Texas Instruments SR-40
Brief History
Rivalry between Hewlett-Packard and Texas Instruments caused introducing newer and newer scientific calculators. Because Texas Instruments did not produce scientific calculator circuits for other companies, Rockwell hit the market in 1974 with its own chips and made possible dozens of companies producing cheap "electronic slide rules" So in 1976 Texas Instruments introduced two new scientific models with identical circuitry: SR-40 with rechargeable batteries for professional purposes, and the cheaper TI-30 which can be operated from a 9V battery. Its novelty was the single PCB with only one chip and the integrated LED display module. TI-30 was in production for years, in 1980 it was replaced with the TI-30 LCD which uses liquid crystal display.
| Manufacturer: | Texas Instruments (USA) |
| Mfg. date: | 1976 |
| Size: | 8×14,7×3,4 cm |
| Weight (ready for operate): | n.a. |
| Type: | scientific |
| Capacity: | 8/5+2 digits (input/display) 10+2 digits (internal precision) |
| Operating logic: | AOS |
| CPU: | Texas Instruments TMC0981NL |
| Registers: | 3 standard (with saving the pending operation) 1 constant (with saving the pending operation) 15 bracket (with saving the pending operation) 1 memory (with aritmetic) |
| Features: | %calculation with percent +/-change sign (direct entry of negative numbers) Ffloating-point notation Sciscientific (exponential) notation Sqrsquare root x2square pivalue of pi (3.1415..) can be recalled 1/xreciprocal trigtrigonometrical functions (sin, cos, tan and inverses: arcsin, arccos, arctan) logexponential and logarithmical functions (10- and e-base) yxraising to power |
| Display: | 9 digit LED |
| Power: | battery pack or adaptor |
| Test results: | trigonometry:result of sin-1(cos-1(tan-1(tan(cos(sin(60°)))))), reference value: 60. 60.028581744 exponential:result of 0.999160000, reference value (first 14 digits): 3.0068804206375×10-70 3.006980772E-70 |
SR-40
Inside of the SR-40
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