Discover best deals on many top brands home electronics only available on eBay!

Calculators

A calculator is a device for performing calculations. Although modern calculators often incorporate a general purpose computer, the device as a whole is designed for ease of use to perform specific operations, rather than for flexibility. more...

Home

Amplifiers

Audio Accessories & Cables

Cable TV

DVD Players & Recorders

Digital Video Recorders, PVR

Gadgets & Other Electronics

Financial Calculators

Sharp

Casio

Scientific Calculators

Hewlett-Packard

Other

Texas Instruments

Vintage Calculators

Clocks

Dictionaries & Translators

eBooks

Flashlight Key Chains

Timers

WebTV

Home Theater Projectors

Home Theater in a Box

Radios: CB, Ham & Shortwave

VCRs

Vintage Electronics

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 abacuses, 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 soon 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.

A basic calculator

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; 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 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.;

Since the late-1980s, simple calculators have been installed in other small devices, such as mobile phones, pagers or wrist watches.

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 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 will simply display "error". It is very difficult to store the memory necessary to calculate larger numbers in so small an instrument.