How Wang An Invented the Magnetic Pulse Memory Core
A 1949 invention by An Wang that used magnetic cores to store and transfer binary data, forming the backbone of early computer memory.
Original patent title: “Pulse transfer controlling device”
A 1949 invention by An Wang that used magnetic cores to store and transfer binary data, forming the backbone of early computer memory. Granted to Individual in 1955 with 74 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
This device uses magnetic cores to control the transfer of electrical pulses. It functions as a memory element by shifting information from one magnetic state to another. By applying specific current pulses, the device can store a bit of data as a magnetic orientation and then transfer that state to the next element in a sequence. This mechanism allowed early computers to store and move data without relying on fragile vacuum tubes.
The gap
What does this patent NOT cover?
- Does not cover semiconductor-based RAM or flash memory storage.
- Does not cover optical data storage or laser-based reading methods.
- Does not cover software-based data processing algorithms.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
It solved the problem of how to move data bits through a system without them getting lost or corrupted, using the physical property of magnetic hysteresis to hold a state indefinitely.
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
Magnetic core memory modules in 1960s mainframe computers
Early digital calculators
Control systems for the Apollo Guidance Computer
Why it matters
The bigger picture
This invention was fundamental to the development of reliable digital computers. Before this, memory was bulky and prone to failure. An Wang's work enabled the creation of magnetic core memory, which was the standard for high-speed computer storage from the 1950s through the 1970s.
Filed
October 21, 1949
Granted
May 17, 1955
Market context
Who's building on this
Companies in this space
Wang Laboratories became a major force in the computer industry based on this and related patents. While modern computing has moved to silicon, the logic of pulse-based data transfer remains a foundational concept in electrical engineering.
Market impact
This patent helped trigger the transition from vacuum tube machines to solid-state magnetic memory. It established the technical feasibility of reliable, non-volatile memory, which was essential for the growth of the mainframe computer market.
Claim 1 — Plain English
What this patent covers
This device uses magnetic cores to control the transfer of electrical pulses. It functions as a memory element by shifting information from one magnetic state to another. By applying specific current pulses, the device can store a bit of data as a magnetic orientation and then transfer that state to the next element in a sequence. This mechanism allowed early computers to store and move data without relying on fragile vacuum tubes.
The clever bit
It solved the problem of how to move data bits through a system without them getting lost or corrupted, using the physical property of magnetic hysteresis to hold a state indefinitely.
What it does not cover
- Does not cover semiconductor-based RAM or flash memory storage.
- Does not cover optical data storage or laser-based reading methods.
- Does not cover software-based data processing algorithms.
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
Early stage
Citation count
37/40
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
$25K – $81K
Midpoint $50K · 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
An, W. (1955). How Wang An Invented the Magnetic Pulse Memory Core (U.S. Patent No. 2,708,722). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2708722/magnetic-core-memory-wang
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 How Wang An Invented the Magnetic Pulse Memory Core cover?
A 1949 invention by An Wang that used magnetic cores to store and transfer binary data, forming the backbone of early computer memory.
Who owns patent US 2708722?
Individual owns this patent, granted in 1955.
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 2708722 cited by?
This patent has been cited by 74 later patents that build on its ideas.
What problem does this patent solve?
This invention was fundamental to the development of reliable digital computers. Before this, memory was bulky and prone to failure. An Wang's work enabled the creation of magnetic core memory, which was the standard for high-speed computer storage from the 1950s through the 1970s.
What does this patent NOT cover?
Does not cover semiconductor-based RAM or flash memory storage.
Same assignee
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