진공관의 탄생 (2): 드 포레스트와 삼극관(Audion)의 탄생 - The History of Vacuum Tubes (2): De Forest, Audion, and the First Triode
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| 작은 관이 오디온 |
■ 1904년, 플레밍의 성공
신호를 검출하기는 했지만 여전히 한계가 있었는데 검출된 신호의 크기는 만족스럽지 않았습니다. 당시 기술자들은 더 나은 검파기를 원했고 신호 손실을 최소화 하도록 진공관의 검파 효율을 높히고자 했습니다. 그리고 이 문제를 해결하려 한 사람이 드 포레스트였습니다.
■ 예일대학교의 젊은 발명가
■ 드포레스트는 전자를 연구한 것이 아니있다
■ 최초의 그리드는 진공관 밖에 있었다
US841386A - Wireless telegraphy. - Google Patents
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| US Patent 841,386 |
현대인의 눈에는 코일처럼 보입니다. 하지만 사실상 자기장 장치라기보다는 전기장 결합 장치에 가까웠습니다. 그는 안테나 신호를 여기에 연결해 관 내부의 전도 상태에 영향을 주려고 했던 것입니다.
■ 역사상 가장 중요한 생각
■ 플레밍과 드 포레스트는 무엇이 달랐을까
■ 놀랍게도 그는 증폭을 몰랐다
■ 1912년, 무대는 GE 연구소로 옮겨진다
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Irving Langmuir |
1909년 그는 GE 연구소에 입사합니다. GE는 사실 에디슨의 회사였다 여기서 놀라운 연결고리가 나타납니다. GE(General Electric)는 1892년 Edison General Electric 과 Thomson-Houston 의 합병으로 탄생한 회사입니다. 즉 그 뿌리는 에디슨에게 있습니다. 갑자기 소름이 돋는 연결이 보입니다.
■ 랭뮤어가 발견한 진실
■ 랭뮤어의 진공관들
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| UX-112A |
오늘날 오디오 애호가들은 잘 모르지만, 실제로는 이 관들이 현대 증폭관의 진정한 조상입니다. 당시 RCA가 판매했지만 기술은 GE 연구소와 웨스팅하우스의 연구결과가 녹아 있었습니다. 지금으로 말하면
■ 사실 45 의 아버지는 누구일까
■ 과학은 왜 이렇게 발전할까
■ 맺으며
The Birth of the Vacuum Tube (Part 2)
Lee De Forest and the Triode — The Moment Modern Electronics Was Born
"A discovery may be made by one person, but civilization is built by many."
In the previous article, we explored the events that led to the birth of the vacuum tube.
In 1883, Thomas Edison noticed a curious phenomenon while developing the incandescent lamp. Something invisible seemed to leave the hot filament and travel across the vacuum to a nearby metal plate. Today, we call this the Edison Effect.
Edison observed it—but he didn't know what it was.
In 1897, J. J. Thomson revealed that those mysterious particles were electrons.
In 1904, John Ambrose Fleming transformed the Edison Effect into the world's first practical vacuum tube—the Fleming Valve, or diode.
Then, only two years later, humanity took an even greater step.
We moved beyond merely discovering electrons.
We learned to control them.
At the center of that story stood one remarkable inventor:
Lee De Forest (1873–1961).
Fleming's Success—And Its Limitation
When Fleming introduced his diode in November 1904, wireless communication was entering a golden age.
Only three years earlier, Guglielmo Marconi had demonstrated transatlantic wireless communication, inspiring the world with the possibility of sending messages without wires.
But engineers faced a serious problem.
Receiving weak radio signals was far more difficult than transmitting them.
Fleming's diode solved part of the problem.
Its construction was beautifully simple:
A heated cathode
A positively charged plate
It worked as a reliable detector.
But it still had one important weakness.
The detected signal remained extremely small.
Engineers wanted greater sensitivity and better detection efficiency.
Among those searching for a solution was Lee De Forest.
A Young Inventor from Yale
Lee De Forest was born in 1873 in Council Bluffs, Iowa, and earned his Ph.D. from Yale University in 1899.
Unlike theoretical physicists such as J. J. Thomson or the future Irving Langmuir, De Forest was an inventor at heart.
In many ways, he resembled Edison.
When confronted with an unusual phenomenon, his first instinct wasn't:
"Why does this happen?"
Instead, he asked:
"What happens if I try this?"
He loved experimentation.
That curiosity would change the world.
He Wasn't Really Studying Electrons
Today, whenever we think about vacuum tubes, we naturally think about electrons.
But in 1905, De Forest did not.
The electron had been discovered only eight years earlier.
Scientists were still trying to understand electrical conduction inside partially evacuated tubes.
Many believed that residual gas played an essential role.
Researchers studied:
Electrical discharge
Gas conductivity
Electric sparks
The influence of radio waves
De Forest became fascinated by one particular question:
"Could an external electrical signal somehow influence the conductivity inside the tube?"
Today, the idea sounds primitive.
At the time, it was entirely reasonable.
The First Grid Was Outside the Tube
Around 1905, De Forest began experimenting with Fleming's diode.
One of his earliest ideas was surprisingly simple.
He wrapped a wire around the outside of the glass envelope.
To modern eyes, it resembles a coil.
But its purpose was not to create a magnetic field.
Instead, it attempted to influence the electrical conditions inside the tube through electric-field coupling.
He connected the antenna signal to this external wire, hoping to alter the tube's conductivity.
The effect was small.
But it sparked an even bigger idea.
One Tiny Wire Changed Everything
If an external wire could influence the tube...
Wouldn't an internal wire work even better?
So De Forest placed a fine wire inside the vacuum tube.
In October 1906, that tiny decision changed the history of electronics.
The new structure contained three electrodes:
Plate (Anode)
Grid
Cathode
He called it the Audion.
Today, we know it simply as the Triode.
Every electronic amplifier in history can trace its ancestry back to that moment.
Fleming and De Forest Thought Differently
Fleming's diode detected radio signals by allowing current to flow in only one direction.
De Forest approached the problem differently.
Instead of applying the incoming radio signal to the plate circuit, he applied it to the newly added grid.
That distinction changed everything.
For the first time, the incoming signal was applied to a control electrode rather than to the main current path.
To us, this seems obvious.
In 1906, it was revolutionary.
Ironically, De Forest was not trying to build an amplifier.
He believed the grid was influencing the conductivity of the gas remaining inside the tube.
He did not yet understand the true mechanism.
He Didn't Know He Had Invented Amplification
History becomes especially fascinating here.
Today we know that a tiny change in grid voltage produces a much larger change in plate current.
That is the very definition of amplification.
But De Forest never fully understood what he had discovered.
He believed he had simply created an extraordinarily sensitive radio detector.
His early Audion tubes contained considerable residual gas and behaved unpredictably.
Compared with later tubes such as the 45, 2A3, or 300B, they almost belonged to a different species.
Yet hidden inside those imperfect devices was one of the greatest inventions in history.
Then the Story Moved to General Electric
Another remarkable figure now enters the story.
Irving Langmuir.
Born in Brooklyn in 1881, Langmuir studied at Columbia University before earning his doctorate at the University of Göttingen in Germany.
In 1909, he joined the research laboratories of General Electric.
This connection is more significant than it first appears.
General Electric had been formed in 1892 through the merger of Edison General Electric and Thomson-Houston.
In other words, the company itself traced its roots back to Edison.
Suddenly, the historical timeline takes on a remarkable symmetry.
1883 — Edison discovers the Edison Effect.
1904 — Fleming invents the diode.
1906 — De Forest invents the Audion.
1909 — Langmuir begins refining the triode at GE.
1929 — The Type 45 appears.
1932 — The 2A3 is introduced.
1938 — The legendary 300B is born.
One could almost say that the history of the vacuum tube began with Edison—and reached maturity at the company that carried his name.
Langmuir Discovered the Truth
While studying the Audion, Langmuir reached a conclusion completely opposite to De Forest's.
De Forest believed that residual gas helped the tube operate.
Langmuir discovered the opposite.
Residual gas was the problem.
It scattered electrons, caused instability, and made every tube behave differently.
His solution was simple in concept but revolutionary in practice:
Remove as much gas as possible.
The result was the high-vacuum triode.
For the first time, engineers could clearly understand the space charge surrounding the cathode.
Vacuum tubes became predictable.
They became scientific devices rather than mysterious ones.
Design replaced trial and error.
Modern electronics had truly arrived.
The Tubes That Changed Everything
Interestingly, there is no famous audio tube bearing Langmuir's name.
Yet his research made nearly every famous tube possible.
Early examples included:
UV-201
UV-201A
UX-112A
UX-171A
Today, many audio enthusiasts overlook these early tubes.
In reality, they are the true ancestors of nearly every classic power triode.
Although RCA sold many of them commercially, much of the underlying research came from General Electric and Westinghouse.
In modern terms, we might say:
GE performed the research.
RCA brought it to market.
Who Was the Real Father of the Type 45?
Many people imagine a simple historical line:
Fleming → De Forest → Type 45.
But history was more complicated.
The true progression looks more like this:
Fleming
↓
De Forest (the invention of the triode)
↓
Langmuir (scientific understanding)
↓
UV-201A
↓
UX-171A
↓
Type 45
Perhaps the beloved 45, 2A3, and 300B are not simply De Forest's descendants.
Perhaps they are Langmuir's grandchildren.
How Science Really Advances
Looking back, a pattern emerges.
Edison discovered a phenomenon.
He didn't understand it.
But he preserved it.
De Forest discovered amplification.
He didn't understand it either.
But he kept experimenting.
Then Langmuir arrived.
He explained why it worked.
That explanation led to even greater inventions.
Science has always progressed like a relay race.
One person opens the door.
Another explains the path.
A third travels farther than either of them imagined.
Conclusion
Sometimes, when studying history, it almost feels as though an invisible design has been quietly guiding events.
In 1883, Edison could never have imagined that the strange effect inside one of his light bulbs would eventually lead to the 300B.
In 1906, De Forest had no idea that his Audion would become the foundation of the entire electronics industry.
In 1909, Langmuir could not have known that his research would one day live on inside the 45, the 2A3, and the 300B—tubes cherished by audiophiles around the world.
Yet history unfolded exactly that way.
One person discovered.
Another explained.
Another refined.
Together, they created an entirely new civilization.
In the end, the history of the vacuum tube is not simply the story of electrons.
It is the story of people.
It began with Edison.
It reached its turning point with De Forest.
And it achieved scientific maturity through Langmuir.
The glowing glass tubes we admire today are more than beautiful pieces of engineering.
They are reminders that every great technological revolution is built not by a single genius, but by generations of curious minds working together.
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