1)The first
solid state electronic calculator was created in the 1960s, building on the extensive history of tools such as the
abacus, developed around 2000 BC, and the
mechanical calculator, developed in the 17th century. It was developed in parallel with the
analog computers of the day.
2)Pocket sized devices became available in the 1970s, especially after the
invention of the microprocessor developed by
Intel for the Japanese calculator company
Busicom.
Modern electronic calculators vary from cheap, give-away, credit-card
sized models to sturdy desktop models with built-in printers. They
became popular in the mid-1970s as
integrated circuits
made their size and cost small. By the end of that decade, calculator
prices had reduced to a point where a basic calculator was affordable to
most and they became common in schools.
3)Computer operating systems as far back as
early Unix have included interactive calculator programs such as
dc and
hoc, and calculator functions are included in almost all
PDA-type devices (save a few dedicated address book and dictionary devices).
4)In addition to general purpose calculators, there are those designed for specific markets; for example, there are
scientific calculators which include
trigonometric and
statistical calculations. Some calculators even have the ability to do
computer algebra.
Graphing calculators can be used to graph functions defined on the real line, or higher dimensional
Euclidean space.
In 1986, calculators still represented an estimated 41% of the
world's general-purpose hardware capacity to compute information. This
diminished to less than 0.05% by 2007.
[1]
1)Modern electronic calculators contain a
keyboard with
buttons for
digits
and arithmetical operations. Some even contain 00 and 000 buttons to
make large numbers easier to enter. Most basic calculators assign only
one digit or operation on each button. However, in more specific
calculators, a button can perform multi-function working with
key combination or current reckoning mode.
2)Calculators usually have
liquid crystal displays as output in place of historical
vacuum fluorescent displays. See more details in
technical improvements.
Fractions such as
1⁄3 are displayed as decimal
approximations, for example rounded to
0.33333333. Also, some fractions such as
1⁄7 which is
0.14285714285714 (to 14
significant figures) can be difficult to recognize in decimal form; as a result, many scientific calculators are able to work in
vulgar fractions or
mixed numbers.
Calculators also have the ability to store numbers into
memory. Basic types of these store only one number at a time. More specific types are able to store many numbers represented in
variables.
The variables can also be used for constructing formulae. Some models
have the ability to extend memory capacity to store more numbers; the
extended address is referred to as an
array index.
3)Power sources of calculators are batteries, solar cells or
electricity (for old models) turning on with a switch or button. Some
models even have no turn-off button but they provide some way to put
off, for example, leaving no operation for a moment, covering solar cell
exposure, or closing their lid. Crank-powered calculators were also
common in the early computer era.
Las pantallas OLED
tienen todos los números para ser las que dominen el futuro. No solo
mejoran la calidad de imagen, sino que permiten hacer pantallas
flexibles. La evolución en la industria de la televisión en los últimos
años (televisión digital, alta definición, SmartTV, 4K), culmina con la aplicación a los paneles de la tecnología OLED, una tecnología que aúna lo mejor de las que ahora imperan, LED/LCD y plasma, que puede acabar, cuando se estandarice, con la dicotomía ahora imperante.
