HP 12C
HP-12C
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| Type | Programmable Financial |
|---|---|
| Manufacturer | Hewlett-Packard |
| Introduced | 1981 |
| Cost | ca. USD 70,- |
| Calculator | |
| Entry mode | Classical RPN (4 stack level) |
| Display type | LCD seven-segment display |
| Display size | 10 digits |
| CPU | |
| Processor | Nut core (HP 1LF5 / HP 1LM2 / HP 1LQ9 / HP 1RR2 / Agilent/Marvell 2AF1) / ARM7TDMI core (Atmel AT91SAM7L128) / ARM Cortex-M4 core (Atmel ATSAM4LC2CA) |
| Programming | |
| Programming language(s) | keystroke programmable (fully merged) |
| Memory register | 7…20 (R0…R9/CF0…CF9, R.0…R.9/CF10…CF19) + 5 (n, i, PV, PMT, FV/CF20) + 5 (X, Y, Z, T, LAST X) |
| Program steps | 8…99 |
| Other | |
| Power supply | 4.5 V (3x LR44) or 3 V (1x or 2x CR2032) depending on model |
| Power consumption | 0.25 mW |
| Weight | 113 g |
| Dimensions | 128 × 79 × 15 mm |
| Type | Programmable Financial |
|---|---|
| Manufacturer | Hewlett-Packard |
| Introduced | 2003 |
| Cost | ca. USD 60,- |
| Calculator | |
| Entry mode | Classical RPN (4 stack level), Algebraic |
| Display type | LCD seven-segment display |
| Display size | 10 digits |
| CPU | |
| Processor | 6502 core (SPLB20D2 / 6502 core (GPLB31A) |
| Programming | |
| Programming language(s) | keystroke programmable (fully merged) |
| Memory register | original 12c Platinum model: 7…20 (R0…R9/CF0…CF9, R.0…R.9/CF10…CF19) + 5 (n, i, PV, PMT, FV/CF20) + 10 (CF21…CF30) + 5 (X, Y, Z, T, LAST X); later 12c Platinum variants: 7…20 (R0…R9/CF0…CF9, R.0…R.9/CF10…CF19) + 5 (n, i, PV, PMT, FV/CF20) + 60 (CF21…CF80) + 5 (X, Y, Z, T, LAST X) |
| Program steps | 8…400 |
| Other | |
| Power supply | 3 V (1x or 2x CR2032) depending on model |
The HP-12C is a financial calculator made by Hewlett-Packard (HP) and its successor HP Inc. as part of the HP Voyager series.
The HP-12C is HP's longest and best-selling product, in continual production since its introduction in 1981. Due to its simple operation for key financial calculations, the calculator long ago became the de facto standard among financial professionals. Its popularity has endured despite the fact that even a relatively simple, but iterative, process such as amortizing the interest over the life of a loan – a calculation which modern spreadsheets can complete almost instantly – can take over a minute with the HP-12C. The 1977 October edition of the HP Journal contains an article by Roy Martin, the inventor of the simple method of operation used in HP financial calculators, which describes, in detail, the mathematics and functionality built by William Kahan (from UC Berkeley) and Roy Martin that is still in use today.
Later HP financial calculators are many times as fast with more functions, but none have been as successful. The HP-12C's programming mode is very intuitive and works like a macro operation on a computer. Basically, the keys one would press in the calculating mode to arrive at a solution are entered in the programming mode along with logical operators (if, and, etc.) if applicable to the solution. After the programming is complete, the macro will run in the computation mode to save the user steps and improve accuracy. There are 99 lines of programmable memory on the HP-12C.
There were at least eight hardware revisions of the HP-12C since 1981 (including one special issue). Over its lifespan, the proprietary silicon on sapphire HP Nut (originally the 1LF5, then 1LM2) processor's technology has been redesigned to integrate all the circuitry into a single chip (first the 1LQ9, then 1RR2) and to refresh the manufacturing process (as the foundry could no longer manufacture the necessary chips, having moved on to making higher-density chips). However, HP's market research found in the late 1980s that users did not trust results obtained too quickly and so the CPU speed was never improved from the original 884 kHz, but the speed could be increased by a user modification. In the late 1990s, the CPU was changed to a 3 V process (Agilent 2AF1-0001, later a Marvell 2AF1-0002) and the battery was therefore changed to a single CR2032 cell replacing the three LR44 cells previously used (F1637A).
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