Hewlett-Packard HP 91 (Topcat FELIX)
The Hewlett-Packard HP 91 is a scientific calculator with 12 digits precision and RPN (reverse polish notation) logic. It has 56 functions, 42 keys, and an LED (light-emitting diode) display, typical of calculators of this era. The power source is 4x1.2V NiCd battery pack.
Facts at a glance:
|Power Source||4x1.2V NiCd battery pack|
If you have a Hewlett-Packard HP 91 that is no longer working, you can consider replacing the calculator with a modern equivalent. We suggest the following current model as a replacement: