Friden Calculating Machine Company (Friden, Inc.) was founded by Carl Friden in San Leandro, California in 1934. Friden electromechanical calculators were robust and popular. In 1952 Friden introduced a machine with square-root capability. San Leandro is a city located in Alameda County, California. ... A modern basic arithmetic calculator For other uses, see Calculator (disambiguation). ...

Friden went on to introduce the first fully transistorized desktop electronic calculator, model EC-130 in June 1963. This machine had a 13-digit capacity and a 5-inch CRT display. It used a form of acoustic delay line for memory, to save money on expensive transistors. The EC-130 sold for $2200, about three times the price of comparable electromechanical calculators of the time. It was the first calculator to use reverse Polish notation (RPN), which eliminated the need for parentheses to specify the order of operations in complex calculations. The model EC-132 added a square root and reciprocal functions. In 1965 the company was purchased by the Singer Corporation. Assorted transistors The transistor is a solid state semiconductor device that can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. ... CRT can mean: Cathode Ray Tube, in electronics, a display device (such as those used in one type of television) C Run-Time, in computing Charitable Remainder Trust, in Law Chinese Remainder Theorem, in mathematics Corneal Refractive Therapy, in medicine Criterion-referenced test, in U.S. schools Critical race theory... Delay line memory was a form of computer memory used on some of the earliest digital computers, such as the EDSAC and UNIVAC I. The first such systems consisted of a column of mercury with piezo crystal transducers (a combination of speaker and microphone) at either end. ... Reverse Polish notation (RPN) , also known as postfix notation, is an arithmetic formula notation, derived from the Polish notation introduced in 1920 by the Polish mathematician Jan Łukasiewicz. ... For the round brackets used in punctuation, often called parentheses, see bracket. ... In arithmetic and algebra, certain rules are used for the order in which the operations in expressions are to be evaluated. ... A Singers sewing machine // History Singer Corporation was established as I.M. Singer & Co. ...

External links

• Friden STW-10 Electromechanical calculator sold from 1949–1966
• Friden EC-130 Electronic calculator (1963)
• Friden/Singer 1112 with 507 transistors and twelve digit Nixie tube display, designed and built by Hitachi