’s Preview: The Miracle of Integrated Circuits—how to pack thousands of transistors onto a tiny silicon chip?