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The Fuller calculator, sometimes called Fuller's cylindrical slide rule, is a cylindrical slide rule with a helical main scale taking 50 turns around the cylinder. This creates an instrument of considerable precision – it is equivalent to a traditional slide rule 25.40 metres (1,000 inches) long.
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 ...
While the above example lies within one decade, users must mentally account for additional zeroes when dealing with multiple decades. For example, the answer to 7×2=14 is found by first positioning the top scale to start above the 2 of the bottom scale, and then reading the marking 1.4 off the bottom two-decade scale where 7 is on the top scale:
The 1/4-turn shaft carries (also, each column) gears with 12, 16, and 20 teeth, for 3, 4, and 5. Digits [1] and [2] are handled by 12 and 24-tooth gears on the 1/12-revolution shaft. Practical design places the 12th-rev. shaft more distant, so the 1/4-turn shaft carries freely-rotating 24 and 12-tooth idler gears.
The first American-made pocket-sized calculator, the Bowmar 901B (popularly termed The Bowmar Brain), measuring 5.2 by 3.0 by 1.5 inches (132 mm × 76 mm × 38 mm), came out in the Autumn of 1971, with four functions and an eight-digit red LED display, for US$240, while in August 1972 the four-function Sinclair Executive became the first ...
Following the patent and release of Harold's Long Scale calculator featuring two knobs on the outside rim in 1914, he designed the Magnum Long Scale calculator in 1927. [6] [7] As the name "Magnum" implies, it was a fairly large device at 4.5 inches in diameter—about 1.5 inches more than Fowler's average non-Magnum-series calculators. [8]
A scale ruler is a tool for measuring lengths and transferring measurements at a fixed ratio of length; two common examples are an architect's scale and engineer's scale.In scientific and engineering terminology, a device to measure linear distance and create proportional linear measurements is called a scale.
A partially disassembled Curta calculator, showing the digit slides and the stepped drum behind them Curta Type I calculator, top view Curta Type I calculator, bottom view. The Curta is a hand-held mechanical calculator designed by Curt Herzstark. [1] It is known for its extremely compact design: a small cylinder that fits in the palm of the hand.