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A pinwheel calculator is a class of mechanical calculator described as early as 1685, and popular in the 19th and 20th century, calculating via wheels whose number of teeth were adjustable. These wheels, also called pinwheels, could be set by using a side lever which could expose anywhere from 0 to 9 teeth, and therefore when coupled to a ...
Odhner thought of his machine in 1871 while repairing a Thomas' Arithmometer (which was the only mechanical calculator in production at the time) and decided to replace its heavy, bulky Leibniz cylinder by a lighter, smaller pinwheel disk. This is why the two machines share the same name but look completely different.
The Leibniz wheel was used in many calculating machines for 200 years, and into the 1970s with the Curta hand calculator, until the advent of the electronic calculator in the mid-1970s. Leibniz was also the first to promote the idea of an Pinwheel calculator. [7]
The Texas Instruments TI-30 calculator retailed for $24.95 in 1976 at O’Neil's department store in Akron.
Was the first scientific calculator to fly in space in 1973. [5] HP-35 calculators were carried on the Skylab 3 and Skylab 4 flights, between July 1973 and February 1974. [6] Is the first pocket calculator with a numeric range that covered 200 decades (more precise 199, ±10 ±99). [5]
The TI-59 is an early programmable calculator, that was manufactured by Texas Instruments from 1977. It is the successor to the TI SR-52, quadrupling the number of "program steps" of storage, and adding "ROM Program Modules" (an insertable ROM chip, capable of holding 5000 program steps).
In the position shown, the counting wheel meshes with three of the nine teeth of the Leibniz wheel. A Leibniz wheel or stepped drum is a cylinder with a set of teeth of incremental lengths which, when coupled to a counting wheel, can be used in the calculating engine of a class of mechanical calculators.
SR-50 (1974) Printed circuit board. Data code 035: 3rd week 1975. The SR-50 was Texas Instruments' first scientific pocket calculator with trigonometric and logarithm functions. . It enhanced their earlier SR-10 and SR-11 calculators, introduced in 1973, which had featured scientific notation, squares, square root, and reciprocals, but had no trig or log functions, and lacked other featur