Sharp CT-500 Handheld Electronic Calculator

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This compact instrument combines a handheld electronic calculator, an alarm clock telling time in several time zones, and a stop watch. It has a metal case and lid and an array of twenty-four small rectangular plastic keys. Operated as a calculator, it has ten digit keys, a decimal point key, a % key, four arithmetic function keys, a square root key, a clear/clear entry key, three memory keys, a recall key, and an hours/minutes/seconds key. Keys also can be used in “clock” mode to set the location (time zone), time, date, and alarm time, and to turn the alarm on or off. An eight-digit LCD display is behind the keyboard.
Marks printed on the back of the calculator read in part: ELECTRONIC CALCULATOR (/) CT 500. The also read: SER NO 71063319 BM (/) PRODUCED BY (/) SHARP CORPORATION JAPAN.
The calculator fits in a plastic case lined with red felt. Text at the base of the front of the case reads: ELSI MATE. Text on the back at the base reads: MADE IN JAPAN.
[Advertisement], Los Angeles Times, June 25, 1978, p. Y17. Sharp CT-500 “world clock” on sale for $67.95.
Currently not on view
date made
ca 1978
Sharp Corporation
place made
Physical Description
plastic (keys; carrying case material)
metal (case material)
felt (lining for carrying case material)
overall: 1/2 in x 2 1/4 in x 3 in; 1.27 cm x 5.715 cm x 7.62 cm
ID Number
catalog number
accession number
Credit Line
Gift of John B. Priser
See more items in
Medicine and Science: Computers
Handheld Electronic Calculators
Computers & Business Machines
Data Source
National Museum of American History


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