United States Patent 3,819,921
June 25, 1974

Miniature Electronic Calculator
Jack S. Kilby
Jerry D. Merryman
James H. Van Tassel

Filed December 21, 1972
Image of US PATENT 3,819,921

Abstract of the Disclosure

Binary-coded decimal electronic calculator capable of adding, subtracting, multiplying and dividing with some degree of automatic decemal point placement to provide a visual display of answers of up to 12 decimal digits. The decimal digits are serially displayed at a speed compatible with the calculator operations. The parts of the calculator are so adapted electrically and mechanically in relation to each other to result in a miniature portable battery operated calculator of extremely small dimensions, for example the outside case dimensions of 4-1/4 inches by 6-1/8 inches by 1-3/4 inches and very low weight of about 45 ounces, having a calculating capability only before obtainable in calculators of much larger size and weight while retaining mechanical and operational simplicity. Some significant aspects of the calculator are the primary electronics embodied in an integrated semiconductor circuit array located in substantially one plane for performing the arithmetic calculations and generating the control signals, a keyboard input arrangement located in substantially one plane parallel to the integrated semiconductor circuit array for producing unique electrical signals corresponding to number and command entries and a visual display using a semiconductor array, as for a thermal printer for printout.
Figure descriptions: cover graphic

  • illustrates a block diagram of the arithmetic section of the integrated semiconductor circuit array of the calculator.

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National Museum of American History
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