calculators
INTRODUCTION
Electronic, electromechanical electronic or electromechanical devices that do mathematical calculations automatically are referred to as calculators. Calculatorsperform functions that perform the most basic arithmetic functions--addition, subtraction, division and multiplication. Some can also do more complicated calculations, such as cotidiano and inverse trigonometric operations ( see trigonometry). Few inventions of recent times have had such an impact influence on daily life such as the handheld, or pocket, electronic calculator. These calculators are used to save time and to reduce the chance of making mistakes and are found wherever you need to be able to use numbers frequently, in offices, stores, banks, schools, laboratories, as well as in private homes.
The early calculatorswere mechanical. they ran their calculations with components of machines, such as disks, drums, and gears--that were powered via hand, and later electricity. In the 1950s, many were mechanical calculators were replaced with electronic calculators which were equipped with integrated circuits -- in some cases similar those found in computers--to perform mathematical functions. In actuality, the high-end electronic calculators of today are specially-purpose computers. They have built-in instructions for how to perform certain limited functions.
As with other computing systems, calculators are of two kinds--digital and analog. Analog calculators utilize different physical quantities, such as fluid flow or voltages, as an example. They solve mathematical problems through the creation of an analogy in physical form to the problem. Slide rules, clocks or utility meters are all examples that are analog calculators. Digital calculators comprise the gadgets most frequently thought of as calculators. They directly deal with the numbers or digits. They function by listing, counting as well as comparing these numbers. The most common digital calculators include cash registers, adding machines and desktop or handheld electronic calculators.
PRINCIPLES OF MECHANICAL CALCULATORS
The primary component of mechanical calculators is a set numeral-adding wheels. In a key-driven mechanical calculator (and in many other models) these may be seen through a row of small window on the side on the front of your machine. Each wheel has the numerals in the range 0-9, which are engraved on its rim. Beneath each wheel is a column of keys marked with the same digits. The number 1 key in a column spins the numeral wheel one step. depressing the key number 2 turns the wheel 2 steps and so on. When the keys 1 and 2 are pressed in succession it will move the wheel one step, and then two moretimes, before finally showing the number 3. This means that a column can be quickly added by entering the numbers in the keyboard and observing their sum in the window. Mechanisms that lock the numeral wheels automatically allow for carrying overs. Multiplication is done by repeated addition. Subtraction is achieved through indirect methods and division is accomplished by repeated subtraction.
PRINCIPLES OF ELECTRONIC CALCULATORS
Electronic calculators are accomplished by integrated circuits - tiny arrays of tens with thousands or even millions, of transistors. These circuits include permanent instructions for addition to, subtraction, multiplication, division as well as (in more sophisticated calculators) additional functions. The numbers input by the operator will be briefly stored in addresses, or locations, in the memory known as random-access (RAM) that has space for the numbers used and produced at any given time through the computer. The numbers that are stored in these addresses are then processed by the circuits that carry the instructions to perform the mathematical operations.
HISTORY
The most ancient calculating aid is the abacus. It was used for many thousands of years. It is comprised of movable counters, which are either placed on a marked board or strung across wires. The first version of the slide rule, widely regarded as the first digital calculator that worked, was developed in 1620 through the English mathematician Edmund Gunter. The slide rule was originally utilized to multiply or divide numbers by subtracting or adding their logarithms. Later , it was possible make use of slide rules to calculate square roots, and in certain instances, to calculate trigonometric functions and logarithms.
MECHANICAL CALCULATORS
The first digital mechanical calculating machine--the predecessor of 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 higher-tech variant of Pascal's device. It had a shaft fitted with increasing length of teeth, which were fixed to the shaft, and a cogwheel with 10 teeth. The edges of the cogwheel displayed on a dial and was marked with numbers 0-9. By placing the cogwheel an exact position along the shaft, and then turning the shaft and then turning it again, two numbers could be added. For the purpose of multiplying two numbers it was necessary to rotate the shaft several times. Subtraction was made via turning the shaft in reverse and division took place with subtraction that was repeated.
In 1878 W.T. Odhner invented the pin-wheel. When a number was set on a machine that utilized this mechanism, the appropriate number of pins were raised by wheels on the primary shaft. When the shaft was turned, the pins were locked with cogwheels, whose revolutions gave the answer to the sum in the same manner as were the cogwheels used in Leibniz's invention. With the invention of the pin-wheel has made it possible to make simpler and more efficient machines.
The first successful commercially-produced key-driven calculatorthat was later named the Comptometer was developed by Dorr Eugene Felt in 1886. Key-driven calculators were able to be operated quickly and were commonly employed in offices. In one kind of key-driven calculator, called a key-set device, the numbers keys were initially depressed or cocked. A second action, turning a crank or starting a drive motor--transferred the number set into the keyboard to the wheels for numerals. Key-set principles were used in calculating machines that printed their results on paper tape since it was impossible to drive printers directly from the keys.
The first successful commercially-produced circular calculator was designed by Frank S. Baldwin and Jay R. Monroe in 1912. Rotary calculators had a rotary motor to transfer numbers that were set on the keyboard onto the adding-wheel unit. Because the rotary drive lends itself to high-speed repetition of subtraction and addition, these machines could increase and decrease quickly, and even automatically.
The special-purpose calculators consist of the cash register, which was invented in 1879 James Ritty, a storekeeper to ensure the honest conduct of his staff. The first bookkeeping equipment--a printing-addition device -- was created in 1891, through William S. Burroughs, the bank clerk. Punch-card machinesthat were originally designed to control the operation of weaving machines, were made to adapt to processing information during the 1880s, by Herman Hollerith of the United States Bureau of the Census. They read information from cards whose patterns of holes represented numbers as well as letters.
ELECTRONIC CALCULATORS
Advancements in electronics in the 1940s and 1950s made possible the invention of computers and the electronic calculator. Electronic desktop calculators which were introduced in 1960s, were able to perform the same functions as mechanical calculators but had virtually no moving components. The development of miniature electronic devices that used solid state technology brought an array of electronic calculators which could perform significantly more functions and quicker operation than their mechanical counterparts. Nowadays, the majority of mechanical calculators have been replaced by electronic models.
Contemporary handheld electronic calculators can do not only multiplication, subtraction and division but can handle square roots percentages, and squaring. These are all possible when the appropriate keys are activated. The data that is entered and the result are displayed on a display using LEDs or either (LEDs) or liquid crystal displays (LCDs).
Special-purpose calculators have been developed for applications in engineering, business as well as other fields. Some of them are equipped to carry out a sequence of tasks that are similar to the ones performed by larger computers. Highly sophisticated electronic calculators can be programmed with complicated mathematical formulas. Certain models come with interchangeable software modules that can handle 5 or more program steps, but the required information must be entered manually. Many units have a built-in or accessory printer with graphing capabilities, while some models can draw mathematical equations. Many calculators offer basic computer games that can be played on the calculator's screen. The distinction between calculators, portable digital assistants (PDAs) and portable computers is blurred because all these devices are now primarily powered by microprocessors.
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