Sinclair Scientific

Date of introduction:  August 1974 Display technology:  LED-stick
New price:   Display size:  5 + 2
Size:  5.5" x 2.8" x 1.4"
 112 x 51 x 14 mm3
Weight:  3.9 ounces, 58 grams Serial No:  
Batteries:  4*AAA Date of manufacture:  year 1974
AC-Adapter:   Origin of manufacture:  United Kingdom
Precision:  8 Integrated circuits:  TMC0805
Program steps:   Courtesy of:  Joerg Woerner
    Download manuals:   (UK: 3.6M Bytes)
  (UK: 3.9M Bytes)

The Sinclair Scientific, launched in August 1974, was a highly unusual calculator. It displays only in scientific notation - 5 digit mantissa, 2 digit exponent. Because of the way its processor (a custom chip from Texas Instruments) is designed, it relies on reverse Polish notation. This unusual method of mathematical problem solving meant that, for instance, to add 2 and 4, one had to enter 2, then 4, then the + symbol. There was no = key.
The Scientific Programmable was an advanced version launched in 1977, again using reverse Polish notation. It could handle programs of up to 24 steps and cost 29.95. 

Do get an impression about the valuable internal construction just take your time and watch the next four pictures carefully.

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Joerg Woerner, December 5, 2001. No reprints without written permission.