Another great American company – a founder of ‘silicon valley’.
When the HP35 came out in 1973, it was a revelation, because it could do transcendental functions. Before that, I had to look up logarithms in the back of my Chemistry book. Actually, after that, too. Since the HP35 cost $400 (1973 dollars) I still looked up logarithms. After I got a job, I got an HP45. Fast forward 40 years. I got my HP 45 out to use for a class I’m teaching and couldn’t find the battery pack or charger. I bought a replacement battery pack on E-bay and charged it externally. This was very inconvenient so I made a charger with a custom made plug (For sale – see the HP Charger / Battery page). This experience reinforced my love for these machines. An excellent site for info about HP calculators is the Museum of HP Calculators. This is a great site, a wealth of information. They sell a 2 DVD set with tons of information about HP calculators, calculator programming, HP publications etc. I bought the DVD, and recommend it wholeheartedly.