Distinctive features: The first hand-held, programmable calculator.
Display uses scientific notation, 10 digits mantissa, 2 digits exponent, red LED.
Scientific, programmable, with 100 program steps.
3.6v (3x AA rechargeable cells in a battery pack).
80 x 149 x 36 mm (3.2" x 5.9" x 1.4").
Launched in January 1974.
Made in USA.
This was the first hand-held programmable calculator. Programs can be stored on magnetic cards, see photographs below, though these had been used previously with desktop programmable calculators. Program libraries for performing calculations for various disciplines could be purchased from HP.
Above, "Compound Interest" program about to be read from the magnetic card. The card is driven through the calculator by a tiny motor inside, from right to left.
Left, after the program has been read in, the card is inserted in a slot below the display and there provides the legends for the keys A to E.
The HP-65 is described in considerable detail in the Hewlett-Packard Journal of May 1974.
There is an enormous amount of information about the HP-65 gathered by David Hicks at the Museum of HP Calculators at https://www.hpmuseum.org/hp65.htm.
A Guide to HP Handheld Calculators and Computers
Revised Guide to HP Calculators Available
The fifth edition of Wlodek Mier-Jedrzejowicz's "A Guide to HP Handheld Calculators and Computers" has been published.
© Text & photographs copyright Nigel Tout 2000-2023 except where noted otherwise.