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Ab/c: Fractions calculation
AC: Alternating current BaseN: Number base calculations Card: Magnetic card storage Cmem: Continuous memory Cond: Conditional execution Const: Scientific constants Cplx: Complex number arithmetic DC: Direct current Eqlib: Equation library Exp: Exponential/logarithmic functions Fin: Financial functions Grph: Graphing capability Hyp: Hyperbolic functions Ind: Indirect addressing Intg: Numerical integration Jump: Unconditional jump (GOTO) Lbl: Program labels LCD: Liquid Crystal Display LED: Light-Emitting Diode Li-ion: Lithium-ion rechargeable battery Lreg: Linear regression (2-variable statistics) mA: Milliamperes of current Mtrx: Matrix support NiCd: Nickel-Cadmium rechargeable battery NiMH: Nickel-metal-hydrite rechargeable battery Prnt: Printer RTC: Real-time clock Sdev: Standard deviation (1-variable statistics) Solv: Equation solver Subr: Subroutine call capability Symb: Symbolic computing Tape: Magnetic tape storage Trig: Trigonometric functions Units: Unit conversions VAC: Volts AC VDC: Volts DC |
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The SR-50 was Texas Instrument's first full-featured scientific calculator. It was the company's response to the challenge presented by the Hewlett Packard 35.
The SR-50 is a sleek, very well designed scientific calculator with a large, 10+2 digit display. Unlike later Texas Instruments models of similar appearance that felt like a creaky box of cheap plastic, the SR-50 has a solid, instrument-quality feel.
Despite its historic significance, the SR-50 would normally fall outside my main area of interest, programmable calculators. However, once again I was unable to resist when I was presented with the opportunity to obtain a specimen in excellent condition (as the image on the right shows, the silver trim is entirely intact, which is quite a rarity) at a bargain price.
There is also another reason: the SR-50 belongs to a family of four calculators that are closely related to the first line of programmable calculators (including the SR-52 and SR-56) from Texas Instruments. Of these, the SR-50 and SR-51 have an almost identical appearance; the same is true for the SR-50A and the SR-51A. However, it is the SR-51 and SR-51A that have a connector in the battery compartment which can be used with the PC-100 printer cradle, when the printer is switched to SR-52 compatibility mode. I don't have any documentation with my SR-51 or SR-51A (I received the SR-51 as a gift, and obtained my SR-51A by chance, advertised as non-working, along with an SR-52) but the lack of any printer-related keys on its keyboard appear to suggest that printer compatibility might not have been officially supported. It also makes one wonder: are there any other functions this calculator may have that aren't accessible from its keyboard? If only I knew the specifications for the bidirectional PC-100 printer interface...
The SR-51A was also the first calculator I ever saw that had a built-in random number generator. One also gets the feeling that its conversion functions (2nd followed by a two-digit number) are in fact implemented as ROM-based programs that are not unlike the keystroke programs on programmable models.
Incidentally, the SR-51 had two other variants, however, these more properly belong to the next generation of Texas Instruments scientific calculators, with a much cheaper construction. The SR-51-II is a non-programmable scientific calculator, but the TI-51-III is actually identical to the TI-55, with minimal programmability.
