Hewlett Packard Champion Series
From Wiki
Hewlett-Packard Champion Series Also called the "Clamshell" series after the hinged hard case that the calculator was built into. All were based on the Saturn processor with the RPL operating system (although only the scientific calculators were programmable). The hinged case was surprisingly robust except for the battery compartment cover which turned out to be a little fragile.
| Picture | Calculator | Years | Description |
|---|---|---|---|
 | HP-18C | 1986-1988 | Initial RPL offering and the first financial calculator since the 12C. First HP pocket calculator using algebraic logic. Includes HP's Solver; not programmable. |
 | HP-19B | 1988-1990 | Update to the 18C. Adds trig and some more financial functions |
 | HP-19BII | 1990-2001 | Just like the 19B, but with an option to use RPN |
 | HP-28C | 1987-1988 | Scientific programmable with 2K of RAM. First pocket calculator doing symbolic math |
 | HP-28S | 1988-1992 | Updates the 28C with 32K of RAM and a hierarchical system of storing user variables and programs |
