mechanical digital calculator
INTRODUCTION
Electromechanical, mechanical electronic, or electronic devices that automatize mathematical calculations are referred to as calculators. Calculatorsperform calculations using the most basic math functions of addition, subtraction, division, and multiplication. Many are also able to perform more complex calculations, like habitual and inverse trigonometric calculations ( see trigonometry). There are few inventions that have had as profound an influence on our lives like the handheld, or pocket, electronic calculator. These calculators can be used to help save time and reduce the risk of making errors and are used wherever you need to be able to use numbers frequently, in offices, stores, banks and schools, labs, and even in homes.
The earliest calculatorswere mechanical. they computed using components of machines, such as disks, drums, and gears that were powered with a hand crank or later electricity. In the 1950s, many models of mechanical calculators were replaced with electronic calculators that contained integrated circuits, in some cases similar to those found in computers--to accomplish mathematical calculations. Actually, the advanced electronic calculators that we have today are specifically designed, or even special-purpose computers. They come with built-in instructions on how to carry out certain tasks.
Similar to other systems for processing data, calculators are of two kinds: analog and digital. Analog calculators use fluid flow or voltages for instance--and solve math-related problems by constructing an analogy physical to the issue. Clocks, slide rules as well as utility meters, are all examples that are analog calculators. Digital calculators comprise the gadgets most often thought of as calculators. They work directly with numbers or digits , and operate by listing, counting the numbers, comparing and rearranging the digits. The most common digital calculators include cash registers, adding machines as well as desktop or handheld electronic calculators.
PRINCIPLES OF MECHANICAL CALCULATORS
The most fundamental component of mechanical calculators comprises a set of numeral-adding wheels. In a mechanical calculator that is driven by keys (and in many other models) they can be seen through a series of tiny windows that are located on the front of the device. Each wheel is adorned with the numbers from 0 to 9 engraved around the edge. Under each wheel is a column of keys that are marked with the same numbers. Pressing the key 1 in a column turns its numeral wheel by one step; pressing the number 2 key turns the wheel for two steps, and the cycle continues. When the keys 1 and 2 are simultaneously pressed and the wheel moves one step, and then two more, and finally it will indicate the number 3. So a column of numbers can be quickly added by entering the numbers on the keyboard and then reading their totals in the windows. The locking mechanisms that connect the numeral wheels automatically allow for carrying overs. Multiplication is accomplished by repeating addition, while subtraction is performed using indirect methods; and division is accomplished by repeated subtraction.
PRINCIPLES OF ELECTRONIC CALCULATORS
The functions of electronic calculators are carried out by integrated circuits, tiny arrays that comprise thousands or even millions, of transistors. These circuits have permanent instructions for subtraction and subtraction, multiplication and division and (in more sophisticated calculators) additional functions. The numbers that are entered by the user are temporarily stored in addresses, or locations, within the memory known as random-access (RAM) that has room for the numbers entered and generated at any moment when the computer calculates. The numbers that are stored in these addresses are processed by circuits, which contain the instructions for mathematical operations.
HISTORY
The oldest calculator is the abacus. It has been in use for many thousands of years. It is comprised of movable counters that are placed on a marked board or strung across wires. The first version of the slide rule, widely regarded as the first analog calculator that was successful, was invented in 1620 in 1620 by English mathematician Edmund Gunter. It was initially employed to multiply or divide numbers by subtracting or adding their logarithms. Then it was possible to make use of slide rules to calculate square roots, and in certain cases, to calculate trigonometric functions and logarithms.
MECHANICAL CALCULATORS
The first digital mechanical calculator, which was the predecessor to 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 more sophisticated model of the machine that Pascal had designed. It was based on a shaft that had gradually longer teeth that were fixed to the shaft and a cogwheel that had 10 teeth. The cogwheel's edge could be seen on a dial, and was marked with the numbers 0-9. By putting the cogwheel an exact position along the shaft, and then rotating the shaft to rotate it, two numbers could be added. In order to multiply the two numbers the shaft was turned several times. Subtraction was accomplished through turning the shaft in reverse and division was accomplished through repeated subtraction.
In 1878 W.T. Odhner created the pinwheel. When the number was set on a machine that utilized this mechanism, the appropriate number of pins would be elevated on wheels that were carried by the shaft. When the shaft turned, the pins merged with cogwheels, and their movements gave the result to the sum exactly the same way as did the cogwheels in Leibniz's machine. Invention of the pin-wheel made possible to create sleeker and easier to drive machines.
The first key-driven calculator, later dubbed the Comptometer was created by Dorr Eugene Felt in 1886. Key-driven calculators were able to be operated quickly and were frequently employed in offices. In a particular type of calculator that was driven by keys, referred to as key-set machines, the numbers keys were initially depressed, or turned off. A second action, turning a crank or launching an engine--transferred the numbers entered into the keyboard to the wheels for numerals. Key-set was utilized to calculate machines that printed the results onto paper tape since it was impossible to directly drive printers from the keys.
The first successful commercially-produced rotary calculator was invented by Frank S. Baldwin and Jay R. Monroe in 1912. The first rotary calculators included a rotary mechanism to transfer numbers entered on the keyboard to the adding wheel unit. Because the rotary drive lends itself to high-speed repeating subtraction and addition and division, these machines were able to multiply and divide quickly and even automatically.
Mechanical calculators comprise the cash register. It was created in 1879 by James Ritty, a storekeeper to ensure the integrity of his employees. The first bookkeeping machine, an adding-printing device was invented in 1891 in 1891 by William S. Burroughs, an employee of a bank. Punch-card machines, initially used to control the operation of weaving looms, were modified to processing information during the 1880s, by Herman Hollerith of the United States Bureau of the Census. They read data from cards whose patterns of holes were interpreted as numbers and letters.
ELECTRONIC CALCULATORS
The advancements in electronics during the 1940s and 1950s helped make possible the development of computers and the electronic calculator. Electronic desktop calculators were introduced in the 1960s, served the same function as the rotary calculators however they had no moving components. The advent of tiny electronic devices that were solid-state brought about an array of electronic calculators which could perform many more functions and more efficient than their mechanical counterparts. Nowadays, the majority of mechanical calculators are replaced by electronic models.
The latest handheld electronic calculators are able to perform not just multiplication, subtraction, addition and division, but they also can deal with square roots, percentages, and squaring when the appropriate keys are hit. The input data and the result displayed on a display using or light emitting diodes (LEDs) or liquid crystal display (LCDs).
Special-purpose calculators are designed for applications in engineering, business as well as other fields. Certain of them are able to perform a series of tasks similar to the ones performed by larger computers. Advanced electronic calculators can be programmed using complex mathematical formulas. Certain models have interchangeable preprogrammed software modules that can handle up to 5,000 or more steps, but the required data has to be entered manually. A majority of models have built-in printer or an additional one and some are able to graph mathematical equations. A lot of calculators come with basic computer games that are played on the calculator's screen. In actuality, the distinction between calculators and Personal Digital Assistants (PDAs), and portable computers has become blurred since all of these devices are now primarily powered by microprocessors.
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