Happy 25th Anniversary, HP-12C Calculator
In 1981, Hewlett-Packard introduced the HP-12C financial calculator, and it became the standard financial calculator used by financial anlaysts, mortgage bankers, stock analysts, bond traders, accountants, real estate brokers, MBA students, finance and accounting majors, etc.
The HP-12C orignally sold for $150, it now sells for $70.
The goal of developing the 12C was to have a sophisticated programmable financial calculator, that would be small enough to fit in a shirt pocket, would have long battery life and would meet the HP "drop test" - the ability to withstand a fall from a desktop onto a concrete floor. HP worked with several researchers with Ph.D.s in numerical analaysis, mathematics, electrical engineering and computer science to develop the 12C.
The decision was made, for the ultimate mathematical and computational efficiency, to use RPN (Reverse Polish Notation) for data entry, instead of the traditional algebraic entry. For example, instead of 2 + 2 = 4 (algebraic entry), RPN entry would be 2 ENTER 2 + (mathematical operation comes last). Although mathematicians and engineers were comfortable with RPN, HP was concerned that finance professionals would have trouble accepting RPN, but the calculator became a huge success, and is still used widely today.
In 2003, HP introduced the Platinum 12-C that uses either RPN or algebraic. Although once you learn RPN, I can guarantee that you will NEVER go back to algebraic, it is TOO slow.
For the 25th anniversary of the 12C, HP recently introduced a limited edition 12C model for $80, with both RPN and algebraic, with a beautiful leather case.
Here is HP's backgrounder on the 12-C.
Here is an explanation of RPN.
BTW, I own 2 original 12Cs, one platinum 12C, 2 two of the new 25th anniversary 12C, one HP 10B and one HP 10BII.