Input and output Devices of Computer

Input and output devices enable the computer to interact with the external world. User Can enter data and instructions into the computer with the help of input devices. Whereas After processing the data, it sends the results back to the output devices. The input can In a variety of forms e.g. text, image, voice, etc. Similarly, the output may be required in Forms depending upon the user’s requirements. That’s why a number of different input and output devices are available.

Input Devices

The input devices are those that fulfill the function of entering or providing data and control signals to the central processing unit of a system. In most cases, we talk about input devices for devices that have a connection to the central unit of a computer, that is, the CPU. As stated, the central function of computers is the processing of data, so it can be said that the history of computing itself is the history of the improvement of processing methods: Starting in 1970, in what is known as the fourth generation of computers, the most important innovation was microprocessors (or chips), which generated a revolution in matters of data processing: the speed of processing increases 770,000 instructions per second. The computer could be made much smaller, accessible to homes, and much less expensive. Since 1985, innovation in computers has been concentrated mainly on the input through sound waves with wireless systems, as well as through the emergence of robotics: cybernetics is progressing faster and the interconnections between computers demand the introduction of methods each time. more efficient for data entry and processing. The fundamental division between devices, then, is made according to their function with respect to processing:

  • Input devices: They provide information to the computer for processing.
  • Output devices: They are important for the reproduction and presentation of information to users.

In any case, there are some cases of mixed or hybrid devices, which at the same time send and receive signals to different parts of the computer: the latest generation of devices such as the touch screen, mouse, or scanner are examples of this.

Examples of input devices

1. Stylus: A pointing device that is applied on the screen.
2. Mouse: Functional device to move around the computer screen.
3. Touch screen: Screen designed to recognize the pressure on the surface. By touching the screen, the user can make a selection or move the cursor, equivalent to the mouse.
4. Scanner: Device that, with a light beam, detects light and dark patterns and thus allows converting a physical image into a digital signal that reproduces it as it is.
5. Joystick: A pointing device that is used very frequently in computer games, although it is also frequent in industrial applications to operate devices.
6. Bar code reader: By means of the laser, it is possible to read drawings formed by bars and parallel spaces, thus encoding information.
7. Alphanumeric keyboard: The most frequent, with 62 keys including all the numbers and letters, in addition to a series of commands.
8. Function keyboard: Useful for computer systems, it has 13 configurable letters.
9. Digital photo camera: Connects to the computer and transmits the images it captures. It can be a photo or video.
10. Webcam: Like the camera but small, not showing the images it takes, but simply transmitting them to the computer.

Output devices

The output devices are those devices that give computers the indispensable role of communicating information to the user after being processed by it.

The presentation of the data after being processed, in any of its forms, is carried out by this class of devices that will be much more useful the more they can make the presentation of the work simple and practical.

The output devices, together with the input devices, constitute the group of peripherals that give computers real utility. At the same time that data processing systems evolved over time, these peripherals were endowed with greater technological advances, reaching today to allow the use of computers to people just a few years old, when, remember, The first computers were designed to be used only by people who knew perfectly the commands and the circuits that were in it. It can help you:

  • Input devices

Examples of output devices


In the output devices, there is one par excellence, whose example perfectly synthesizes the history of this class of devices: the monitor. Through a graphics card, the computer and the peripheral are connected, allowing the image of the processing that is being carried out on the computer to be observed on the monitor, and through this image, the user can have a notion of what he is actually doing. The first monitors emerged in the early ’80s and were monochromatic, only showing texts. The following monitors, CGA and EGA, gradually adapted to the support of colors and graphics, and also increased the pixel resolutions. VGA monitors, created in 1987 by the IBM company, were essential in order to incorporate a quantity of video memory, making the previous models obsolete. The most recent time in the history of monitors has caused them to be divided into two classes, according to the way the image is represented: CRTs are those that use cathode rays, drawing an image that sweeps the electrical signal, while LCDs use a liquid crystal through substances that share the properties of solids and liquids at the same time.


The device through which the computer lets out sounds. They exist for both table and ear, commonly known as headphones. The functionality is the same and the volume can be regulated from the computer.


Peripheral used to present information on paper. It is the ideal complement to all the text or graphics procedures that the PC has since the printer is the one that takes all that work to the dimension of physical objects, beyond the computer.


Graphics plotter, functional for technical drawing, or architecture tools.


Using some programs, the projectors can enlarge the monitor image and make it visible to large groups of people.


Although they are not peripheral devices, and they are not only output devices (since it simultaneously works as an input device), in fact, the information processed by the PC can be carried there.

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