Hewlett-Packard HP-21 Handheld Electronic Calculator
date: label: date made
content: 1977
name: label: maker
content: Hewlett-Packard Company
notes: label: Description
content: This handheld electronic calculator, relatively small and simple for a calculator sold by Hewlett-Packard, was introduced on February 1, 1975 and sold through 1977. Designed as a successor to the HP-35, it was one a series of calculators of this size that also included the HP-22, HP-25, HP-25C, HP-27, and HP-29C. It has a tan plastic case with a black keyboard and thirty rectangular plastic keys. These include ten digit keys, a decimal point key, a display key (to indicate whether or not the result is to be displayed in scientific notation), and four arithmetic function keys that also serve as memory keys. Above these are the elongated enter key and twelve function keys, each of which can take on two meanings. The change sign/square root of x key, the enter exponent/pi key, and the clear x/clear key are left of the enter key. The function keys above this are for exchange/R(convert to rectangular coordinates), R (roll down)/P (convert to polar coordinates) , exponents/natural logs, storage/logs to the base 10, and recall/powers of ten. The back row of keys includes an inverse/ power key, three trigonometric function keys which also can serve as inverse trigonometric function keys, and a blue shift key. Behind the keyboard are two switches, one on/off and one for shifting between degrees and radians in angular measure. The twelve-digit LED display is behind the switches. A mark on the front edge reads: hp HEWLETT • PACKARD 21.
label: Description
content: The reverse side of the calculator has prongs for a power adapter/recharger as well as a battery compartment that holds a frame for two batteries. Stamped above the battery pack is the number: 1711S21227. The first four numbers of the serial number indicate that the calculator was made in the eleventh week of 1977. A tag at the base of the back reads: HEWLETT-PACKARD (/) MADE IN SINGAPORE (/) 2.5 V 500mW.
label: Description
content: The calculator is in a brown zippered leather-covered, cloth-lined carrying case. A mark on the front reads: hp HEWLETT• PACKARD.
label: Description
content: References:
label: Description
content: W.A.C. Mier-Jedrzejowicz, <I>A Guide to HP Handheld Calculators and Computers </I>, Tustin, California: Wilson/Burnett Publishing, 1997, pp. 46–47, 132.
label: Description
content: David G. Hicks, <I>The Museum of HP Calculators</I>, http://www.hpmuseum.org/, accessed July, 2014.
label: Description
content: Randall Neff and Lynn Tillman, “Three New Pocket Calculators: Smaller, Less Costly, More Powerful,” <I>Hewlett-Packard Journal</I>, November 1975, pp. 2-7, 12. Much of the issue is devoted to the HP-21, HP-22 and HP-25.
label: Location
content: Currently not on view
place: label: place made
content: Singapore
setName: label: See more items in
content: Medicine and Science: Computers
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content: Computers & Business Machines
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content: Handheld Electronic Calculators
creditLine: label: Credit Line
content: Gift of John B. Priser
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1987.0435.08
label: catalog number
content: 1987.0435.08
label: accession number
content: 1987.0435
objectType: label: Object Name
content: electronic calculator
physicalDescription: label: Physical Description
content: ceramic (display board material)
label: Physical Description
content: metal (circuitry material)
label: Physical Description
content: plastic (case; keys; switches; zipper material)
label: Physical Description
content: leather (carrying case material)
label: Measurements
content: overall in case: 4 cm x 10 cm x 15 cm; 1 9/16 in x 3 15/16 in x 5 29/32 in
label: Measurements
content: out of case: 3 cm x 6.5 cm x 13 cm; 1 3/16 in x 2 9/16 in x 5 1/8 in