Input and output device lecture


Input devices convert information from a human-readable form to a computer-readable digital form. Modern computers can process numerical, text, graphics, audio and video information.

Keyboard. allows you to enter numerical and text information, as well as various commands and data into the computer.

The microphone is used to input sound information, it is connected to the input of the sound card.

The scanner is used for optical input into a computer and converting images (photographs, drawings, drawings) into digital format, for keyboardless text input.

There are handheld, sheet-feed, flatbed and projection scanners. A variety of projection scanners are slide scanners designed for scanning photographic films. In high-quality printing, drum scanners are used, in which a photomultiplier tube (PMT) is used as a photosensitive element.

Webcam is a digital video or camera capable of capturing video images in real time for further transmission over a computer network.

Touch screen. an information input device, which is a screen that responds to touching it.

A graphics tablet (digitizer, digitizer) with a light pen is a device for entering freehand drawings and handwritten text directly into a computer.

Special sensors. connected to a computer, allow you to measure and enter into its memory such numerical characteristics of the environment as temperature, humidity, pressure and much more.

Pointing (coordinate) input devices directly enter information by pointing the cursor on the monitor screen to the command or the place of data input. These devices are called manipulators:

Mouse. When you move it, the mouse pointer moves on the screen, with which you can point to objects and / or select them. Using the mouse keys, you can set one or another type of operation with an object.

Trackball. According to the principle of operation, the Track ball is best compared to a mouse that lies on the table with its belly up.

Joystick is a control device in computer games. It is a lever on a stand that can be deflected in two planes.

A gamepad is a two-handed remote control with thumbs used to control its controls. Gamepads provide interaction between the player and the game console.

The touchpad is used to move the cursor depending on the movements of the user’s finger and is used to replace the mouse in laptops. To move the cursor to full screen, just move your finger a little over the surface of the touchpad.

Pointing devices also include a touch screen and a graphics tablet.

Dance platform. also known as dance mat, dance mat or dance pad. flat game controller used in dance games.

The interactive whiteboard is a large touchscreen that works as part of a system that also includes a computer and projector. A projector projected an image of your PC desktop onto the surface of your interactive whiteboard. With the image projected onto the board, you can work, make changes and markups. All changes are recorded in the corresponding files on the computer, can be saved and later edited or rewritten to removable media. In this case, the electronic board works as Input Devices information. The board can be controlled with a stylus or by touching your finger. The communication between the whiteboard and the PC is two-way, and the finger or stylus (stylus, pen) of the interactive whiteboard works like a mouse.

The light pen looks like a ballpoint pen or pencil, connected with a wire to one of the computer’s I / O ports. Typically, a light pen has one or more buttons that can be pressed by the hand holding the pen. Pen input involves touching or drawing lines with the stylus across the surface of the monitor screen. The light pen was common during the spread of EGA graphics cards. The light pen cannot be used with conventional LCD monitors. This requires a special screen that can react to the light pen.


Output devices. peripheral devices that convert the results of processing digital machine codes into a form that is convenient for human perception or suitable for influencing the executive organs of the control object.

Monitor. a device for playing a video signal and visual display of information received from a computer. A modern monitor consists of a screen (display), a power supply, control boards and a case. Information for display on the monitor comes from an electronic device that generates a video signal (video card). A TV can also be used as a monitor.

CRT. monitor based on a cathode ray tube (CRT).

LCD. liquid crystal displays (eng. Liquid crystal display, LCD).

Plasma. based on a plasma display panel (eng.plasma display panel, PDP, gas-plazma display panel).

Projector. a video projector and a screen, placed separately or combined in one housing (as an option. through a mirror or a system of mirrors); and projection TV.

LED monitor. on LED technology (light-emitting diode. light-emitting diode).

OLED monitor. based on OLED technology (organic light-emitting diode. organic light-emitting diode).

Virtual retinal monitor is an output device technology that creates an image directly on the retina of the eye.

Laser. based on a laser panel (so far only being introduced into production).

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two-dimensional (2D). one image for both eyes;

three-dimensional (3D). a separate image is formed for each eye to obtain the effect of volume.

Screen size. determined by the diagonal length, most often in inches.

Resolution. the number of pixels horizontally and vertically.

Color depth. the number of bits to encode one pixel (from monochrome to 32-bit).

Pixel response time (not available on all monitor types).

Equipment for entering graphic information into a computer

There are various technical means that carry out the process of converting images into digital form, for example, scanners, digitizers (graphic tablets), digital cameras and video cameras. In each specific case, it is important to choose the right device, guided by its technical characteristics, in order to obtain a digitized image with the required detail and color gamut.

Scanner. this is a device for inputting color or black-and-white images into a personal computer.

The principle of operation of almost all types of scanners is the same. It is based on the fact that a directed beam illuminates individual points of the original image (original) and the reflected beam is perceived by a photosensitive receiver, where information about the “color” of the point is interpreted as a specific numerical value, which is transmitted through a certain interface to the computer.

As a rule, photosensitive elements are combined into a matrix in order to scan a whole area of ​​the original at the same time.

Scanners are divided into black and white and color according to the method of color perception.

Black and white scanners can, in the simplest case, only distinguish two values. black and white, which is sufficient to read the barcode. sophisticated scanners distinguish between grayscale.

Color scanners work on the principle of color addition, in which a color image is obtained by mixing three colors: red, green and blue.

According to the mechanism of movement of the matrix of light-sensitive elements relative to the original, the following types of scanners are distinguished: manual, drum, sheet, flatbed.

Hand-held scanners. these are relatively inexpensive devices of small size, convenient for on-line scanning of images from books and magazines. Scanning is done by manually moving the scanner over the original. Scanning bandwidth usually does not exceed 15 cm.The disadvantages of a handheld scanner include the dependence of the scan quality on the user’s skills and the inability to simultaneously scan relatively large images.

The drum scanner places the original to be scanned on the rotating drum. This scans the dotted area of ​​the image, and the scanning head moves along the drum at a very small distance from the original. Currently, these scanners are used only in the printing industry.

In sheet scanners, the image carrier is drawn along a ruler on which the light-sensitive elements are located. The width of the image is usually A4 format, and the length is limited by the capabilities of the computer used (the larger the image, the larger the file size where its digital copy is stored).

Scanners are connected to a personal computer through a special controller (for flatbed scanners, this is most often a SCSI controller). A scanner should always have an appropriate driver, since only a limited number of software applications have built-in drivers to communicate with a certain class of scanners.

When choosing a specific scanner model, it is necessary to take into account a number of characteristics associated with the technical capabilities of the model.

Resolution. the number of dots or raster cells from which the image is formed, per unit of length or area. The higher the resolution of the device, the finer details can be reproduced.

Hardware / Optical resolution of the scanner. this is one of the main characteristics of the scanner, which is directly related to the density of placement of sensitive elements on the scanner matrix. Measured in pixels per square inch of the image.

Interpolated resolution. resolution of the image obtained by mathematical processing of the original image. It has little to do with quality improvement. Often serves as an advertising gimmick for untrained users.

Depth of color. the number of bits of each pixel in a digital image, incl. issued by the scanner.

A fairly large number of scanner manufacturers are represented on the world market. The most popular models are produced by Hewlett-Packard, Agfa, Canon, Mustek.

Scanning of flat graphic documents. the matter is relatively simple: the original is placed on the glass plate of the flatbed scanner, the lid is closed and the machine is started up. But scanning in three dimensions that define our world is much more difficult and requires a lot of work, so until now this task for PC users has been almost insoluble.

However, a number of instruments have now been developed to display small to medium sized objects as accurate 3D files. An example is Immersion’s MicroScribe-3D device for digitizing three-dimensional objects, which uses modern advances in various branches of technological progress.

Device for digitizing three-dimensional objects MicroScribe-3D

Immersion has developed a unique mechanical digitizing technology that is compact, affordable and easy to use. The device is a tabletop device that looks like a miniature dental drill (9). Each MicroScribe-3D connection uses digital optical sensors that are unaffected by any environmental influences. The result: a versatile system that can work in virtually any environment and scan objects from any material.

But besides this, there are other 3D scanning technologies: ultrasound scanning, magnetic scanning, laser scanning.

Digitizer. it is a device for digitizing images used to create drawings and sketches on a computer. With the help of special software, it allows you to convert the movement of the operator’s hand into vector graphics. The digitizer was originally developed for computer-aided design (CAD) applications, as it requires determining and specifying the exact value of the coordinates of a large number of points. Unlike a mouse, a digitizer is able to accurately determine and process object coordinates.

The digitizer consists of a special tablet, which is a working surface and, in addition, performs various functions of controlling the corresponding software, and a light pen or, more often, a circular cursor, which are information input devices (10).

The principle of operation of the digitizer is based on fixing the position of the cursor using the grid built into the tablet. When you press the cursor button, its location on the tablet surface is fixed, and its coordinates are transmitted to the computer. The mesh consists of wire or printed conductors with a fairly large distance between adjacent conductors (3 to 6 mm).

One type of digitizer is a graphics or drawing tablet. It is a panel with an electromagnetic grill underneath. If you drag a special stylus across its surface, a stroke will appear on the monitor screen. The principle of absolute positioning is implemented in the tablet: an image drawn in the lower left corner of the tablet will appear in the lower left corner of the monitor screen. Typically, drawing tablets are the size of a mouse pad, but the work surface is slightly smaller.

Pressure-sensitive tablets are available, with which, by adjusting the pressure, you can get lines of different thickness on the screen.

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The special plastic film supplied with the flatbed allows you to copy the images underneath it onto paper originals. Tablets are connected to the serial port of a personal computer.

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The graphic tablet can be in different formats: from A2. for professional activities and less. for simpler jobs.

An important characteristic of a digitizer is the registerable number of degrees of depression of the electronic pen. In existing models, this value can vary from 1 to 256. The handler program uses this value, setting depending on it, for example, the thickness of the line being drawn (the stronger the pressure, the thicker the line).

The most popular models of the following companies: CalComp, NUMONICS, WACOM.

A digital camera (11) takes images, processes them and stores them in digital format. Instead of film, it uses built-in or removable semiconductor memory to store pictures. It has the same basic features as a normal camera and can also be connected to a computer, TV or printer.

Since the processing of the frame in a digital camera takes place directly in the camera, the user can immediately check the correctness of the received image, print it or send it by e-mail.

The advantages of digital cameras include:

1) The image is processed immediately. Most digital cameras have a small color screen on which you can immediately see the picture that was taken. This allows you to abandon the unsuccessful frame and write in its place another.

2) The images are stored in electronic memory, the cycles of recording and erasing information in which can be repeated almost endlessly. There is no need to buy film, reagents for its development every time.

3) The process of entering photos into a computer has been simplified. Now there is no need to scan custom-made photographs. You simply connect your digital camera to your PC and transfer the images you want to your hard drive.

4) The digital camera allows for a lot of photo manipulation.

1) Low resolution. To date, only professional digital cameras with a cost that makes them inaccessible to the mass user have an acceptable resolution for high-quality printing (over 300 dpi).

2) High, in comparison with conventional cameras of the same class, price.

3) Really high-quality printing of digital photos requires, most often, special equipment and has a high cost price due to expensive consumables.

The principle of operation of a digital camera is as follows (12). A beam of light rays from the subject, passing through the lens (or lens system) of the objective and the diaphragm, enters the CCD (Charged Coupled Device) matrix. The CCD matrix or, as it is also called, the CCD (light-to-signal converter) is a rectangular matrix of light-sensitive elements. A beam of light striking the sensing element is converted into an analog electrical signal. Analog signals from the CCD are converted to digital, processed and stored in memory. Conversion of signals into digital form is carried out using an analog-to-digital converter ADC.

Diagram illustrating the principle of operation of a digital camera

Designations: 1. a beam of light; 2. body; 3. lens; 4. diaphragm; 5.CCD matrix

In addition to CCD, ADC and memory, the digital camera’s electrical circuit includes a DSP processor, which generates an image from digital streams, and a JPEG converter, which compresses images to increase the number of stored frames.

Removable memory is used in digital cameras to increase the number of stored frames and, most often, it is a Flash memory card.

Currently, dozens of well-known manufacturers of both traditional photographic equipment and materials (Kodak, Konica, Nikon, Fuji, Agfa, Olympus, etc.) and computer peripherals and other electronic equipment (Hewlett-Packard, Seiko Epson, Sony. Ricoh, Mustek, UMAX, LG Electronics, Minolta, etc.).

To get the full benefit of using scanners and digital cameras in Windows, you need to install them correctly. Many modern devices do not require additional installation. If you connect and enable them, the system will automatically detect the new device and install the necessary drivers. However, sometimes the automatic device discovery does not work and you have to manually install the hardware.

To install a scanner or digital camera, you need to connect them to your computer, turn on and boot Windows. Next, select the main menu command Control Panel, and the folder of the same name will be opened. Click on the icon named Scanners and cameras. This folder describes how to connect an imaging device to your computer. Studopedia.Org. 2014-2021 year. Studopedia is not the author of the materials that are posted. But it provides the possibility of free use (0.005 s).

Input and Output Peripheral Devices (page 1 of 3)




Peripheral or external devices are devices located outside the system unit and involved at a certain stage of information processing. First of all. these are devices for fixing the output results: printers, plotters, modems, scanners, etc. The concept of “peripheral devices” is rather arbitrary. These include, for example, a CD-ROM drive, if it is made in the form of an independent unit and is connected with a special cable to the external connector of the system unit. Conversely, the modem can be internal, that is, it can be designed as an expansion card, and then there is no reason to class it as a peripheral device. The term “peripherals” refers to devices that connect a computer to the outside world. The list of peripherals that make the computer “a thing for us” is virtually unlimited. Monitors are often mistakenly referred to here as well. Peripheral devices are also called external devices. Second definition of the periphery. these are devices through which information can either be entered into a computer or can be output from it.

Peripheral devices can be divided into:

Basic, without which the work of a computer is almost impossible;

Others, which are connected if necessary;

The main devices include cursor control devices and partly modems (for terminals and diskless stations). Almost any device that can generate and / or control electrical signals can be connected to the PC. Peripheral devices are connected to a computer through external interfaces or using specialized adapters or controllers. The means of connecting any device and any computer bus is an adapter and a controller. The terms “Adapter” and “Controller” are not synonymous! The controller serves the same purposes of pairing, but it has independent actions (after receiving commands from the program serving it). A complex controller can also have its own processor.

The interaction of programs with peripheral devices (more precisely, with a program with adapters) occurs through instructions for accessing I / O ports using interrupts, direct memory access and direct bus control. The exchange can be initiated by either a program or a peripheral device. The program waits for some event in the device (for example, setting the ready bit), periodically reading its status register. This is known as a polled readiness exchange. Interrupts (or hardware interrupts) provide data exchange only with the participation of the processor, etc. this is very CPU intensive. There are four sources of interrupts: internal processor and coprocessor interrupts, non-maskable external interrupts, masked external interrupts, software-called interrupts. Direct Memory Access or DMA (Direct Memory Access). a method of exchanging data between a peripheral device and memory almost without the participation of a processor. In this mode, the processor initializes the DMA controller. sets the starting address, counter and exchange mode, after which it is released. The exchange itself is made by the controller. A complex solution is also possible. polling the readiness of devices (polling) by periodic interrupts, for example, from the system timer. The device for which readiness was detected. serviced, not finished. skips until next interrupt.

Input peripherals

The keyboard is the main input device for the PC. This is the first of the external input devices that the user encounters.

From the time of the appearance of the personal computer until very recently, the appearance and structure of the keyboard remained practically unchanged.

In 1995, after the release of Windows 95, the usual 101-key devices were replaced by keyboards with 104 keys.

Three new keys have been added specifically to implement some of the features of the OS.

A number of changes were associated with ergonomic indicators, that is, with the need for new keyboards to meet modern medical requirements. It was noticed that with daily intensive work with old flat keyboards, “computer operators” began to develop an occupational disease of the hands. Therefore, many new, “ergonomic” keyboards of the most bizarre shapes have now appeared on the market: as if “broken” in two, curved, equipped with hand rests, etc.

and more popular are keyboards with infrared rays, which do not require a cord to connect to the system unit. Signals from such a keyboard are transmitted according to the principle of similar (remote) control.

The most important change, however, did not affect the device or the shape of the keyboard. her role in the PC has changed. Today the range of responsibilities of the keyboard is almost entirely limited to entering text and numbers. And all the functions of control, issuing commands with the arrival of the graphical interface are successfully performed by the mouse.

When you press any key on the keyboard, a miniature switch is triggered, the signal from which is monitored by a special microprocessor, which sends appropriate messages to the computer, where they are processed by the operating system.

The keys on the keyboard can be divided into blocks. Most keys are used to enter letters, numbers, various symbols and punctuation marks. the main group of symbols. Twelve function keys: from to. have a special purpose, depending on the specific program.

An additional keyboard is located on the right. It is intended both for entering numbers and for duplicating the cursor keys. If a key is pressed (indicator is on), numbers are entered. When you press this key again, the indicator goes out, and the additional keyboard duplicates the control keys.

Let’s take a closer look at the service keys using a table example.

Key nameKey function
Esc (Escape)Usually serves to cancel an action or to exit the program.
EnterServes to complete the input of a line and go to the next line, accept a positive answer to a question, etc.
TabDesigned to form indents in the text, switch between various alternatives in dialogs.
ShiftShift key. If you press this key and, without releasing it, press the key with a letter, then a capital letter will be entered. In addition, some keys (such as number keys) have two characters. A simple key press enters the character indicated on the key below. Pressing with a key enters the character shown at the top. For convenience, the keyboard has two keys. As a rule, they are identical, although in some programs they may have different functions.
CapsLockFixed case switching to uppercase mode. Indicator is on.
CtrlControl key, expands the capabilities of the keyboard. Used in combination with other keys. Which key you need to press for a particular command depends on the specific program.
AltAlternative control key. Its purpose is similar to a key. however, they are not identical. Key combinations and key combinations. usually run different programs.
BackspaceErases the last entered character or character to the left of the cursor.
Insert (shorthand:)Serves to switch modes of insertion / replacement of symbols when editing text, to add a new item to the list.
Delete (shorthand:)Serves to delete something, for example, a selected piece of text, a character to the right of the cursor, a list item, etc.
HomeIt is intended to go to the beginning (of a line, a list, etc.)
EndIt is intended to go to the end (of a line, a list, etc.)
PageUp (shorthand:

Especially for working with Microsoft Windows 95/98/2000 / NT4 / XP, two keys for calling the system menu with the image of the Windows logo and a key for calling the context menu with the image of the menu appeared on the keyboard.

Presentation for the lesson “Input Devices in PC

Description of the presentation for individual slides:

GAOU SPO Kaluga College of Information Technologies and Management “Information Input Devices” Lecturer: Alexandrova V.V. Kaluga, 2014

Contents 1. Introduction 2. Input peripherals 3. Conclusion 4. References 5. Appendices

1 Introduction Input devices, or peripheral devices, are those devices through which information can be entered into a computer. Their main purpose. implement impact on the machine

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2 Peripheral input devices

Keyboard The keyboard is the main input device for the PC. This is the first external input device that a user encounters.

Manipulators Various manipulators are used to control the operation of modern programs. Manipulators carry out direct input of information, pointing with the cursor-pointer on the monitor screen, the command or the place of data entry

mouse A mouse is a device designed to provide the convenience of working with modern software

Joystick The joystick is a control stick and is most commonly used in computer games. Joysticks control cursor movements on the screen

trackball A trackball (trackball) is a ball located along with buttons on the surface of the keyboard (upside down mouse).

Touch input devices Such devices are also called tactile, since information is entered into them by touching the light-sensitive surface of the device.

Touch pad It is a mouse pad without a mouse. In this case, the cursor is controlled by a simple movement of your finger on the mat.

Light pen Has a light-sensitive element at its tip. The touch of the pen with the screen closes the electrical circuit and determines the place of data entry or correction.

Digitizer graphic tablet. allows you to create or copy drawings.

Scanners These devices convert the image into digital form for further processing by a computer or display on a monitor screen.

Other input devices The fleet of peripheral devices is very diverse and is constantly expanding with the development of computing technology.

Digital video camera Input device that transmits dynamic video to a computer in real time.

digital, video, camera, used, enter

Microphone Input device for sound information: voice or music.

Conclusion In conclusion, I would like to say that the use of peripheral input-output devices is very important when working with a computer. And absolutely everyone can learn to work and become an experienced user on a PC, this requires a desire and time.

References 1) E.S. Kutugina, D.K. Tutubalin. Informatics. Information Technology. Tomsk 2010 2) N.V. Makarova. Informatics grade 10-11. St. Petersburg 2011 3) 4)

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Pointing (pointing) input devices

Devices through which the direct input of information is carried out by pointing the cursor on the monitor screen of the command or the place of data input With the help of these devices, the user moves the cursor or other program objects across the two-dimensional space of the monitor screen.

Such input devices form a group of manipulators.

Finished works on a similar topic

Touch input devices

They are made in the form of sensitive surfaces covered with a special layer and connected to the sensor. The cursor is set in motion by moving your finger along the surface of the sensor.

Other input devices

Light feather

A kind of manipulators for entering graphic data into a PC. Made in the form of a ballpoint pen or pencil, which is connected with a wire to one of the PC I / O ports.

Data entry consists of touching or drawing lines with a pen along the surface of the monitor screen using a photocell installed at the end of the pen, which registers the change in screen brightness at a point. The light pen is often supplied with a graphics tablet (digitizer).

Used in PCs, engineering and design systems.


A device for converting graphic data (texts, pictures, slides, photographs, drawings) into digital.

They are classified according to the way the reading head and image are moved relative to each other into handheld, roll-to-roll, flatbed and projection. Slide scanners are a type of projection scanners.

Computer steering wheel

A device that simulates a car steering wheel for playing a car simulator (computer game).

System unit

The system unit in the computer is the “master” one. If you carefully unscrew the screws from its back wall, remove the side panel and look inside, then only in appearance its device will seem complicated.

Now I will briefly describe its structure, and then I will characterize the main elements in the most understandable language.

The system unit contains the following elements (not necessarily all at once):

  • microprocessor;
  • mathematical coprocessor;
  • clock pulse generator;
  • memory chips (RAM, ROM, cache memory, CMOS memory)
  • controllers (adapters) of devices: keyboards, disks, etc.
  • sound, video and network cards;
  • timer, etc.

All of them are connected to the motherboard using connectors (slots). We will consider its elements in bold below.

With the power supply unit, everything is clear: it powers the computer with energy. I will only say that the higher its power rating, the steeper.

A hard disk drive (HDD. hard disk drive) is commonly called a hard disk drive.

This nickname arose from the slang name for the first 16KB hard disk drive (IBM, 1973), which had 30 tracks of 30 sectors, coincidentally matching the caliber “30/30” of the famous Winchester hunting rifle. The capacity of this drive is usually measured in gigabytes: from 20 GB (on older computers) to several terabytes (1TB = 1024 GB). The most common hard drive capacity. 250-500 GB. The speed of operations depends on the rotational speed (5400-10000 rpm). Depending on the type of connection between the hard drive and the motherboard, ATA and IDE are distinguished.

A floppy disk drive (FDD) is nothing more than a floppy disk drive. Their standard capacity is 1.44 MB with a diameter of 3.5 “(89 mm). Magnetic materials with special properties are used as a storage medium for magnetic disks, which allow fixing two magnetic states, each of which is assigned binary digits: 0 and one.

Optical disc drives (CD-ROMs) come in a variety of diameters (3.5 “and 5.25”) and capacities. The most common ones are 700 MB. It happens that CDs can be used for recording only 1 time (then they are called R), and it is more profitable to use rewritable RW discs.

DVD originally stood for Digital Video Disk. Despite the name, you can record anything on DVDs. from music to data. Therefore, in recent years, another decoding of this name is increasingly common. Digital Versatile Disk, loosely translated as “digital versatile disk”. The main difference between DVDs and CDs is the amount of information that can be recorded on such a medium. A DVD-disc can be recorded from 4.7 to 13, and even up to 17 Gb. This is achieved in several ways. First, a laser with a shorter wavelength is used to read DVDs than to read CDs, which has significantly increased the recording density. Secondly, the standard provides for the so-called double-layer discs, in which on one side data is recorded in two layers, while one layer is translucent, and the second layer is read “through” the first. This allowed data to be written to both sides of DVDs, thus doubling their capacity, which is sometimes done.

Other additional devices (mouse, printer, scanner, etc.) can also be connected to a personal computer. Connection is made through ports. special connectors on the rear panel.

The ports are parallel (LPT), serial (COM), and universal serial (USB). The serial port transfers information bit by bit (more slowly) over a small number of wires. A mouse and modem are connected to the serial port. On the parallel port, information is transmitted simultaneously over a large number of wires corresponding to the number of bits. A printer and an external hard drive are connected to the parallel port. The USB port is used to connect a wide range of Spectra peripherals from mouse to printer. It is also possible to exchange data between computers.

The main computer devices (processor, RAM, etc.) are located on the motherboard.

Microprocessor (simpler. Processor). the central unit of the PC, designed to control the operation of all units of the machine and to perform arithmetic and logical operations on information.

Its main characteristics are bit depth (the higher it is, the higher the performance of the computer) and clock frequency (largely determines the speed of the computer). The clock frequency indicates how many elementary operations (cycles) the processor performs in one second.
The market respects Intel Pentium processors and its economy version Celeron, and also values ​​their competitors. AMD Athlon with the economy version Duron. Intel processors are characterized by high reliability, low heat generation and compatibility with all software and hardware. And AMD show a higher speed of work with graphics and games, but less reliable.

Computer memory can be internal and external. External memory devices include the already discussed HDD, FDD, CD-ROM, DVD-ROM. Internal memory includes permanent memory (ROM, ROM in English), operational memory (RAM, RAM in English), cache.

ROM is designed to store permanent program and reference information (BIOS. Basic Input-Output System. basic input-output system).

RAM has high speed and is used by the processor for short-term storage of information while the computer is running.

When the power supply is turned off, the information is not saved in RAM. For the normal functioning of a computer these days, it is desirable to have from 1 GB to 3 GB of RAM.

CACHE is a super-fast RAM intermediate memory.

CMOS memory. CMOS RAM (Complementary Metall-Oxide Semiconductor RAM). It stores computer configuration parameters that are checked each time the system is turned on. To change the configuration parameters of the computer, the BIOS contains the computer configuration program. SETUP.

Sound, video and network cards can be either built into the motherboard or external. External boards can always be replaced, whereas if the built-in video card fails, the entire motherboard will have to be replaced. For video cards, I trust ATI Radeon and Nvidia. The higher the memory size of the video card, the better.

Computer device

In this lesson I will tell you about the computer device: what the PC consists of, what function does each of its parts perform.

  • system unit. that large box that stands on your desk or under the desk, on the side of it, etc. It contains all the main components of the computer.
  • peripheral devices. additional components such as a monitor, keyboard, mouse, modem, scanner, etc.

What does computer consist of


The computer keyboard consists of 6 key groups:

  • Alphanumeric;
  • Controls (Enter, Backspace, Ctrl, Alt, Shift, Tab, Esc, Caps Lock, Num Lock, Scroll Lock, Pause, Print Screen);
  • Functional (F1-F12);
  • Numeric keypad;
  • Cursor control (-, Mouse (mechanical, optical). Most programs use two of the three mouse keys. The left key is the main one, it controls the computer. It plays the role of the Enter key. The functions of the right key depend on the program. In the middle there is a scroll wheel, to which you get used to it quickly.

Modem is a network adapter. Can be both external and internal.

The scanner automatically reads from paper and enters into the PC any printed texts and images.

Microphone is used to input sound into the computer.

The monitor (display) is designed to display information on the screen. Most often in modern PCs, SVGA monitors are used with a resolution (the number of dots located horizontally and vertically on the monitor screen) 800600, 1024768, 12801024, 16001200 with up to 16.8 million colors.

Monitor screen sizes range from 15 to 22 inches diagonally, but most commonly 17 inches (35.5 cm). Dot (grain) size. from 0.32 mm to 0.21 mm. The smaller it is, the better.

PCs that are equipped with television monitors (CRTs) are no longer as popular. Of these, preference should be given to monitors with low radiation (Low Radiation). Liquid crystal displays (LCDs) are safer and most computers have such a monitor.

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The printer is designed to print text and graphics. There are dot matrix, inkjet and laser printers. In dot matrix printers, the image is formed from dots in an impact manner. Inkjet printers in the print head instead of needles have thin tubes. nozzles through which the smallest droplets of ink are thrown onto the paper. Inkjet printers also perform color printing by mixing base colors. Advantage. high print quality, disadvantage. danger of ink drying, high cost of consumables.

Electrographic imaging is used in laser printers. The laser is used to create an ultra-thin light beam that traces the contours of an invisible dotted electronic image on the surface of a pre-charged photosensitive drum. After the development of the electronic image with a dye (toner) powder adhering to the discharged areas, printing is performed. the toner is transferred from the drum to the paper and the image is fixed on the paper by warming up the toner until it melts. Laser printers provide the highest quality, fastest printing available. Color laser printers are widely used.

Sound speakers are outputting sound. The sound quality depends. again. on the power of the speakers and the material from which the enclosures are made (preferably wood) and its volume. An important role is played by the presence of a bass reflex (hole on the front panel) and the number of frequency bands (high, middle and low speakers on each speaker).

USB flash drives, in my opinion, have become the most versatile means of transferring information. It is a miniature device in size and weight less than a lighter. It has high mechanical strength, is not afraid of electromagnetic radiation, heat and cold, dust and dirt.

The most sensitive part of the drive is the connector covered with a cap. The sizes of these devices range from 256 MB to 32 GB, which allows you to select the drive of the right capacity, in accordance with the needs. Thanks to the interface, the USB storage device can be connected to any modern computer. It works with Windows 98SE / Me / 2000 / XP / Vista / 7, Mac OS 8.6 operating systems

10.1, Linux 2.4. In Windows, you don’t even need to install any drivers: plugged into a USB port. and work.

A webcam is needed to enter a dynamic image into a computer and sound (for communication and the possibility of creating teleconferences).

An uninterruptible power supply is needed in case of an emergency power outage.

Fuff, well, here, in my opinion, and all the main things that I wanted to tell you about the hardware of the computer, the so-called hardware.

The article “Computer device” was written quite a long time ago. Therefore, if you find an error or find some inaccuracy, please write about it using the comment form. We will be very grateful to you!


Entering information into the computer memory. Keyboard. Key groups.

From the previous lessons, we learned that information is new knowledge that we receive every day, every minute. Each person perceives and processes information using the senses:


  • organs of vision
  • hearing
  • taste
  • touch
  • smell.

For the quick processing of various types of information, a universal machine. a computer. was invented. We call it personal, since a computer has long been available to anyone.

A computer can process information of various types:

  • numerical,
  • text,
  • sound,
  • graphic
  • video information.

Accordingly, the computer receives different types of information from different devices, which we call information input devices.

So, to enter numerical and text information into a computer, a keyboard and a scanner are used.,

a scanner, digital photos and video cameras are used to enter graphic information.

Entering information into computer memory.

Computer science teacher site. Technological maps of lessons, Preparation for the OGE and USE, programming, useful material and much more.


Earlier, we found out that the keyboard is one of the four most important devices of a computer, without it it is impossible to start any computer.

The keyboard of the device for entering information into the computer’s memory contains inside the microcircuit and other parts.

This is the most important part of the computer, it consists of a large number of buttons. there are 104 of them.

Each button on the keyboard can have different properties and perform different functions.

Key groups.

Any keyboard consists of five parts:

Alphanumeric, this part is used to enter letters and numbers, punctuation marks, various symbols.

Small numeric keypad. Serves for a set of numbers and mathematical signs, turns on when you press a button on the block.

Cursor keys and editing.

Function keys F1 to F12. With their help, operations are performed without entering text, commands for different programs. The assignment of the function keys is different.

Special key. used for giving different commands independently and in combination with other keys.

There is also a power control key on the keyboard. power, turns off the computer

sleep, puts the computer to sleep and back

wake, turns on the computer.

Windows key calls the main menu, designed to work with the graphical interface of the Windows operating system.

Let’s consider the purpose of some important keys and key combinations on the keyboard.

Escape. cancels actions or commands, exit the program.

Tab. moves the cursor to the right 8 characters.

Delete. deletes the character to the right of the cursor.

Backspace. erases the character to the left of the cursor.

Caps Lock. enable or disable large letters.

Control shift or alt shift. switch languages.

Home. moves the cursor to the beginning of the line.

End. moves the cursor to the end of the line.

Page Up. go to the previous sheet of the screen.

Page Down. go to the next sheet of the screen.

To enter an uppercase letter, you must first press and hold the Shift key, then press and immediately release the key with the desired letter, and then release Shift.

Sometimes you want all letters to be BIG. For example, heading to text. Then it is enough to press the Caps Lock key and the keyboard switches to another operating mode. Now all letters will be entered in capital letters, pressing this key again will return you to the small letters mode.

If you press a number key while holding down the Shift key, a punctuation mark or special character will appear on the screen. For example, if you press Shift and 1, you get !

This is just a small part of all possible keyboard functions.

Further in the process of work, you can get acquainted with the huge number of keyboard capabilities.

The Enter key has a special meaning. It is called the enter key and is used to enter commands. And also to answer “Yes” to a question from the computer in a dialogue with it, when you need to confirm what the computer asks you about, press this key.

The Enter key is located on the right-hand side of the Shift key on the keyboard, and the Escape key is located in the upper-left corner of the keyboard. It is pressed when it is necessary to cancel a command that the computer has not yet started executing or to stop its execution. You can also use the Escape key to close open menus.

And so, in today’s lesson we remembered that with the help of five receptors a person perceives and processes information: hearing, scent, touch, taste and vision.

A personal computer is a universal machine for receiving, processing and transmitting information.

We learned that a device that we call information input devices serves to enter information into a computer: a scanner, a keyboard, a microphone, a webcam, a digital photo and a video camera.

We got to know the keyboard better and learned that it consists of 104 keys and is an integral part of the computer. We learned the structure of the keyboard 5 main parts:

cursor keys and editing;

It takes a lot of time to fully study the keyboard, all its capabilities, and memorize all key combinations. But further it will be easy and simple for us to work with various types of programs. And we will begin to study the keyboard with a keyboard simulator, where in a playful way we will remember the position of letters and numbers.

A digital video camera is used to enter into a computer

Input and output devices refer to peripheral (additional) devices.

Peripherals. these are all computer devices, except for the processor and internal memory.

Classification of peripheral devices by location (relative to the system unit of a desktop computer or laptop case):

  • internal. located inside the system unit \ laptop case: hard disk (hard drive), built-in floppy drive (disk drive);
  • external. connected to a computer via input-output ports: mouse, printer, etc.

According to another definition, peripherals are called devices that are not included in the computer system unit.

Input and output devices are divided into:

  • Input Devices,
  • output devices,
  • input-output devices.

Classification by type of input information:

  • text input devices: keyboard;
  • graphic information input devices:
  • scanner,
  • digital photo and video camera,
  • WEB-camera. a small digital photo or video camera that takes a photo or records video in real time for further transmission over the Internet;
  • graphic tablet (digitizer). to enter drawings, graphs and plans using a special pencil, which is guided across the tablet screen;
  • sound input devices: microphone;
  • Devices-manipulators (convert hand movement into control information for a computer):

    • non-sensory:
    • mouse,
    • trackball. ball-shaped device, controlled by rotation by hand;
    • trackpoint (Pointing stick). a very small joystick (5 mm) with a rough top, which is located between the keyboard keys, is controlled by pressing a finger;
    • game manipulators: joystick, pedal, steering wheel, dance platform, game console (gamepad, joypad);
  • sensory:
  • touchpad (touch pad). rectangular pad with two buttons, controlled by the movement of the finger and pressing the buttons, used in laptops,
  • touch screen. a screen that reacts to the touch of a finger or stylus (stick with a special tip) is used in tablet personal computers;
  • graphic tablet (digitizer). to enter drawings, diagrams and plans using a special pencil, which is guided across the tablet screen,
  • light pen. device in the form of a pen, data entry by touching or drawing lines on the screen of a CRT monitor (monitor based on a cathode ray tube). The light pen is currently not used.
  • Classification by the type of information displayed:

    • output devices for graphic and text information:
    • monitor. for display (monitor screen),
    • projector. for big screen output,
    • devices for printing:
    • a printer. to display information on paper, as well as on the surface of disks;
    • wide-format printer (“wide” printer). for output on sheets of formats: A0, A1, A2 and A3,
    • plotter (plotter). for displaying vector images (various drawings and diagrams) on paper, cardboard, tracing paper;
    • cutter (cutting plotter). cuts images from film, cardboard along a given contour;
  • audio output (playback) devices:
  • headphones,
  • speakers and acoustic systems (speaker, amplifier),
  • built-in speaker (PC speaker; Beeper). to sound an audible signal in the event of an error.
    • hard disk (hard drive) (included in the drive). for input-output of information on hard disk platters;
    • flash drive (flash drive or USB flash drive). for input-output of information on the memory chip of a flash drive
    • optical drive. for input-output of information on optical disks,
    • floppy disk drive. for input-output of information on floppy disks,
    • streamer. for input-output of information on cartridges (tape media);
    • card reader. for input-output of information to a memory card;
    • multifunctional device (MFP). copier with additional printer (data output) and scanner (data input) functions
    • modem (telephone). for communication of computers through the telephone network;
    • network card (network card or network adapter). for connecting a personal computer to the network and organizing interaction with other network devices (exchange of information over the network).