# The Invention of the Transistor

> Bell Labs' 1950 patent for the point-contact transistor, the fundamental electronic component that makes all modern computing possible.

- **Patent:** US 2524035
- **Original title:** Three-electrode circuit element utilizing semiconductive materials
- **Owner:** Bell Telephone Laboratories Inc
- **Granted:** 1950
- **Status:** Public domain (expired)
- **Times cited:** 130
- **Field:** semiconductors, telecommunications, consumer_electronics

## What it does

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.

## 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.

## 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.

## Real-world examples

1. Early transistor radios
2. Bell Labs' original point-contact transistor prototypes
3. Foundational hardware for early digital computers

## Why it matters

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.

## 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.

**Full plain-English explainer:** https://patentbrief.org/patent/us/2524035/point-contact-transistor

**Original patent:** https://patents.google.com/patent/US2524035

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [The Invention of the Junction Transistor](https://patentbrief.org/patent/us/2569347/junction-transistor) — William Shockley's 1951 patent for the junction transistor, the fundamental building block of all modern digital electronics.
- [The Invention of the Modern Field-Effect Transistor](https://patentbrief.org/patent/us/3102230/mosfet-field-effect-transistor) — This 1960 patent describes the fundamental structure of the MOSFET, the tiny electronic switch that powers every modern computer processor.
- [How Nichia Created the First Practical Blue LED Electrodes](https://patentbrief.org/patent/us/5563422/blue-led-gallium-nitride) — A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable.
- [How the First Infrared LED Was Invented](https://patentbrief.org/patent/us/3293513/infrared-led-biard-pittman) — Texas Instruments' 1962 patent for the first practical semiconductor diode that emits infrared light when electricity passes through it.
- [How Robert Moog Used Transistors to Shape Synthesizer Sounds](https://patentbrief.org/patent/us/3475623/moog-synthesizer-ladder-filter) — A 1969 invention by Robert Moog that uses the internal resistance of transistors to create the iconic filters that define the sound of analog synthesizers.