HP-35
More info
- Manufacturer
- Hewlett-Packard
- Released
- Type
- Pocket calculator
Hewlett-Packard's first scientific pocket calculator, 1972, which made the slide rule obsolete almost overnight.
Released in 1972 as the world's first handheld calculator with trigonometric and logarithmic functions — previously the preserve of a desktop machine or a slide rule. Bill Hewlett wanted one that fit in a shirt pocket, and its 35 keys gave it the name. It cost $395, and HP's own market study said nobody would buy it.
It sold in the hundreds of thousands anyway and buried the slide rule as an engineering tool. The HP-35 used Reverse Polish Notation — operands first, operator last — which stayed an HP signature for decades. An early firmware bug miscomputed certain logarithms; HP offered a free replacement to anyone who asked, which most owners never bothered to.