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Hewlett-Packard HP 21 (Woodstock PUMPKIN)

Hewlett-Packard HP 21

The Hewlett-Packard HP 21 is a scientific calculator with 12 digits precision and RPN (reverse polish notation) logic. It has 25 functions, 30 keys, and an LED (light-emitting diode) display typical of calculators of this era. The power source is 2xAA NiCd battery pack. A sample of this calculator is held in the calculator.org collection.

Facts at a glance:

FeatureValue
TypeScientific
Functions25
Keys30
Precision12
LogicRPN
Display typeLED
Length129mm
Width67mm
Thickness29mm
Weight170g
Power Consumption0.500000W
Power Source2xAA NiCd battery pack
Year introduced1975
Year discontinued1978

Replacements:

If you have a Hewlett-Packard HP 21 that is no longer working, you can first try replacing the 2xAA NiCd battery pack batteries. If that doesn't solve the problem, then you can consider replacing the calculator with a modern equivalent.

We suggest the following current model as a replacement:

See other calculators by Hewlett-Packard