Sharp EL-816

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After Sharp, in cooperation with US-based Rockwell International, built its first small calculator with LSI circuits (QT-8D) in 1970, followed by a palm-sized smaller version (EL-8 and then EL-8M with memory), Rockwell tried reducing number of circuits to allow its Japanese partner to mass-produce pocket calculators. By early 1972, the EL-811, which had two chips instead of the previous five, and its pocket-sized version, the EL-812, were completed. In the production of VFD displays, preference was given to the seven-segment design — which has initially eight segments due to the extension of the horizontal line of ’four’ —, so the EL-811 was redesigned to use thes displays, and then an one-chip version with K key (for switching contant register on and off) was completed in 1973 (EL-816).

We can see how the Rockwell-Sharp collaboration, which had shown a truly revolutionary technological advantage just three years earlier, was at a disadvantage to domestic and foreign manufacturers using “single-chip” calculator circuits, which have already manufactured by MOSTEK and Texas Instruments at the time: the first pocket calculators with these chips appeared as soon as 1971. Rockwell focused on more advanced (scientific, financial etc.) calculators, and Sharp was able to maintain its prestigious position by relying on the domestic market, which is slowly leaving the American background industry behind.

The EL-816, along with its predecessors (EL-811, EL-812), has an eight-digit capacity, but when multiplying, all sixteen digits of the result can be displayed by pressing and holding the ↔ key. The second eight digits of the multiplication are no longer stored in the memory register, so the independent memory can be used during any operation. In August 1973, the EL-816 was replaced by the EL-816S with modified electronics. In 1974, a version with Japanese circuit, which was capable for square root calculation, was released under the type designation EL-8102.