Sharp EL-811

Date of introduction:  1971 Display technology:  Fluorescent
New price:  $379 Display size:  8
Size:  6.9" x 4.2" x 1.8"    
Weight:  20 ounces Serial No:  2007663
Batteries:  EL-84 (6*AA NiCd) Date of manufacture:  year 1972
AC-Adapter:  EL-81 Origin of manufacture:  Japan
Precision:  8 (Mult. 16) Integrated circuits:  Rockwell 10572, 10573
Memories:  1    
Program steps:   Courtesy of:  Joerg Woerner

Sharp Electronics Corporation introduced end of the year 1969 with the EL-8 the first portable, battery operated calculator. It uses the same technology as the earlier desktop calculator QT-8D.

This EL-811 followed the EL-8 with about 18 month and uses a very similar architecture. Due to the big steps in IC-Technology (Integrated Circuits) the EL-811 sports more features (memory, 16 digit multiplication results) with only 2 ICs. From the complexity of the calculator it is very similar to the smaller Canon LE-10 featuring ICs from Texas Instruments.

Dismantling a Sharp EL-811 calculator manufactured in 1972 reveals a single-board design with the two main ICs labeled Rockwell 10572 and 10573 surrounded by three integrated display drivers and a connector for the display module.

The display itself makes use of individual Itron fluorescent tubes with the odd trademark segmentation of early Sharp calculators.

The same housing was used again with the EL-8102 introduced in 1974.

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