Friden Model EC - 130 (1964)

"Friden and Marchant Rotary Calculator were fast and easy to operate. No counting cycles for multiplication or division. The carriage at the top of the calculator would step over for multiple addition or subtraction. The answer was available instantly in the rotary numbers in the carriage. We used a marchant rotary calculator in the 1930's and 1940's to determine the value of a truck load of tomatoes in the family tomato canning factory. There were several tomato canning plants in Indiana in 1930's and 1940's, including Louden Company on South 3rd street. That was when South 3rd street was undeveloped. 7th street was US highway 41. The building currently remodeled on the river north of Cherry street was American Can Company, where they made cans. I was furnished a marchant calculator for my work at Quaker Maid in late 1950s."
- Gerald Dix

Carl Friden (1891-1945) was a young Swedish engineer who arrived in the USA (via Australia) towards the end of the 1914-18 war. He found work with Marchant, and earned substantial royalties from his inventions. He sold his interests back to Marchant in around 1930, and established his own Friden Calculating Machine Company in 1933.

Friden based his new machine on the long-established uni-directional stepped-drum mechanism, with subtraction accomplished via differential reversing gears on the registers. The "Friden Roto-Flow One-way Drive", like the contemporary Swiss MADAS machine, was essentially a modern implementation of the 19th-century Thomas Arithmometer. Friden rented a factory in Oakland (California) in December 1933, and produced the first calculator to his new design in June of 1934. Rapid expansion and development led to a much-improved Model C in 1935, a new purpose-built factory in San Leandro in 1937, and a fully-automatic Model ST in 1939.

Calculator production continued during the war years, but the company also played a major role in the manufacture of precision machine tools, ordnance, and aircraft instruments. Carl Friden died in 1945 (aged only 54), but his company went on to continued successes, most notably with the Model STW fully-automatic calculator of 1949, the Model SRW square-root calculator of 1952, and the EC-130 electronic calculator of 1964.

In the late 1950s Friden acquired the Commercial Controls company and its "Flexowriter" product range. The Flexowriter was basically an up-market teleprinter consisting of an IBM electric typewriter with a paper-tape reader and punch mechanism. The company developed these machines in several directions, including a primitive word processor system, a "Computyper" billing system interfaced to an electronic calculator, and a tape-operated typesetting system. Many of the calculator instruction manuals from this period were typeset on the Friden "Justowriter". The company became the "Friden Division of Singer" in 1963, then "Singer Business Machines", but disappeared in the early 1970s as the mechanical product lines were overtaken by computer-based systems.

Friden Model EC-132, S/N 2811A
Functions: ASMD, square root, 1 memory
Technology: Discrete-component, delay line memory
Display: 13 digits, 4 registers, CRT display
Dimensions: 18-1/2"W x 22"D x 10"H, weight 43 pounds
Manufactured: Friden, USA, 1965

The Friden EC-130 from 1964 was one of the very first all-transistor electronic calculators. The circuitry was built entirely with discrete components, with internal storage provided by a mechanical delay line memory. The calculator used "reverse Polish" notation, with the four stack registers visible simultaneously on a cathode ray tube display.

The Model EC-132 from 1965 was basically identical to the EC-130, but with the addition of an automatic square root function.

The EC-132 illustrated was purchased in 1966 by the Australian Mineral Development Laboratories, at a price in the thousands of dollars. It was obsolete and sold for scrap within three years.

Friden EC-132 internal view (30kb)