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Sinclair Scientific &
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Inside Scientific

Sinclair Scientific

Displays only in scientific notation - 5 digit mantissa, 2 digit exponent, red LED (made by Bowmar).

4-function, limited scientific, reverse-Polish notation (RPN).

Main integrated circuit: Texas Instruments TMC0805 (here date coded to 1974, week 18).

6v (4 x AAA batteries).

50 x 111 x 19 mm (2.0 x 4.4 x 0.75 ins).

Made in England.

"Cambridge" series size, but not to be confused with the Cambridge Scientific.

Introduced 1974, initial price was 49 [about US$80] + Value Added Tax  (VAT), but the receipt for one example bought in July 1976 shows that it cost just 7 [about US$14] including VAT.

Was also available as a build-it-yourself kit, see below.

Great ingenuity was needed to shoehorn the program for scientific functions into the ROM of the TMS0805 chip, which was designed for use in basic four-function calculators.  More information about this achievement appears in the Sinclair Scientific page in the Featured Hand-held Calculators section.

Sinclair Scientific Kit

A Sinclair Scientific calculator kit, still shrink-wrapped in the polystyrene container.

Sinclair Scientific Kit
Sinclair Scientific Kit

The assembly instructions for the Sinclair Scientific calculator kit and the soft carrying pouch.

The components of the Sinclair Scientific calculator kit, there is also a bag of small parts out of view.

Giant Scientific

Giant scientific calculator

This amazing machine is a giant Sinclair Scientific calculator. It has the functionality of the hand-held model, but has the enormous size of 12" x 27" (30cms x 68cms).

Powered by 240v AC, it has a display formed of an array of dozens of discrete LEDs.

Grateful thanks go to Henry Padolsey for providing these incredible photographs.


This interesting photograph shows the array of discrete LEDs which make up the display, with the electronics boards below, all mounted on a substantial wooden back.

Display & circuit boards.

A close up showing the display LEDs and the electronics boards.

Vintage Calculators

© Text & photographs copyright Nigel Tout   2000-2019  except where noted otherwise.