calculators
INTRODUCTION
Electromechanical, mechanical electronic, or electronic devices that automatize mathematical calculations are referred to as calculators. Calculators perform the most basic Arithmetic operations--subtraction, addition multiplicationand division. They can also perform more complex calculations, such as trivial and inverse trigonometric calculations ( see trigonometry). A few technological advances of recent times have had such an impact influence on our lives such as the handheld, or pocket, electronic calculator. These calculators are utilized to save time as well as reduce the likelihood of making mistakes and are found wherever there are people who frequently deal with numbers - in offices, stores, banks, schools, laboratories, and even in homes.
The earliest calculators were mechanical. they carried out calculations using mechanical components such as disks gears, drums and drums. They were powered either by hand or later electricity. By the mid-1950s many of these mechanical calculators were being replaced by electronic calculators which had integrated circuits -- in some cases similar the ones found in computers to provide mathematical functions. In actuality, the high-end electronic calculators that we have today are specially-purpose computers. They include built-in instruction on how to use certain tasks.
Similar to other systems for processing data, calculators are of two types--analog and digital. Analog calculators work with variable physical quantities--fluid flow or voltages, as an example. They solve math-related problems by constructing physical analogies to the problem. Slide rules, clocks and utilities meters can be examples that are analog calculators. Digital calculators comprise the gadgets most commonly thought of as calculators. They work directly with the numbers or digits. They function by counting, listing the numbers, comparing and rearranging the numbers. Digital calculators include cash registers, adding machines, and handheld or desktop electronic calculators.
PRINCIPLES OF MECHANICAL CALCULATORS
The basic part of most mechanical calculators are a set numeral-adding wheels. In a key-driven mechanical computer (and in most others) these may be seen through a series of tiny window on the side of the device. Each wheel is adorned with the numbers in the range 0-9, which are engraved on its edges. Beneath each wheel is a column of keys that are marked with the same numerals. Depressing the number 1 key in a column spins the numeral wheel one step, depressing the number 2 key rotates the wheel twice; and so on. When the 1 and 2 keys are simultaneously pressed and the wheel moves one step forward, then two moretimes, before finally showing 3. So a column of numbers may be added rapidly by simply typing in the numbers on the keyboard and seeing their sum in the window. Interlocking mechanisms between the numeral wheels automatically enable carryovers. Multiplication is performed by repeated addition, while subtraction is performed using indirect methods; the division process is carried out by repeated subtraction.
PRINCIPLES OF ELECTRONIC CALCULATORS
The functions of electronic calculators are performed by integrated circuits--tiny arrays comprising thousands, and even millions of transistors. These circuits have permanent instructions for subtraction and subtraction, multiplication and division as well as (in more advanced calculators) other functions. The numbers input by the operator will be briefly stored in addresses or locations, inside the random-access memory (RAM) that has enough space to store the numbers that are used and produced at any given time by the calculator. The numbers stored in these locations are processed by circuits that contain the instructions for the mathematical operations.
HISTORY
The oldest calculator is the abacus, which was used for hundreds of years. It's composed of movable, counters that were placed on a marking board or strung on wires. A first variant of the slide rule widely regarded as the first successful analog calculator, was invented in 1620, by the English mathematician Edmund Gunter. A slide rule originally employed to multiply and divide numbers by subtracting or adding their logarithms. In the future, it was possible to make use of slide rules to calculate square roots as well as, in certain instances, to calculate trigonometric functions and logarithms.
MECHANICAL CALCULATORS
The first mechanical digital calculating machine -- the forerunner of the modern calculator -- was an arithmetic machine invented by French mathematician Blaise Pascal in 1642 ( see Pascaline). In the 17th century Gottfried Wilhelm Leibniz created a higher-tech variant of Pascal's device. It utilized a shaft with more and longer teeth fixed on the shaft and a cogwheel that had 10 teeth. The cogwheel's edges showed in a dial and was marked with the numbers 0 to 9. The cogwheel was placed in a particular direction on the shaft, and then rotating the shaft and then turning it again, two numbers could be added. In order to multiply the two numbers the shaft was turned repeatedly. Subtraction was achieved using the shaft turned backward and division was achieved through repeated subtraction.
In 1878 W.T. Odhner developed the pin-wheel. When the number was set on a machine with this device, the number of pins would be raised on wheels carried on the main shaft. When the shaft turned, the pins were locked with cogwheels, whose rotations gave the answer to the equation similar to how they did those on Leibniz's machines. With the invention of the pin-wheel was what made it possible to make simpler and more efficient machines.
The first successful commercially-produced key-driven calculatorlater known as the Comptometer was developed by Dorr Eugene Felt in 1886. Key-driven calculators were able to be operated quickly and were commonly used in offices. In a certain type of key-driven calculator, called a key-set machine, the keypads for numbers were first depressed or cocked. Then a second action--turning a crank or the start of with a drive motor, transferred the number entered into the keyboard to the wheels for numerals. Key-set principles were used for calculating machines that printed out results on paper tape as it was impossible to direct printers directly from the keys.
The first commercially successful Rotary calculator was created by Frank S. Baldwin and Jay R. Monroe in 1912. The first rotary calculators featured a rotary mechanism to transfer numbers entered on your keyboard to the add-wheel unit. Because the rotary drive lends itself to high-speed repetitive subtraction and addition that these machines could be able to multiply and divide extremely quickly and even automatically.
Mechanical calculators include the cash register. This was invented in 1879 , by James Ritty, a storekeeper in order to guarantee the honesty of his employees. The first bookkeeping device--an adding printing device--was invented in 1891 in 1891 by William S. Burroughs, one of the bank's clerks. Punch-card machinesoriginally employed to control the operation of weaving looms, were modified to information processing around the time of the 1800s. They were developed by Herman Hollerith of the United States Bureau of the Census. They read information from cards whose patterns of holes were interpreted as numbers and letters.
ELECTRONIC CALCULATORS
Electronics advancements during the 1940s and 1950s led to possible the invention of computers and the electronic calculator. Electronic desktop calculators which were introduced in 1960s, fulfilled the same functions as mechanical calculators but were essentially without moving parts. The development of miniature electronic devices that were solid-state brought about the world a variety of electronic calculators that could carry out many more functions and quicker operation than their mechanical predecessors. Nowadays, the majority of mechanical calculators are replaced by electronic models.
The latest handheld electronic calculators are capable of not only addition, subtraction, multiplication and division, but can handle square roots, percentages, and squaring. This is when the correct key is press. The data that is entered and the result displayed on a display using or light emitting diodes (LEDs) or liquid crystal display (LCDs).
Special-purpose calculators have been designed to use in business, engineering and other areas. Certain of them are able to carry out a sequence of operations similar to those handled by larger machines. Electronic calculators can be programmed using complicated mathematical formulas. Certain models use interchangeable preprogrammed software modules that are capable of thousands or more of program steps, though the necessary data must still be keyed manually. There are many calculators that have a built-in printer or an additional one as well as some that can graph mathematical equations. A lot of calculators include rudimentary computer games that can be played on the calculator's screen. In actuality, the distinction between calculators and portable digital assistants (PDAs) and portable computers is blurred due to the fact that all of these devices now typically use microprocessors.
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