calculators
INTRODUCTION
Electromechanical, mechanical electronic, or electronic devices that can perform math-related calculations automatically are called calculators. Calculators perform calculations using the most basic Arithmetic functions, including subtraction, multiplicationand division. They are also capable of performing more complex calculations, such as genérico and inverse trigonometric calculations ( see trigonometry). A few technological advances of recent times are having such a significant influence on the daily routine such as the handheld, or pocket electronic calculator. These calculators are used to cut down on time and to reduce the chance of making mistakes and are available everywhere that people are often in offices, retail stores, banks as well as in laboratories, schools and even in homes.
The first calculators were mechanical: they ran their calculations with machine components, like disks, gears, and drums. They were powered with a hand crank or later electricity. By the mid-1950s many machines such as these calculators were replaced by electronic calculators which had integrated circuits--in some cases like the ones found in computers to provide mathematical functions. In actuality, the high-end electronic calculators of today are purpose-built, or special-purpose computers. They include built-in instruction on how to carry out certain operations.
Like other data-processing systems, calculators are of two types: digital and analog. Analog calculators operate with variable physical quantities--fluid flow or voltages for instance. They also solve math-related problems by constructing physical analogies to the issue. Clocksand slide rules and utilities meters can be examples that are analog calculators. Digital calculators include the devices most often thought of as calculators. They are directly based on the numbers or digits. They function by listing, counting or listing, comparing, and changing the arrangement of these digits. The most common digital calculators include adding machines, cash registers as well as handheld or desktop electronic calculators.
PRINCIPLES OF MECHANICAL CALCULATORS
The most fundamental component of mechanical calculators includes a set numeral-adding wheels. In a mechanical calculator that is driven by keys (and for the vast majority of other types of calculators) these may be seen through the rows of small windows at the top part of the instrument. Each wheel is adorned with the numbers of 0 through 9 around its rim. Behind each wheel, there is a column of keys marked with the same numbers. Pressing the key 1 in a column spins the numeral wheel one step; pressing the number 2 key turns the wheel by two steps and then on. When the 1 and 2 keys are simultaneously pressed then the wheel will advance one step and then two more, and finally it will indicate the number 3. A column of numbers could be quickly added by typing the numbers on the keyboard and observing their sum in the windows. The locking mechanisms that connect the numeral wheels automatically ensure carryovers. Multiplication is achieved by repeated addition; subtraction is done by an indirect method; and division is accomplished by repeated subtraction.
PRINCIPLES OF ELECTRONIC CALCULATORS
Electronic calculators are carried out by integrated circuits -- tiny arrays made up comprising thousands, and millions of transistors. These circuits are equipped with permanent instructions for subtraction or subtraction, multiplication or division and (in more advanced calculators) other functions. The numbers entered by the operator are briefly stored in addresses or locations in the memory called random-access (RAM), which has space for the numbers used and created at any time when the computer calculates. The numbers stored in these addresses are then processed by circuits that hold the instructions for the mathematical operations.
HISTORY
The oldest tool for calculating is the abacus. It has been in use for a number of thousands of years. It is comprised of movable counters that are placed on a marked board or strung along wires. A first variant of the slide rule, widely regarded as the first analog calculator that was successful, was designed in 1620 in 1620 by English mathematician Edmund Gunter. A slide rule originally used to multiply or divide numbers by adding or subtracting their logarithms. Later , it was possible utilize slide rules to determine square roots, and in some cases, to calculate trigonometric operations and logarithms.
MECHANICAL CALCULATORS
The first mechanical digital calculating machine, the precursor to the modern calculator, was an arithmetic machine designed by French mathematician Blaise Pascal in 1642 ( see Pascaline). Later in the 17th century Gottfried Wilhelm Leibniz created a more sophisticated design of Pascal's invention. It was based on a shaft that had more and longer teeth fixed on the shaft and a cogwheel that had 10 teeth. The cogwheel's edges could be seen on a dial, and was marked with numbers 0-9. The cogwheel was placed in a particular direction on the shaft, and then rotating the shaft to rotate it, two numbers could be added. When multiplying two figures using the cogwheel, the shaft was turned repeatedly. Subtraction was achieved using the shaft turned backward, and division was performed with subtraction that was repeated.
In 1878 W.T. Odhner came up with the idea of the pin wheel. When a number was determined on a machine with this mechanism, the appropriate number of pins would be elevated on wheels that were carried by the main shaft. When the shaft was turned, the pins were locked with cogwheels, whose revolutions gave the answer to the equation in the same manner as did those of Leibniz's device. It was the development of the pin wheel made it possible to create sleeker and easier to drive machines.
The first successful commercially-produced key-driven calculator, later called the Comptometer was invented by Dorr Eugene Felt in 1886. Key-driven calculators were able to be operated swiftly and were extensively employed in offices. In one kind of key-driven calculator, known as key-set machines, the number keys were first pressed or they were cocked. After that, turning a crank or turning on an engine--transferred the numbers entered into the keyboard to the wheels for numerals. Key-set was utilized to calculate machines that printed outputs on paper tape because it was not possible to directly drive printers from the keys.
The first commercially successful computer was designed by Frank S. Baldwin and Jay R. Monroe in 1912. The first rotary calculators featured a rotary mechanism that transferred numbers from the keyboard to the adding-wheel unit. Since the rotary drive lent itself to high-speed repetitive addition and subtraction the machines were able to multiply and divide rapidly and in a controlled manner.
Mechanical calculators include the cash register, which was developed in 1879 by James Ritty, a storekeeper, to ensure the honesty of his clerks. The first bookkeeping machine - an adding-printing device was invented in 1891 from William S. Burroughs, a bank clerk. Punch-card devices, originally utilized to regulate the operation weaving machines, were made to adapt to information processing early in 1880s. Herman Hollerith of the United States Bureau of the Census. They read data from the cards, and patterns of holes symbolized numbers and letters.
ELECTRONIC CALCULATORS
Advancements in electronics in the 1940s, 1950s, and 1960s made possible the development of computers and the electronic calculator. Electronic desktop calculators which were introduced in 1960s, had the similar functions to rotating calculators but they were without moving components. The advent of tiny electronic devices that used solid state technology brought a series of electronic calculators that were capable of many more functions and more speed than their mechanical counterparts. Today , the majority of mechanical calculators have been replaced with electronic models.
Modern handheld electronic calculators can perform not only subtraction, multiplication and division but are able to handle square roots percentages, and squaring. These are all possible whenever the appropriate button is hit. The data that is entered and the final result are displayed on a screen using LEDs or either (LEDs) or liquid-crystal screens (LCDs).
Special-purpose calculators are designed for use in engineering, business as well as in other fields. Some are able to perform a series of tasks much like the work of larger computers. Sophisticated electronic calculators are able to be programmed using complex mathematical formulas. Some models employ interchangeable preprogrammed software modules that are capable of thousands or more of program steps, but the required data has to be entered manually. There are many calculators that have a built-in printer or an additional one with graphing capabilities, while some models can draw mathematical equations. A lot of calculators come with basic computer games that are played directly on the calculator's screen. The distinction between calculators and portable digital assistants (PDAs), and portable computers is blurred because all of these devices are now primarily powered by microprocessors.
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