The Invention of the Transistor
Bell Labs' 1950 patent for the point-contact transistor, the fundamental electronic component that makes all modern computing possible.
Original patent title: “Three-electrode circuit element utilizing semiconductive materials”
Bell Labs' 1950 patent for the point-contact transistor, the fundamental electronic component that makes all modern computing possible. Granted to Bell Telephone Laboratories Inc in 1950 with 130 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This patent describes the first working transistor, a three-electrode circuit element that controls the flow of electricity through a semiconductive material. By applying a small voltage to a control electrode, the device can amplify or switch a much larger current flowing between two other electrodes. This mechanism replaced bulky, fragile, and power-hungry vacuum tubes with a tiny, solid-state component. It effectively functions as an electronic gate, allowing binary data to be processed at high speeds.
The gap
What does this patent NOT cover?
- Does not cover junction transistors, which were developed later and use different internal structures.
- Does not cover integrated circuits, which combine many transistors onto a single chip.
- Does not cover field-effect transistors (FETs) that use an insulated gate structure.
- Does not cover modern silicon-based manufacturing processes like photolithography.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The invention realized that current flow in a semiconductor could be modulated by placing two closely spaced contacts on a crystal surface, creating a solid-state amplifier without needing a heated filament.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Early transistor radios
Bell Labs' original point-contact transistor prototypes
Foundational hardware for early digital computers
Why it matters
The bigger picture
This is the foundational patent of the information age. It triggered the transition from analog vacuum tube technology to digital solid-state electronics, enabling the creation of everything from portable radios to the supercomputers and smartphones we use today.
Filed
June 17, 1948
Granted
October 3, 1950
Market context
Who's building on this
Companies in this space
Every major semiconductor company, including Intel, TSMC, and Samsung, builds upon the fundamental physics described here. While the specific point-contact design is obsolete, the principle of solid-state switching remains the industry standard.
Market impact
This patent effectively launched the multi-trillion dollar semiconductor industry. It rendered vacuum tube manufacturers obsolete and created the technical foundation for the entire digital economy.
Claim 1 — Plain English
What this patent covers
This patent describes the first working transistor, a three-electrode circuit element that controls the flow of electricity through a semiconductive material. By applying a small voltage to a control electrode, the device can amplify or switch a much larger current flowing between two other electrodes. This mechanism replaced bulky, fragile, and power-hungry vacuum tubes with a tiny, solid-state component. It effectively functions as an electronic gate, allowing binary data to be processed at high speeds.
The clever bit
The invention realized that current flow in a semiconductor could be modulated by placing two closely spaced contacts on a crystal surface, creating a solid-state amplifier without needing a heated filament.
What it does not cover
- Does not cover junction transistors, which were developed later and use different internal structures.
- Does not cover integrated circuits, which combine many transistors onto a single chip.
- Does not cover field-effect transistors (FETs) that use an insulated gate structure.
- Does not cover modern silicon-based manufacturing processes like photolithography.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Moderate
Citation count
40/40
Highly cited
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$50K – $161K
Midpoint $101K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Claim text not yet imported for this patent
Concepts involved
Citations
Patent lineage
Cite this patent
Brattain, W. H., & John, B. (1950). The Invention of the Transistor (U.S. Patent No. 2,524,035). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2524035/point-contact-transistor
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does The Invention of the Transistor cover?
Bell Labs' 1950 patent for the point-contact transistor, the fundamental electronic component that makes all modern computing possible.
Who owns patent US 2524035?
Bell Telephone Laboratories Inc owns this patent, granted in 1950.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 2524035 cited by?
This patent has been cited by 130 later patents that build on its ideas.
What problem does this patent solve?
This is the foundational patent of the information age. It triggered the transition from analog vacuum tube technology to digital solid-state electronics, enabling the creation of everything from portable radios to the supercomputers and smartphones we use today.
What does this patent NOT cover?
Does not cover junction transistors, which were developed later and use different internal structures.
Same assignee
More from Bell Telephone Laboratories Inc
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