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News Archive - Friden 1150 Introduction Note

Friden 1150 Introduction Note
Electronics, February 19, 1968

A brief note announcing Friden's new 1150 printing electronic calculator. While the Friden 1150 was not really remarkable from the standpoint of features, it was rather remarkable as it, at least as is known today, was the first printing electronic calculator with its logic fully implemented using integrated circuits.

Friden carried forward the counter-based stack (RPN) architecture from it's first-generation discrete transistor-based EC-130 and EC-132 electronic calculators, but worked with Texas Instruments (TI) to implement the three counters using three custom-made medium-scale TTL integrated circuits, one for each counter circuit. The remainder of the 1150's logic was implemented using TI's small-scale DTL and TTL integrated circuits. The only discrete component circuitry in the machine was in the power supply, drive circuitry for the printing system, and the write driver/ read amplifier for the magnetostrictive delay line used to store the calculator's working registers.

Friden also developed its own rather unique printing mechanism that utilized a moving carriage containing a print wheel with the digits zero through nine, decimal point, and operation symbols embossed on its circumference that spun at 3,600 RPM. The symbols on the print wheel were inked by a special roller that would transfer ink from a special ink cartridge. A single hammer that moved with the carriage, but positioned behind the paper, would fire just as a desired symbol would be positioned on the print wheel so that the paper would instantly press against the embossed symbol, causing it to be printed on the paper. The carriage moves right to left across the width of the paper to allow all of the necessary symbols to be printed at the rate of 37 characters per second.

See the Old Calculator Museum's exhibit on the Friden 1152 for information on slightly later programmable version of the 1150 that used the same technologies.