DATAMATH CALCULATOR MUSEUM
Texas Instruments SR-50
|Date of introduction:||January 15, 1974||Display technology:||LED modules + lens|
|New price:||$169.95, DM 520.00||Display size:||10 + 2|
|Size:|| 5.8" x 3.2" x
147 x 81 x 32 mm3
|Weight:||8.5 ounces, 240 grams||Serial No:||211917|
|Batteries:||BP1||Date of manufacture:||wk 42 year 1974|
|AC-Adapter:||AC9200||Origin of manufacture:||USA|
|Precision:||13||Integrated circuits:||TMC0501, TMC0521|
|Program steps:||Courtesy of:||Joerg Woerner|
US: 2.2 MByte)
DE: 1.9 MByte)
|Download manual:||(US: 5.6 MByte)|
The wonderful electronic slide rule SR-50 marked a milestone in the history of calculators manufactured by Texas Instruments. It added trigonometric and hyperbolic functions, the logarithms and their inverses to the scientific functions of the SR-10, SR-11 and SR-16 line of calculators. The calculator was placed with big success against Hewlett-Packard's HP-35 and produced in high quantity. The internal construction was very rigid compared with other models. To reduce manufacturing costs and to give a similar appearence to the SR-52 and SR-56 calculators the SR-50 was replaced within 18 month with the SR-50A. Don't miss the rare SR-51.
On a first view the twins SR-50 and SR-50A look similar, but
if you use them you'll feel the differences! If you search for the best SR-50,
choose a model produced later than July 1974. Engineers at Texas Instruments
changed the calculation algorithms and achieved a higher precision. Please find the comparision in the
With the TMC0501 building blocks Texas Instruments created a novel architecture for scalable scientific calculators. The architecture used minimum a 2 chip design with the Arithmetic chip and the SCOM (scanning read only memory) but was expandable to a maximum of 8 SCOM's, additional RAM as program memory for programmable calculators, additional RAM for general purpose registers and even a chip driving a printer. Most scientific and programmable calculators from Texas Instruments between the years 1974 and 1982 like the SR-51, SR-60A and TI-59 use these chips. Please find all known calculators using the TMC0501 architecture here. Don't miss the odd TI-5230 desktop calculator.
Masaki Takada donated some wonderful pictures and this gives us the opportunity to view the inside of the SR-50.
|Engineers use the clear case during the development of a product to check if the electronic and mechanical components fit neatly into the housing.|
|The side view gives you an impression of the upper and lower case shell and the printed circuit boards inside.|
|The bottom view gives you (from upper right to lower left) the opening of the rechargable batteries, the huge calculator chips (TMC0501, TMC0521) and the power supply circuit.|
|The display frame covers the upper row of the keys and the two switches neatly. This gives you a very valuable design compared to e.g. the TI-30.|
|This wonderful pictures gives you an imagination of the curved lens above the red display. A perfect calculator!|
If you have additions to the above article please email: firstname.lastname@example.org.
© Joerg Woerner, December 5, 2001. No reprints without written permission.