Basic peripheral devices. Basic computer peripherals

Peripherals– these are any additional and auxiliary devices that are connected to a PC to expand its functionality.

Input devices

(keyboard, mouse, trackball, joystick, scanner, microphone, etc.)

Trackball (trackball)- this is a ball located along with the buttons on the surface of the keyboard (an inverted mouse).

The pointer moves around the screen by rotating the ball.

Touch manipulator. It is a mousepad without a mouse. In this case, the cursor is controlled by simply moving your finger across the mat.

Digitizer (graphics tablet) Allows you to create or copy drawings. The drawing is made on the surface of the digitizer with a special pen or finger. The results of the work are displayed on the monitor screen.

Scanner- a device for entering information into a computer from paper. Scanners come in flatbed, desktop and handheld types.

Mouse- information input device. Converts mechanical movements on the table into an electrical signal transmitted to the computer.

Light pen- with it you can draw pictures and write handwritten texts that immediately appear on the screen.

Output devices

(monitor, printer, plotter, speakers, etc.)

Monitor- the main peripheral device for displaying information visible to a computer.

Modem- a device for connecting computers to each other over long distances via a telephone line. Using a modem you can connect to the Internet.

Printer- a device for displaying information on paper. Printers can be matrix (ink ribbon), inkjet (ink cartridge), laser (cartridge with toner powder).

Microphone-audio information input device: voice or music.

Plotter, or plotter, is a drawing machine that allows you to draw complex large-sized graphic images with high accuracy and speed: drawings, diagrams, maps, graphs, etc.

14. Computer memory - types, types, purpose.

Computer memory provides support for one of the most important functions of a modern computer - the ability to store information for a long time

Computer memory is one of the most important issues in computer design, as it provides support for one of the most important functions of a modern computer - the ability to store information for a long time.

One of the main elements of a computer that allows it to function normally is memory.

All personal computers use three types of memory: RAM, permanent memory and external (various storage devices).

The internal memory of a computer is where the information it works with is stored. External memory (various drives) is designed for long-term storage of information

The most familiar means of machine data storage used in personal computers are: RAM modules, hard drives (hard drives), floppy disks (floppy disks), CDs or DVDs, and flash memory devices.

There are two types of computer memory: internal and external. Internal memory: random access memory (RAM) and read only memory (ROM). The most essential part internal memory is called RAM- random access memory device. Its main purpose is to store data and programs for currently being solved problems. RAM. This memory is called "RAM" because it works very quickly, so that the processor practically does not have to wait when reading data from memory or writing to memory. However, the data it contains is only saved while the computer is turned on.

Read Only Memory (ROM)), which, in particular, stores information necessary for the initial boot of the computer when the power is turned on. As the name suggests, the information in ROM does not depend on the state of the computer.

External memory is usually located outside the central part of the computer

External memory includes various magnetic media (tapes, disks), optical disks. External memory is cheaper than internal memory, but its disadvantage is that it is slower than internal memory devices.

There are CD-ROM discs - write-once discs; they cannot be erased or rewritten.

Later, rewritable laser discs were invented - CD-RW.

External memory It is implemented in the form of quite a variety of information storage devices and is usually structurally designed in the form of independent blocks. This, first of all, should include drives on floppy and hard magnetic disks (users often call the latter somewhat jargonously hard drives), as well as optical drives (devices for working with CD ROMs).

Types of personal computer memory

Cache memory. The main purpose of cache memory in a computer is to serve as a temporary storage place for program codes and data currently being processed. That is, its purpose is to serve as a buffer between various devices for storing and processing information

BIOS (read-only memory). The computer also has permanent memory into which data is stored during manufacture. As a rule, this data cannot be changed; programs running on the computer can only read it.

The computer stores programs in permanent memory to test the computer's hardware, initiate OS loading, and perform basic functions for servicing the computer's devices. Often the contents of permanent memory are called BIOS. It contains the computer configuration program (SETIR), which allows you to set some characteristics of the computer devices (types of video controller, hard drives and floppy drives and I/O services.

CMOS (semi-permanent memory).

a small area of memory for storing computer configuration settings. It is often called CMOS memory because this memory is typically a low-power technology.

Video memory.

video memory, that is, memory used to store the image displayed on the monitor screen.

and permanent memory (ROM).

Computer memory is divided into external (main): floppy and hard drives, CDDVD-ROM, CD DVD-RW, CD DVD-R and internal.

Peripheral devices include: printers, scanners, speakers, modems, i.e. those devices without which the computer can function independently.

Printers. Printers (print - printing) are automatic printing devices designed for printing the results of work on a computer (texts, drawings, graphs) onto paper. Based on the principle of operation, impact-matrix, inkjet and laser printers are distinguished.

Impact matrix printers print using a head with a set of needles. The number of needles in the head can be different - 9, 18 and 24. The movements of the needles, head and sheet are controlled by the electronic circuit of the printer in accordance with commands coming from the computer. At the command of the computer, the needles are assembled into groups corresponding to the outlines of the letters, and, moving out of the head, beat out the desired symbols through the ink ribbon. The more needles in the head, the higher the print quality. Printing speed is from 60 to 10 seconds per page.

The advantages of dot matrix printers include their cost-effectiveness. The cost of consumables for them is the lowest, and the dot matrix printer itself is inexpensive. Other advantages of dot matrix printers are determined by the impact principle of operation, which allows you to print several copies at once using special self-copying paper. The advantages of matrix technology include the ability to print on materials with non-standard sizes. This can be rolled paper, cardboard and even passports and passbooks.

The disadvantages of dot matrix printers include relatively low printing speed and unpleasant noise during operation. Multicolor printing is not possible on dot matrix printers.

In inkjet printers, images are created by microdroplets of special inks of different colors that are ejected through nozzles in the print head. Up to a million droplets are released in one second. This allows you to use any paper for printing, including cardboard.

Inkjet printers are the most popular of all types of printers. The advantages of inkjet printers include:

Low price (3 times lower compared to laser printers);

Low noise level compared to dot matrix printers;

Cheapest color printing.

A good inkjet printer can print not only text materials, but also documents with color photographs and diagrams.

The disadvantages of inkjet printers include:

Instability of printed text to water, light and friction;

The need to use special security paper to obtain color images;

Despite the relative cheapness of the printer, its operation requires serious expenses due to the frequent replacement of expensive cartridges.

Repairing the print head costs an amount almost equal to the cost of the printer itself;

Laser printers use a laser beam to print. The printer has a drum roller coated with a semiconductor substance that can become electrified when irradiated with a laser. The mirror scan causes a pulsating laser beam to slide along the lines along the drum. Flashes of the beam occur in those places where the image of the dots should be.

The smallest particles of dry paint (toner), which is located in the container under the drum, are attracted to the areas electrified by the laser. Then the roller is rolled over a sheet of paper, and the paint transfers to it. Fixing the image on paper is carried out by melting the toner with a special drum-oven.

Laser printers provide the fastest printing speeds of any printer and do not require special paper.

The disadvantages of laser printers include their high cost and high power consumption. It is not recommended to be used in an apartment due to the large amount of ozone it emits during operation. Ozone is an oxidizing agent and in overdose is harmful to health.

Scanners. A scanner is a device that allows you to enter images of texts, drawings, photographs directly from a paper document (Fig.) into a computer.

Rice. Scanners: Left - roller; on the right - tablet; below - manual

Scanners are classified according to the color of the input images into black-and-white and color and according to the method of use - into hand-held and desktop.

Handheld scanners are the simplest in design: they are moved manually across the image. Desktop scanners are divided into flatbed and roller scanners. Flatbed scanners are the most common; They allow you to scan both sheet and bound (book) documents. Roller scanners are the most automated, but the documents being scanned should only be sheet-fed.

Computer speakers. The built-in signal speaker in the computer is not designed to provide high-quality sound, so acoustic speakers are used to listen to music recordings. The principle of their design is similar to the design of speaker systems for household audio equipment. Depending on the type of amplifier, active and passive speakers are distinguished.

For passive speakers, the signals are amplified by an amplifier located on the sound card inside the system unit. In this case, the analog signal is exposed to numerous electrical interferences, which leads to acoustic distortion.

In active speakers, the amplifier is located in one of the speakers (outside the system unit), which helps improve sound quality.

Modems. A modem is a device for exchanging information with other computers over the telephone network. It connects the computer to the phone. The term "modem" is formed from two words (MODULATION-DEMODULATION). The modem modulates and demodulates information, that is, it converts digital signals from the computer into analog signals compatible with the phone connected to it and, conversely, receives incoming analog signals from the phone and converts them into digital signals compatible with the computer connected to it. A modem is required to connect to electronic networks on the Internet and to work with e-mail.

A fax modem is a modem for sending and receiving images. The sequence of operation of the fax system is as follows: optical scanning of the image, modulation and transmission of signals via communication channels, demodulation and making copies. Most modern modems are also fax modems.

Uninterruptible power supplies. If there is a sudden change in voltage parameters or a complete loss of electrical current, the data contained in the computer's operating memory may be irretrievably lost.

Therefore, when selling a computer, an uninterruptible power supply (UPS) is always offered. The UPS includes a rechargeable battery, which is constantly being recharged and in the event of a voltage drop, its energy is used to power the computer for 15-20 minutes for emergency shutdown.

Peripheral devices of a personal computer are connected to its interfaces and are designed to perform auxiliary operations. Thanks to them, the computer system gains flexibility and versatility.

By purpose peripheral devices can be divided into:

Data input devices;

Data output devices;

Storage devices;

Data exchange devices.

Character input devices

Special keyboards. The keyboard is the main data input device. Special keyboards are designed to improve the efficiency of the data entry process. This is achieved by changing the shape of the keyboard, the layout of its keys, or the method of connection to the system unit.

Keyboards that have a special shape, designed taking into account ergonomic requirements, are called ergonomic keyboards. It is advisable to use them at workplaces intended for entering a large amount of character information. Ergonomic keyboards not only increase typist productivity and reduce overall fatigue during the workday, but also reduce the likelihood and severity of a number of diseases, such as carpal tunnel syndrome and osteochondrosis of the upper spine.

The key layout of standard keyboards is far from optimal. It has been preserved from the days of early examples of mechanical typewriters. Currently, it is technically possible to manufacture keyboards with an optimized layout, and there are examples of such devices (in particular, these include Dvorak keyboard). However, the practical implementation of keyboards with a non-standard layout is questionable due to the fact that working with them requires special training. In practice, only specialized workplaces are equipped with such keyboards.

According to the method of connection to the system unit, there are wired And wireless keyboards. Information transmission in wireless systems is carried out by an infrared beam. The typical range of such keyboards is several meters. The signal source is the keyboard.

Command control devices. Special manipulators. In addition to a regular mouse, there are other types of manipulators, for example: trackballs, penmouses, infrared mice.

Trackball Unlike a mouse, it is installed stationary, and its ball is driven by the palm of the hand. The advantage of a trackball is that it does not require a smooth working surface, which is why trackballs are widely used in portable personal computers.

Penmouth is an analogue of a ballpoint pen, at the end of which, instead of a writing unit, a unit is installed that records the amount of movement.

Infrared mouse differs from the usual one in the presence of a wireless communication device with the system unit.

For computer games and in some specialized simulators, lever-type manipulators are also used (joysticks) and similar ones joypads, gamepads And steering-pedal devices. Devices of this type are connected to a special port on the sound card, or to a port USB.

Graphics input devices. To enter graphic information use scanners, graphics tablets (digitizers) And digital cameras. It is interesting to note that using scanners you can also enter symbolic information. In this case, the source material is entered graphically and then processed with special software. (pattern recognition programs).

Flatbed scanners. Flatbed scanners are designed to input graphic information from transparent or opaque sheet material. The principle of operation of these devices is that a beam of light reflected from the surface of a material (or passing through a transparent material) is detected by special elements called charge coupled devices (CCDs).

The main consumer parameters of flatbed scanners are:

Resolution;

Performance;

Dynamic range;

Maximum size of scanned material.

Handheld scanners. The operating principle of hand-held scanners is basically the same as flatbed scanners. The difference is that pulling the CCD line in this case is done manually. The uniformity and accuracy of scanning are provided unsatisfactorily, and the resolution of a hand-held scanner is 150-300 dpi.

Drum scanners. In this type of scanner, the source material is fixed on the cylindrical surface of a drum that rotates at high speed. They are used for scanning source images that have high quality but insufficient linear dimensions (photo negatives, slides, etc.)

Form scanners. Designed for entering data from standard forms filled out mechanically or by hand. The need for this arises when conducting population censuses, processing election results and analyzing personal data.

Form scanners are not required to have high scanning accuracy, but performance plays an increased role and is the main consumer parameter.

Bar scanners. This type of hand-held scanner is designed to input data encoded in the form of a barcode. Such devices are used in retail trade networks.

Graphic tablets (digitizers). These devices are designed for entering artistic graphic information. There are several different operating principles for graphics tablets, but they all rely on fixing the movement of a special pen relative to the tablet. Such devices are convenient for artists and illustrators, as they allow them to create screen images using familiar techniques developed for traditional tools (pencil, pen, brush).

Digital cameras. Like scanners, these devices perceive graphic data using charge-coupled devices arranged in a rectangular matrix. The main parameter of digital cameras is resolution, which is directly related to the number of CCD cells in the matrix.

Data output devices. Printing devices are used as data output devices, additional to the monitor ( printers), allowing you to receive copies of documents on paper or transparent media. Based on the principle of operation, there are matrix, laser, LED and inkjet printers.

Dot matrix printers. These are the simplest printing devices. Data is printed onto paper in the form of an imprint produced by striking cylindrical rods (“needles”) through an ink ribbon. The print quality of dot matrix printers directly depends on the number of needles in the print head. The most widespread are 9-needle And 24-needle dot matrix printers.

Laser printers. Laser printers provide high quality printing that is not inferior to, and in many cases superior to, printing. They also feature high print speeds, measured in pages per minute. (ppm -page per minute). As in dot matrix printers, the final image is formed from individual dots

The operating principle of laser printers is as follows:

In accordance with the incoming data, the laser head emits light pulses that are reflected from the mirror and hit the surface of the photosensitive drum;

Horizontal scanning of the image is performed by rotating the mirror;

Areas of the surface of the photosensitive drum that have received a light pulse acquire a static charge;

As the drum rotates, it passes through a container filled with a coloring compound (toner), and the toner is fixed to areas that have a static charge;

With further rotation of the drum, its surface comes into contact with the paper sheet, resulting in the transfer of toner to the paper;

A sheet of paper with toner applied to it is pulled through a heating element, causing the toner particles to sinter and become fixed to the paper.

TO basic parameters laser printers include:

Resolution, dpi (dots per inch - dots per inch);

performance (pages per minute);

Size of paper used;

Amount of own RAM.

When choosing a laser printer, you must also take into account the cost of a print, that is, the cost of consumables to produce one printed sheet of standard A4 format. Consumables include toner and drum, which lose their properties after printing a certain number of prints. The unit of measurement is cent per page(meaning US cents). Currently, the theoretical limit for this indicator is about 1.0-1.5. In practice, mass-market laser printers provide values from 2.0 to 6.0.

The main advantage of laser printers is the ability to produce high-quality prints. Middle-class models provide print resolutions of up to 600 dpi, and professional models provide print resolutions of up to 1200 dpi.

LED printers. The operating principle of LED printers is similar to that of laser printers. The difference is that the light source is not a laser head, but a line of LEDs. Since this ruler is located across the entire width of the printed page, there is no need for a horizontal scanning mechanism and the entire design is simpler, more reliable and cheaper. The typical print resolution for LED printers is about 600 dpi.

Inkjet printers. In inkjet printing devices, the image on paper is formed from spots formed when drops of dye hit the paper. The release of microdroplets of dye occurs under pressure, which develops in the print head due to vaporization. In some models, the drop is ejected with a click as a result of the piezoelectric effect - this method allows for a more stable drop shape, close to spherical.

The quality of the printed image largely depends on the shape of the drop and its size, as well as on the nature of absorption of the liquid dye by the surface of the paper. Under these conditions, the viscosity properties of the dye and the properties of the paper play a special role.

The positive properties of inkjet printing devices include a relatively small number of moving mechanical parts and, accordingly, the simplicity and reliability of the mechanical part of the device and its relatively low cost. The main disadvantage, compared to laser printers, is the instability of the resulting resolution, which limits the possibility of their use in black-and-white halftone printing.

At the same time, today inkjet printers have found very wide application in color printing. Due to their simplicity of design, they are far superior to color laser printers in terms of quality/price. With a resolution above 600 dpi, they make it possible to obtain color prints that are superior in quality to color prints obtained by photochemical methods.

When choosing an inkjet printer, be sure to keep in mind the parameter of the cost of printing one print. Despite the fact that the price of inkjet printing devices is noticeably lower than laser ones, the cost of printing one print on them can be several times higher.

Storage devices. The need for external data storage devices arises in two cases:

When a computing system processes more data than can be accommodated on the underlying hard drive;

When data is of high value and it is necessary to perform regular backups to an external device (copying data to a hard drive is not a backup and only creates the illusion of security).

Currently, several types of devices using magnetic or magneto-optical media are used for external data storage.

Streamers- These are magnetic tape drives. They are distinguished by a relatively low price. The disadvantages of streamers include low productivity(it is connected, first of all, with the fact that magnetic tape is a sequential access device) and insufficient reliability (in addition to electromagnetic interference, tape drives experience increased mechanical stress and can physically fail).

The capacity of magnetic cassettes (cartridges) for streamers is up to several hundred MB. Further increase in capacity due to increased recording density reduces storage reliability, and increase in capacity due to increasing tape length is limited by low data access time.

ZIP drives are produced by Iomega, a company specializing in creating external storage devices. The device works with disk media that are slightly larger in size than standard floppy disks and have a capacity of 100/250 MB. ZIP drives are available in internal and external versions. In the first case, they are connected to the hard drive controller of the motherboard, and in the second - to a standard parallel port, which negatively affects the data exchange speed.

Drives HiFD. The main disadvantage of ZIP drives is their lack of compatibility with standard 3.5-inch floppy disks. Devices have this compatibility HiFD Sony company. They allow the use of both special media with a capacity of 200 MB and regular floppy disks. Currently, the proliferation of these devices is constrained by the increased price.

JAZ drives. This type of drive, like ZIP drives, is manufactured by Iomega. In terms of its characteristics, JAZ media is close to hard drives, but unlike them, it is removable. Depending on the drive model, one disk can accommodate 1 or 2 GB of data.

Magneto-optical devices. These devices are widely used in high-end computer systems due to their versatility. With their help, problems of backup, data exchange and accumulation are solved. However, the rather high cost of drives and media does not allow them to be classified as devices of mass demand.

Data exchange devices. Modem. A device designed to exchange information between remote computers via communication channels is usually called modem(MODulator + DEModulator). In this case, a communication channel is understood as physical lines (wire, fiber optic, cable, radio frequency), the method of their use (switched and dedicated) and the method of data transmission (digital or analog signals). Depending on the type of communication channel, transmitting and receiving devices are divided into radio modems, cable modems and others. The most widely used modems are those aimed at connecting to dial-up telephone communication channels.

Digital data entering the modem from a computer is converted by modulation (amplitude, frequency, phase) in accordance with the selected standard (protocol) and sent to the telephone line. The receiver modem, which understands this protocol, performs reverse conversion (demodulation) and sends the recovered digital data to its computer. Thus, remote communication between computers and data exchange between them is ensured.

TO basic consumer parameters modems include:

Performance (bit/s);

Supported communication and error correction protocols;

Bus interface if the modem is internal (ISA or PCI).

The amount of data transmitted per unit of time depends on the performance of the modem. The efficiency of interaction of a given modem with adjacent modems (the probability that they will interact with each other under optimal settings) depends on the supported protocols. At present, only the ease of installation and configuration of the modem currently depends on the bus interface (in the future, with the general improvement of communication channels, the bus interface will begin to influence performance).

Introduction........................................................ ........................................................ .......... 2

1. Concept and types of computer peripheral devices.................................... 3

1.1. Definition and purpose of peripheral devices.................................... 3

1.2. Classification of peripheral devices................................................................. 3

2. Main characteristics of computer peripheral devices.................................. 5

2.1. Input devices................................................................... ................. 5

2.2. Output devices................................................................... .............. 9

2.3. Storage devices................................................................... .......... 12

2.4. Information exchange devices................................................................... ........... 13

Conclusion................................................. ........................................................ .... 14

Literature................................................. ........................................................ .... 15

Glossary................................................. ........................................................ ...... 16

Introduction

This work examines the peripheral devices of a personal computer. These devices are actively used by users and their use ensures the efficiency of the PC. Operating a computer without peripheral devices is often impossible or difficult. All this determines the relevance of the chosen topic.

The object of research is modern peripheral devices used for standard personal computers.

The subject of the study is the technical characteristics and operating principles of peripheral devices.

The purpose of the work is to reveal the circuit and principles of using peripheral devices.

Tasks solved during the work:

Define the concept and purpose of peripheral devices;

Classify peripheral devices;

Describe information input devices;

Describe information output devices;

Describe information storage devices;

Describe information exchange devices.

When writing the work, textbooks and special literature on personal computers and peripheral devices were used.

The first chapter describes the general properties and principles of use of peripheral devices, as well as their classification; The second chapter examines the characteristics of the devices themselves according to the classification given in Chapter 1.

1. Concept and types of computer peripheral devices

1.1. Definition and purpose of peripheral devices

The wealth of possibilities provided by a computer is due not only to the fact that a computer is a universal mechanism for processing information, but also to the fact that a wide variety of devices can be connected to it for input, output, processing and storage of information.

The main purpose of peripheral devices is to ensure the entry of programs and data into the computer from the environment for processing, as well as the output of the results of the computer in a form suitable for human perception or for transfer to another computer, or in another necessary form. Peripheral devices to a large extent determine the possibilities of using a computer.

Computer peripheral devices include external storage devices designed for storing and further using information, input-output devices designed for exchanging information between the machine's RAM and storage media, either other computers or the operator. Input devices can be: keyboard, disk system, mouse, modems, microphone; weekends - display, printer, disk system, modems, sound systems, other devices. With most of these devices, data exchange occurs in digital format. To work with a variety of sensors and actuators, analog-to-digital and digital-to-analog converters are used to convert digital data into analog and vice versa.

1.2. Classification of peripheral devices

Peripheral devices of a personal computer are connected to its interfaces and are designed to perform auxiliary operations. Thanks to them, the computer system acquires flexibility and versatility.

According to their purpose, peripheral devices can be divided into:

Data input devices;

Data output devices;

Storage devices;

Data exchange devices.

In this case, data input devices are divided into character data input devices, graphic data input devices, and command control devices.

Data output devices, in the understanding of some authors, are printers. Although output devices can undoubtedly include a monitor and various devices designed to output audio information (speakers, for example).

Information exchange devices primarily include modems, with the help of which such exchange occurs.

Some devices, depending on the application situation, can be input and output. So, using a disk drive or modem, information can be entered into a computer, or it can be output for the purpose of transferring it to another computer. Input devices (scanner, keyboard, mouse) cannot be output devices, and output devices (printer, monitor) cannot be input devices.

2. Main characteristics of computer peripheral devices

2.1. Input devices

The keyboard is the main data input device. Special keyboards are designed to improve the efficiency of the data entry process. This is achieved by changing the shape of the keyboard, the layout of its keys, or the method of connection to the system unit.

Keyboards that have a special shape, designed taking into account ergonomic requirements, are called ergonomic keyboards. It is advisable to use them at workplaces intended for entering a large amount of character information. Ergonomic keyboards not only increase typist productivity and reduce overall fatigue during the workday, but also reduce the likelihood and severity of a number of diseases, such as carpal tunnel syndrome and osteochondrosis of the upper spine.

The key layout of standard keyboards is far from optimal. It has been preserved from the days of early examples of mechanical typewriters. Currently, it is technically possible to manufacture keyboards with an optimized layout, and there are examples of such devices (in particular, the Dvorak keyboard is one of them). However, the practical implementation of keyboards with a non-standard layout is questionable due to the fact that working with them requires special training. In practice, only specialized workplaces are equipped with such keyboards.

Depending on the method of connection to the system unit, there are wired and wireless keyboards. Information transmission in wireless systems is carried out by an infrared beam. The typical range of such keyboards is several meters. The signal source is the keyboard.

Command control devices include special manipulators.

On desktop computers, the most commonly used pointing device is the mouse, which is a small box (usually gray) with two or three buttons that fits easily in the palm of your hand. Together with a wire for connecting to a computer, this device really resembles a mouse with a tail. When you move the mouse across a table or other surface on the computer screen, the mouse pointer (usually an arrow) moves accordingly. When it is necessary to perform a particular action, for example, execute a menu item on which the mouse pointer is positioned, the user presses one or another mouse button.

In addition to a regular mouse, there are other types of manipulators, for example: trackballs, penmouses, infrared mice.

The trackball, unlike a mouse, is installed stationary, and its ball is driven by the palm of the hand. The advantage of a trackball is that it does not require a smooth working surface, which is why trackballs are widely used in portable personal computers.

Penmouse is an analogue of a ballpoint pen, at the end of which, instead of a writing unit, there is a unit that records the amount of movement.

An infrared mouse differs from a regular mouse in the presence of a wireless communication device with the system unit.

For computer games and in some specialized simulators, lever-type manipulators (joysticks) and similar joypads, gamepads and steering-pedal devices are also used. Devices of this type are connected to a special port on the sound card or to a USB port.

To enter graphic information, scanners, graphics tablets (digitizers) and digital cameras are used. It is interesting to note that using scanners you can also enter symbolic information. In this case, the source material is entered in graphical form, after which it is processed by special software (pattern recognition programs).

Flatbed scanners are designed to input graphic information from transparent or opaque sheet material. The principle of operation of these devices is that a beam of light reflected from the surface of a material (or transmitted through a transparent material) is detected by special elements called charge-coupled devices (CCDs). Typically, CCD elements are structurally designed in the form of a ruler located along the width of the source material. The movement of the ruler relative to the sheet of paper is performed by mechanically pulling the ruler while the sheet is stationary, or by pulling the sheet while the ruler is stationary.

The main consumer parameters of flatbed scanners are:

Resolution; in productivity;

Dynamic range;

Maximum size of scanned material.

The resolution of a flatbed scanner depends on the density of placement of CCD devices on the ruler, as well as on the accuracy of the mechanical positioning of the ruler during scanning. Typical indicator for office use: 600-1200 dpi (dpi - dots per inch - dots per inch). For professional use, 1200-3000 dpi is typical.

The performance of a scanner is determined by the duration of scanning a sheet of standard-sized paper and depends both on the perfection of the mechanical part of the device and on the type of interface used to interface with the computer.

Dynamic range is determined by the logarithm of the ratio of the brightness of the lightest areas of the image to the brightness of the darkest areas. The typical indicator for office scanners is 1.8-2.0, and for professional scanners - from 2.5 (for opaque materials) to 3.5 (for transparent materials).

The operating principle of hand-held scanners is basically the same as flatbed scanners. The difference is that pulling the CCD line in this case is done manually. The uniformity and accuracy of scanning are provided unsatisfactorily, and the resolution of a hand-held scanner is 150-300 dpi.

Let's look at drum scanners. In this type of scanner, the source material is fixed on the cylindrical surface of a drum that rotates at high speed. Devices of this type provide the highest resolution (2400-5000 dpi) due to the use of photomultipliers rather than CCDs. They are used for scanning source images that have high quality but insufficient linear dimensions (photo negatives, slides, etc.)

Form scanners. Designed for entering data from standard forms filled out mechanically or by hand. The need for this arises when conducting population censuses, processing election results and analyzing personal data.

Form scanners are not required to have high scanning accuracy, but performance plays an increased role and is the main consumer parameter.

Bar scanners are designed to input data encoded in the form of a bar code. Such devices are used in retail trade networks.

Graphic tablets (digitizers) are designed for entering artistic graphic information. There are several different operating principles for graphics tablets, but they all rely on fixing the movement of a special pen relative to the tablet. Such devices are convenient for artists and illustrators, as they allow them to create screen images using familiar techniques developed for traditional tools (pencil, pen, brush).

Digital cameras, like scanners, perceive graphic data using charge-coupled devices combined into a rectangular matrix. The main parameter of digital cameras is resolution, which is directly related to the number of CCD cells in the matrix. The best consumer models currently have up to 1 million CCD cells and, accordingly, provide image resolutions of up to 800x1200 pixels. For professional models these parameters are higher.

2.2. Output devices

Since the use of the monitor for visual display of data, there has been a great design improvement in its functions. If at first the cathode ray tube of a conventional television receiver was used as a monitor, then later the requirements for it increased. In particular, in the monochrome MDA standard the resolution was 720x350 pixels. In the next color standard, CGA, created in 1982, has 640x200 pixels, EGA in 1984 has 640x350, VGA in 1987 has 640x480, SVGA has 800x600. Now the standard monitor capabilities are 1024x768 with 32-bit color representation, further expansion of the resolution of 1280x1024 pixels is possible. This allows you to use WYSIWYG mode when displaying documents - a full-match mode, that is, the image on the screen appears identical to what will ultimately appear on the printer.

The display system consists of two parts: the display adapter and the monitor itself. Monitor adapters are divided according to the supported standard (EGA, VGA, SVGA), bus width (8-bit, 16 or more), frame rate, line frequency can be used with graphics coprocessors, the amount of memory chips used (up to 4 MB or more) . Displays differ in resolution, dot pitch in a line, scan frequency, scan type (full or interlaced), and screen size. The adapter continuously scans the video memory and generates a TV signal, which is fed to the monitor. After receiving a copy of the contents of the video memory, this data is embedded in the TV signal. The TV signal, in which the contents of the video memory are encoded, is output via cable to the monitor. The monitor processes the TV signal with data from video memory and displays it on the screen.

As data output devices, additional to the monitor, printing devices (printers) are used, which make it possible to obtain copies of documents on paper or transparent media. Based on the principle of operation, there are matrix, laser, LED and inkjet printers.

Dot matrix printers are the simplest printing devices. Data is printed onto paper in the form of an imprint produced by striking cylindrical rods (“needles”) through an ink ribbon. The print quality of dot matrix printers directly depends on the number of needles in the print head. The most common are 9-pin and 24-pin matrix printers. The latter make it possible to obtain document prints that are not inferior in quality to documents written on a typewriter.

Laser printers provide high quality printing that is not inferior to, and in many cases superior to, printing. They are also distinguished by their high printing speed, which is measured in pages per minute (ppm). As in dot matrix printers, the final image is formed from individual dots. Laser printers use the principle of xerography: an image is transferred to paper from a special drum to which particles of ink (toner) are electrically attracted.

In inkjet printing devices, the image on paper is formed from spots formed when drops of dye hit the paper. The release of microdroplets of dye occurs under pressure, which develops in the print head due to vaporization. In some models, the drop is ejected with a click as a result of the piezoelectric effect - this method allows for a more stable drop shape, close to spherical.

2.3. Storage devices

One of the most common devices for storing information is a disk drive. Floppy disks (floppy disks) allow you to copy documents and programs from one computer to another, as well as store information that is not constantly used on the computer. Almost all computers have at least one floppy drive. However, floppy disks are used less and less as a storage medium, since they are not reliable enough and can store significantly less data than other storage media. The most common floppy disk sizes are 3.5 and 5.25 inches (89 and 133 mm). The most reliable are 3.5-inch floppy disks; currently they are mainly used in PCs.

Another equally common information storage device is CD-ROM, which reads information from a CD. CD-ROMs are basically an adaptation of compact discs from digital audio recording systems. Digital data is written to the disc using a special recording device that makes microscopic pits on the surface of the disc. The information encoded by these pits can be read simply by detecting the change in reflectance (the pits will be darker than the background of the shiny silver disk). Once the CD-ROM is stamped using the presses, the data can no longer be changed; the indentations will be forever.

Although WORM drives are similar to CD ROMs, they are capable of writing "inside" the disc. Like CD ROMs, WORM devices store data by physically altering the surface of the disk, but they do it differently. It is difficult to pit in a WORM environment because the surface is protected by transparent plastic. Instead of pitting, WORM discs use dimming. That is, WORM systems simply darken the surface or, more precisely, evaporate part of it. Once you have written information to disk, in the future you can only read information from the WORM disk. The durability of WORM disks is estimated at at least 10 years. The amount of data stored on one WORM and CD ROM disk is 650 MB.

Other drives (including streamers, Z/P drives, etc.) can also be used to store information, but they are not as common as those described above.

2.4. Communication devices

For all users who want to use global electronic networks such as InterNet, work with e-mail, access their company's local network from outside the office, send and receive faxes using a computer, etc., a modem or fax modem is required. A modem is a device for exchanging information with other computers through the telephone network. Fax modem is a device that combines the capabilities of a modem and the means for exchanging fax images with other fax modems and conventional telefax machines. Most modern modems are fax modems. Some modems have voice capabilities and can, for example, be used as an answering machine.

Modems can be internal (in the form of an electronic board connected to the computer's ISA bus), external - in the form of a separate device, and in the form of a PC card for connecting to a laptop computer. Modems differ from each other in maximum data transfer speed and supported communication protocols.

Conclusion

1. The main purpose of peripheral devices is to ensure the entry of programs and data into the computer from the environment for processing, as well as the output of the results of the computer in a form suitable for human perception or for transfer to another computer, or in another necessary form.

2. Peripheral devices can act as both input and output devices, and are divided into input, output, information storage, and information exchange devices.

3. Input devices include primarily the most common one - the keyboard. In addition to the keyboard, various manipulators are used to control programs, input and output of information (the most common manipulator is the mouse). There are also graphic information input devices: scanners, digital cameras and digital cameras that are capable of storing an image from the external environment and transmitting it as a file to a computer.

4. Output devices are primarily monitors and printers. Moreover, printers are divided according to their operating principles into matrix, inkjet and laser. Currently, laser printers are increasingly used, although the use of inkjet printers is due to the possibility of inexpensive color printing, and the use of matrix printers is due to the low cost of the printer itself and consumables.

5. Data storage devices: primarily disk drives (nowadays, 3.5-inch ones are usually used). Capacitive (up to 650 MB) CD-ROMs are also widely used, as well as similar WORM systems that allow you to burn CDs once.

6. Exchange devices primarily include modems. The modem is used to communicate with other computers via a telephone line. Currently, the capabilities of modems are expanding: fax modems, modems with answering machines, etc. appear.

Literature

1. Computer science. Basic course: textbook for universities / Ed. S.V. Simonovich. – St. Petersburg: Peter, 2001.

2. Komyagin V.B., Kotsyubinsky A.O. Modern self-instruction manual for working on a computer: Quick start. – M.: Tridmor, 2000.

3. Petrachenkov A.V. Personal computer – simple and clear. – Smolensk: Rusich, 1997.

4. Roche Winn L. Bible on personal computer modernization. - Mn.: IPP Tivali-Style, 1995.

5. Figurnov V.E. IBM PC for the user: a short course. – M.: Infra-M, 1998.

Glossary

CD-ROM – a device for reading information from compact discs;

cps - characters per second - number of characters printed per second (indicator of dot matrix printer operation);

dpi - dots per inch - number of dots per inch - characteristic of the operation of a scanner, printer;

Draft - draft printing mode;

EGA - display adapter providing a resolution of 640x350 pixels with 16 colors;

EGA monitor - a monitor (display) designed to work with EGA adapters;

ISA is a type of internal computer data bus used in most personal computers to interface with low-speed devices.

NLQ (Near Letter Quality), a printing mode that provides print quality close to that of a typewriter;

Normal - normal printing mode;

SVGA (SuperVGA) - display adapters that provide both the capabilities of a VGA adapter and work in graphics mode with a resolution of 800x600 pixels, and often in higher resolution modes; often SVGA also refers to monitors (displays) that can work with SVGA adapters and provide a resolution of 800x600 pixels or more;

USB – special port for connecting peripheral equipment;

VGA - display adapter providing a resolution of 640x480 pixels with 16 colors;

VGA monitor - a monitor (display) designed to work with VGA adapters;

Introduction

Chapter I. Computer peripherals

1.2 Input devices

1.3 Output devices

Chapter II. Create an educational presentation

2.1 Computer presentations

2.2 Software selection

2.3 Presentation structure

Conclusion

Literature

Introduction

The life of modern society is extremely difficult to imagine without a computer. Billions of people across the planet use them for work, leisure and education. The amazing capabilities that a computer has today simply cannot be counted. A PC is no longer considered a luxury item. This is an indispensable assistant, with which people can do many common things easier and faster than before. For example, write letters, keep convenient records of cash expenses and organize business notes, lists of addresses and contacts in the phone book. You can also view photos, play music and video recordings using your computer.

The Internet computer network allows you to find the most useful and varied information, because the World Wide Web has almost everything! You can also use the network to communicate with friends and relatives, even if you live very far from each other. But it would be impossible to perform all these actions without peripheral devices.

There are quite a lot of sources of information on the topic “Computer Peripheral Devices”, but to get a complete picture it is necessary to collect this scattered information together, systematize and structure it.

All of the above allows us to formulate the purpose of the work: using a graphical presentation editor MS Power Point to create an electronic textbook "PC Peripherals".

Collect and analyze material on the topic “PC Peripherals”.

Structure the information received.

Develop an electronic textbook using the graphical presentation editor MSPowerPoint.

Chapter I. Computer peripherals

1.1 Computer hardware

Information is one of the most valuable resources of society, along with such traditional material types of resources as oil, gas, minerals, etc., which means that the process of its processing, by analogy with the processes of processing material resources, can be perceived as technology. Then the following definition is valid.

Information technology- a process that uses a set of means and methods for collecting, processing and transmitting data (primary information) to obtain new quality information about the state of an object, process or phenomenon (information product).

In modern society, the main technical means of information processing technology is the personal computer, which has significantly influenced both the concept of construction and the use of technological processors, and the quality of the resulting information. The introduction of the personal computer into the information sphere and the use of telecommunications have determined a new stage in the development of information technology and, as a consequence, a change in its name by adding one of the symbols: “new”, “computer”, or “modern”. The adjective “computer” is emphasized that the main technical means of its implementation is a computer.

Computer technology is an information process that results in the creation of an information product based on computer data processing.

The use of a computer as a tool for working with information is very diverse and multifaceted. With its help, you can browse your digital library in a few seconds and find the information you need. Special computer programs have been developed that allow, for example, a shoemaker to experiment with the shape and texture of the shoe model being created. With the help of a computer, cars are now being tested, the structure of molecules is being studied, houses are being designed and spaceships are being launched. Whatever you do - draw, play, count, type, the computer obediently follows your commands. But the computer itself cannot perform all these actions; for this it needs special devices called peripherals.

1.2 Input devices

Input Devices- hardware for converting information from a form understandable to a person into a form perceived by a computer.

Fig.1. Classification of input devices

Devices with keyboard input.

Keyboard. The standard device for entering information into a computer is the keyboard. With its help, you can enter numeric and text information, as well as various commands and data. Typically, information entered from the keyboard is displayed on the monitor screen for control purposes. The location where information is entered on the screen is indicated by a special icon called a cursor. The appearance of the cursor may vary depending on the program used and operating mode. This could be a blinking dash, a rectangle, etc.

Typically, a 101-103-key American standard keyboard is used. In addition to the keyboard, there are membrane and touch keyboards. The keys of the alphanumeric field are additionally marked with letters of the national alphabet. If your computer has an operating system that is not configured to work in the national alphabet mode (non-localized version), then an additional special program is required - a keyboard driver. In localized versions, the keyboard driver is included in the package.

In the modern computer market, ergonomic keyboards and special wrist pads are very popular, providing the most comfortable working conditions.

Manipulators.

Mouse. Next to the keyboard is a movable device called a mouse. There is a ball on the bottom surface of the mouse. Moving the mouse on a flat surface (table, rug) causes the ball to rotate. At the same time, it interacts with sensors inside the mouse body, resulting in a signal that causes the mouse pointer to move on the monitor screen. There are 2 or 3 buttons on the top surface of the mouse. Pressing a particular button (*a mouse click is perceived by the computer as an indication to perform some specified action. Using a mouse allows you to more quickly and conveniently control the operation of various programs.

The quality of a mouse is determined by its resolution, which is measured by the number of dots per inch - dpi (dotperinch). This characteristic determines how accurately the mouse pointer will move across the screen. For middle-class mice, the resolution is 400-800 dpi. Different types of mice differ from each other: in the way they read information (mechanical, optical-mechanical and optical), in the number of buttons (2- and 3-button mice), in the method of connection to the computer (wired - connected using a cable; wireless, or “tailless” mouse - connection to the computer is provided by an infrared signal, which is perceived by a special port).

Mouse design involves various forms of structures. The most popular are ergonomic mice, which have a streamlined surface and ensure natural placement of the hand on its surface. New is a wireless bat that works almost anywhere you want. On the desk it works like a regular mouse; If you lift it and press the button on the base, then such a mouse can be used directly in the air at a distance of up to 10 meters from the stand.

Trackball or trackball, resembles an upside-down mouse. You don’t need to move it around the table like a mouse. In a trackball, the ball is rotated by hand and the rotation is also converted into moving the pointer across the screen. It is very convenient in cases where there is little space, as it does not require a mat or space to move the manipulator around the table.

Joystick or control stick, was designed specifically for gaming. Just like a mouse and trackball, it allows you to move a cursor or graphic object across the monitor screen. The joystick is a handle that tilts in all directions, and several buttons on a small panel for performing simple actions.

Joysticks have different numbers of buttons and different directions for moving the cursor around the screen. In order to comply with ergonomic requirements, the joystick handle has a shape that follows the relief of the hand when grasping the handle.

Touch devices.

Touch screen. A touch or tactile screen is a surface that is covered with a special layer. Touching a specific location on the screen selects a task to be performed by the computer or a command from the on-screen menu. For example, during the Olympics, touch screens help athletes, coaches, and correspondents quickly select the information they are interested in about the results of competitions, the composition of teams, etc. by pointing your finger in the corresponding menu.

The touch screen also allows you to move objects. It is easy to use, especially when you need quick access to information. Such input devices can be seen in banking computers, airports, as well as in the military and industrial sectors.

Light pen. A light pen is similar to a regular pencil, at the tip of which there is a special device - a light-sensitive element. The contact of the pen with the screen closes the photoelectric circuit and determines where data is entered or corrected. If you move this stylus around the screen, you can draw or write on the screen as you would on a piece of paper.