|
Calculators
A calculator is a hand-held device for performing calculations. Although modern calculators often incorporate a general purpose computer, the device is designed for performing specific operations, rather than for flexibility. more...
 Home
A/V Accessories & Cables
Apple iPod, MP3 Players
DVD & Home Theater
Gadgets & Other Electronics
 Air Purifiers
Breathalyzers
Calculators
 Basic Calculators
Books, Manuals
Financial Calculators
 Hewlett-Packard
Other Brands
Sharp
Texas Instruments
Graphing Calculators
Cables, Links
Hewlett-Packard
Other Brands
Texas Instruments
Other Calculators
Printing Calculators
Scientific Calculators
Hewlett-Packard
Other
Texas Instruments
Vintage Calculators
Dictionaries & Translators
Digital Clocks & Clock...
eBooks
Flashlight Key Chains
Fresnel Lenses
Home Automation
Language Filters
Laser Pointers
Metal Detectors
Other Gadgets
Polygraphs
Radiation Detectors
RF Locators
Surveillance
Therapeutic Devices
Timers
Voltage Converters
Weather Devices
Home Audio
MP3 Accessories
Portable Audio/Video
Radios: CB, Ham & Shortwave
Satellite Radio
Satellite, Cable TV
Telephones & Pagers
Televisions
For example, there are graphing calculators which focus on graph-centered math like trigonometry and statistics. Also, modern calculators are more portable than most computers, though some PDAs are comparable in size to handheld calculators.
Overview
In the past, mechanical clerical aids such as abaci, comptometers, Napier's bones, books of mathematical tables, slide rules, or mechanical adding machines were used for numeric work. The word "calculator" denoted a person who did such work for a living using such aids as well as pen and paper. This semi-manual process of calculation was tedious and error-prone.
Modern calculators are electrically powered and come in countless shapes and sizes varying from cheap, give-away, credit-card sized models to more sturdy adding machine-like models with built-in printers.
Electronic calculators
In the past, some calculators were as large as today's computers. The first mechanical calculators were mechanical desktop devices which were replaced by electromechanical desktop calculators, and then by electronic devices using first thermionic valves, then transistors, then hard-wired integrated circuit logic. Today, most calculators are handheld microelectronic devices.
Basic configuration
The complexity of calculators varies with the intended purpose. A simple modern calculator might consist of the following parts:
A power source, such as a battery or a solar panel or both;
A display, usually made from LED lights or liquid crystal (LCD), capable of showing a number of digits (typically 8 or 10);
Electronic circuitry;
A keypad containing:
The ten digits, 0 through 9;
The decimal point;
The equals sign, to prompt for the answer;
The four arithmetic functions (namely, addition, subtraction, multiplication and division);
A Cancel (or clear) button, to clear the current calculation;
On and off buttons;
Other basic functions, such as square root and percentage (%).;
;
More advanced models may have a single-number memory, which can be recalled where necessary. It might also have a Cancel Entry button, to clear the current numbers being entered.;
Since the late-1980s, simple calculators have been installed in other small devices, such as mobile phones, pagers or wrist watches. The wristwatch calculator was made popular by Dr. James Buccanon, president of the University of Pennsylvania.
Advanced electronic calculators
More complex scientific calculators support trigonometric, statistical and other mathematical functions. The most advanced modern calculators can display graphics, and include features of computer algebra systems. They are also programmable; calculator applications include algebraic equation solvers, financial models and even games. Most calculators of this type can print numbers up to ten digits or decimal places in full on the screen. Scientific notation is used to notate numbers up to a limit chosen by the calculator designer, such as 9.999999999*1099. If a larger number or a mathematical expression yielding a larger number than this is entered (a common example comes from typing "100!", read as "100 factorial") then the calculator might simply display "error".
Read more at Wikipedia.org
|
|
Contact
