Texas Instruments (TI) SR-10



In the end of 1972, Texas Instruments launched the first scientific pocket calculator, which was made in several versions. The SR-10 displayed here belongs to the second version, which was made in Italy.
This version carries the "SR-10" logo on the keyboard plate.


The SR-10 offers an inside view, which is typical for pocket calculator of that age: Inside, there's a case-filling PCB, on which a handful of ICs (TMS 0120NC as CPU and four display driver SR75494N, which were made in December 1973), many transistors and even more diodes and resistors are mounted.

back side
back side

Unlike the other simpler pocket calculators, the SR-10 offered an extended calculating range (up to 10^99) and a square and square root function. The entries are made by standard algebraic entry logics, where at the end of a calculation, the "=" key has to be pressed. A wrong entry can corrected by the "CD" key.

inside and batteries
inside and batteries

The SR-10 works with three NiCD accus, which can be loaded by an external power device. The socket is secured against wrong poling by a diode.
Unfortunately in the SR-10 displayed here, the accus (the original ones as well as the replacement accus) leaked and did not only corrode the contacts, but damaged the electronics so much, that only the pattern is displayed - maybe this is familiar to you and you can help in restoring my SR-10?

does not work any more...
does not work any more...

Technical data

ManufacturerTexas Instruments (TI)
Display8+3 digit LED
Number of keys 23
Functions+-*/ INV SQRT SQR
Entry logicALG
Power supply 3xAA (internal)
Serial Number040835

Computermuseum Kiel: Texas Instruments Erscheinungs-Liste (de) (Timetable of the TI calculators of the 1970ies)
Datamath: SR-10 (en) (Extensive description of the SR-10)
The Clip Collection: TI SR-10 (en) (a few photos)
Thimet-Taschenrechnersammlung: SR-10 (en) 
Vintage Calculators Web Museum: TI Calculators (en) (How rare are TI calculators? This page gives you the answer)
Vintage Calculators Web Museum: TI SR-10 (en) (Description with some fotos)
Vintage technology: TI SR-10 (en) (Very extensive description)
Vintage-Calc: TI SR-10 (french page about the SR-10)
XNumber: SR-10 (en)