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Peripherals Peripheral types We can classify peripherals into: input units, output units and auxiliary mass memory units. Input devices The input devices are those that allow information to be entered into the computer, the most important of which are: Keyboard

It is a device similar to that of a typewriter, in which each key corresponds to one or more characters, functions or commands. To select one of the characters on a key, it may be necessary to press two or more keys simultaneously. Among the technical characteristics of a keyboard are the number of basic characters and symbols, the sensitivity to the touch, the type of key contacts (membrane or mechanical), weight, size, portability, ergonomics, extra functionalities such as magnetic stripe reader , smart card reader and writer, etc). The interface between the keyboard and the computer can be wired or wireless using infrared or radio frequency signals. For us, together with the mouse, one of the most important peripherals. Mouse or mouse

The original mouse consisted of a ball that could rotate freely and was driven by rolling it on a flat surface. The current ones have replaced the ball with an optical system of diode or infrared laser. Activating the mouse associates its position with that of the cursor on the screen, making it follow the movements of the mouse as it moves over a surface. The concept of the mouse has been expanded with the introduction of other analog devices such as the trackball that consists of a fixed ball that is rotated with the fingers, the touchpad, which uses a panel sensitive to the gentle pressure of the fingers or the pointing stick. , a small vertical cylinder. They are all used in laptop keyboards and use connection interfaces analogous to keyboards. Optical pencil The stylus is one of the most modern peripherals, at least in the home use sector. It is a device associated with touch screens, when activating the stylus in front of a point on the screen, the coordinates of the place where the stylus was pointing are obtained.Touch or touch sensitive screen

They are screens that can detect the coordinates of the area of ​​the screen that is touched with a pointer. This type of screens can be capacitive or resistive depending on whether or not they need electrical conductivity in the pointer to work.

Digitizer
These devices allow a digital representation of graphics, figures, plans, maps, or drawings in general to be transferred to the computer. This is achieved by manually sliding a moving part over the line to be digitized, which transfers the coordinates of the points that make up the image.

Reading devices

These are alternatives to the keyboard that are used when it is necessary to provide a large amount of information to the computer quickly and reducing the risk of errors. Among the most common we find the following.

Scanner
These are devices that allow the tracking of images or printed documents, which are processed with an optical character recognition (OCR) program and the original text is generated in the most common text editors format.

Magnetic Stripe Detector
It uses electromagnetic signals to record and encode information on a magnetic strip, which can be read by a machine. They are present in a large number of objects of everyday life such as credit cards, health cards, airline tickets and many more.

Smart card reader
Smart cards are similar in dimensions to credit cards, but they incorporate an electronic circuit and a small memory capable of storing much more data than a magnetic strip.Brand and barcode readers

Allows you to read barcodes or predefined marks. They are the typical readers that we can find in all supermarkets in the checkout section.

Sensors
Sensors are electronic devices created to capture measurements of physical properties, such as temperature, pressure, humidity, etc. They are widely used in industry, laboratories, medical instrumentation and meteorology. Among them, biometric systems stand out, used for access control and security applications, these use information about some physiological characteristic as a means of personal identification.

Output devices


The output devices serve as a one-way window from the computer to the user.

Monitor or screen
A screen is a white, flat and smooth surface, made of textile or plastic, onto which cinematographic or photographic images are projected. Various technologies and features are used, among which the following stand out:

Cathode ray tube (CRT).
Liquid crystal (LCD: Liquid Crystal Display).
Plasma.
OLED.
All of them have in common that the image is not continuous, but is formed by a multitude of image points called pixels. These pixels are grouped into a regular array of image dots. The resolution of a screen is the number of image points that a screen has, it is a value independent of its size. Another of the key peripherals when choosing a good computer.

Printer
The screens show the results temporarily, so we need to have a printing system if we want to have a permanent copy of the data. Printers can be classified based on some of their characteristics:

Depending on the print quality:

Normal: line, wheel and thermal printers.
Medium quality - some dot matrix printers.
High quality: those of daisy, ink and laser.

According to the printing system:

Impact printers. Traditionally widely used, but they are noisy so they are no longer in use. These include wheel, ball, daisy, dot matrix, cylinder and chain printers.
Non-impact printers. they form the characters without the need for strokes and use other physical principles to transfer the images to paper. They are the ones used today, including inkjet, electrostatic, LED and laser.
Inkjet printers. They are character printers and their problem is relative slowness.
Electrostatic printers. They are very fast line printers.
Laser printers. They are widely used for their high speed, print quality, relatively low price and being able to use plain paper.
LED printers. They are analogous to lasers, with the only difference that the image is generated from a row of diodes, instead of a laser.
All printers are characterized by a series of parameters, the most important of which are the following:

Write speed.
Characters per line.
Paper width or carriage length in inches.
Density of lines per inch and space between them.
Fonts that the printer can use.
Color or grayscale.
Resolution.
Printers are one of the most used peripherals at the office and home level.

Wireless or wired peripherals


A first question that may arise when purchasing a new peripheral is whether we opt for a wireless model or a wired one. A priori, a peripheral without cable is more comfortable since we will not have the problem of entanglements with cables and we will enjoy greater freedom of movement.

But not everything is pink in wireless technology, these types of peripherals are more prone to interference, their autonomy is limited due to the limited capacity of the battery or batteries, and communication with the PC has more delay. , what we call latency. During the last few years, all these problems have been minimized and we can already find mice and keyboards that last for a year and a half with two or three batteries, have a latency equal to a wired model and do not suffer interference.