# How Texas Instruments Invented the Handheld Electronic Calculator > This 1972 patent describes the architecture for the first truly portable, battery-powered electronic calculator that could fit in a pocket. - **Patent:** US 3819921 - **Original title:** Miniature electronic calculator - **Owner:** Texas Instruments Inc - **Granted:** 1974 - **Status:** Public domain (expired) - **Times cited:** 18 - **Field:** consumer_electronics, semiconductors, mechanical ## What it does The patent details a system that shrinks bulky desktop calculator components into a handheld device. It uses an integrated semiconductor circuit array—a single chip—to handle memory storage, arithmetic operations like addition and division, and control signaling. The design stacks the keyboard, the circuit array, and the display in parallel planes to minimize the device's footprint. This allows the calculator to process multi-digit numbers and display results on a small screen or via a thermal printer while running on battery power. ## What it does NOT cover - Does not cover non-electronic or mechanical calculators (e.g., slide rules or abacuses). - Does not cover calculators that require external power sources or wall outlets. - Does not cover computing devices that lack a physical keyboard input mechanism. - Does not cover general-purpose computers or microprocessors not specifically configured for arithmetic calculation. ## The clever bit The innovation was the spatial arrangement of the components. By aligning the keyboard and the integrated semiconductor array in parallel planes within a pocket-sized housing, the inventors achieved a level of density that made portable digital math possible for the first time. ## Real-world examples 1. Texas Instruments TI-2500 Datamath 2. Early handheld electronic calculators of the 1970s ## Why it matters This invention marked the transition of computing from room-sized machines to personal, portable tools. It proved that complex integrated circuits could be mass-produced for consumer electronics, paving the way for the modern smartphone and all handheld digital devices that followed. ## Frequently asked questions ### What does How Texas Instruments Invented the Handheld Electronic Calculator cover? This 1972 patent describes the architecture for the first truly portable, battery-powered electronic calculator that could fit in a pocket. ### Who owns patent US 3819921? Texas Instruments Inc owns this patent, granted in 1974. ### 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 3819921 cited by? This patent has been cited by 18 later patents that build on its ideas. ### What problem does this patent solve? This invention marked the transition of computing from room-sized machines to personal, portable tools. It proved that complex integrated circuits could be mass-produced for consumer electronics, paving the way for the modern smartphone and all handheld digital devices that followed. ### What does this patent NOT cover? Does not cover non-electronic or mechanical calculators (e.g., slide rules or abacuses). **Full plain-English explainer:** https://patentbrief.org/patent/us/3819921/barcode-upc-scanner **Original patent:** https://patents.google.com/patent/US3819921 --- _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: - [How Jack Kilby Invented the First Integrated Circuit](https://patentbrief.org/patent/us/3138743/kilby-monolithic-integrated-circuit) — Texas Instruments' 1959 patent for the first integrated circuit, which combined transistors and resistors on a single piece of semiconductor material. - [Hamilton's Early Digital Watch with LED Display](https://patentbrief.org/patent/us/3672155/digital-watch-pulsar) — Hamilton's 1972 patent for a digital watch that uses electronic circuits and light-emitting diodes (LEDs) to show time, instead of gears and hands, powered by a rechargeable battery. - [How the ENIAC Computer Processes Data Using Electronic Pulses](https://patentbrief.org/patent/us/3120606/eniac-electronic-computer) — A foundational 1964 patent describing how the ENIAC computer used sequences of electronic pulses to store, read, and process numerical and qualitative data. - [How Liquid Crystal Displays (LCDs) Were Invented](https://patentbrief.org/patent/us/3322485/lcd-liquid-crystal-display) — This 1962 patent describes the first practical way to use organic liquid crystals to create a display that scatters light when an electric current is applied. - [How a Spring-Loaded Pocket Dispenser Works](https://patentbrief.org/patent/us/2620061/pez-dispenser) — A 1949 mechanical design for a pocket-sized container that uses a spring to push items like pills or candies to the top for easy access.