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**Chapter :input and output devices** **Input Devices of Computer:** An input device is a computer device or hardware that allows the user to provide data, input, instructions to the computer system. We have shared the examples of the Input Devices. Input devices Input Devices of Computer Hardwa...

**Chapter :input and output devices** **Input Devices of Computer:** An input device is a computer device or hardware that allows the user to provide data, input, instructions to the computer system. We have shared the examples of the Input Devices. Input devices Input Devices of Computer Hardware devices are used to provide instructions or feed data to computer systems. The instruction or data inserted during this process is called "Input" while the device used to input the data is known as an input device of a computer.  These input devices of a computer can be further divided into different categories such as pointing devices, keyboard devices, drawing devices, recognition devices, etc. Some of the commonly used Input devices are- 1.Keyboard 2.Mouse 3.Joystick 4.Scanner 5.Light Pen 6.Microphone 7.Digital Camera 8.Track Ball 9.Bar Code Reader 10.Optical Character Reader **Examples of Input Devices** Input device helps the user to send data, information, or control signals to a computer system. The Central Processing Unit (CPU) of a computer system receives input and processes it to produce the output. examples of Input Devices. **Keyboard** Keyboards are one of the primary input devices which helps in entering data and commands in a computer or any electronic device by pressing keys. A keyboard has a different set of keys for letters, numbers, functions, and characters. A keyboard is connected to a computer system through a USB cable (for a wired keyboard) or through Bluetooth (for a wireless keyboard). Most of the keyboards are in two sizes, 84 keys or 101/102 keys but nowadays many brands are making keyboards with 104 or 108 keys for Windows. Laptops come with an inbuilt keyboard which makes the laptop smaller and lighter. Whereas most modern devices such as smartphones, tablets, etc come with onscreen virtual keyboards that help to input data into a computer. Before keyboards were discovered, paper tapes and paper cards were used to give instructions to computers.  **Mouse** The mouse is a commonly used input device that helps the user to interact with the computer system through a process called "point and click".  This hand-held input device is used to move cursor or pointer across the screen. It works on a flat surface and has left and right button with a wheel in between to perform the tasks. The left button helps to select items whereas the right button helps to display the menu. The wheel in between helps to scroll the page up and down while surfing or reading documents. Laptops come with an in-built touchpad which serves the purpose of a mouse. You can control the movement of the cursor in a laptop by moving your fingers over the touchpad. Input Devices of Computer: Definition, Functions, Examples and Images\_4.1 **Joystick** A Joystick is also a pointing device like a mouse which is widely used to play games on a computer. Joysticks are made up of a stick with a spherical base wherein the base is fitted in a socket which allows free movement of the stick. The cursor or pointer is controlled on the screen through the movement of the stick. C. B. Mirick invented the first Joystick at the U.S. Naval Research Laboratory. Joysticks are of different types such as displacement Joysticks, finger-operated Joysticks, hand operated, isometric joystick, and more. The major difference between a Joystick and a mouse is that, in joystick, the cursor keeps moving in the direction of the joystick unless it is upright, whereas, in mouse, the cursor moves only when the mouse moves.  **Light Pen** A light pen is an input device of a computer which looks same as a pen. A light pen is a very sensitive device and consists of a photocell and an optical system placed in a small tube. Also the tip of the light pen contains a light-sensitive detector that enables the user to point or select objects on the display screen. These devices are mainly used to select on screen items, draw pictures and write freely in document files using a computer screen. When the tip of the light pen is moved in the computer screen while pressing the button on the pen, corresponding signals are sent to the CPU. The first light pen was invented around 1955 as a part of the Whirlwind project at the Massachusetts Institute of Technology (MIT). Input Devices of Computer: Definition, Functions, Examples and Images\_6.1 **Microphone** The microphone or a "mic" is a type of an input device which helps the user to input voice in a computer system. Mics read sounds from the surroundings and then convert the analog sound waves into electrical signals. The microphone receives the sound vibrations and converts them into audio signals or sends to a recording medium. The audio signals are also converted into digital data and are then stored in the computer. The microphone helps the user to telecommunicate with others. Sounds can be added to presentations and  with webcams for vide conferencing with the help of microphones.  **Scanner** A scanner is an important input device that helps us to convert a hard copy document into a digital file (.jpeg,.png,.pdf, etc). The technology behind Scanner is called Optical technology which basically reads characters or pictures from a paper and transfers them to the computer drive for further processing. A scanned image can further be edited, printed, emailed, etc. Scanners are available in different types that perform different functions. Some common examples of a Scanner are photo scanner, flatbed scanner, drum scanner, sheet- fed scanner, etc. Input Devices of Computer: Definition, Functions, Examples and Images\_8.1 **Digital Camera** Digital cameras are input devices that record images (and sometimes videos) digitally. Instead of using film, digital cameras use an image sensor chip to capture images. The first step in using a digital camera as an input device for computer is to connect it to it. Using a USB cable, a memory card reader, or a wireless connection can accomplish this. Using photo editing software or a file manager, you can transfer the images and videos from the camera to the computer.  **Webcam** A webcam is a video camera that is designed specifically to record or stream to a computer or computer network. The primary objective of a webcam is for live streaming, video conferencing, video telephony, social media, etc. Two types of webcams are used in computers: internal (built-in) and external. Webcam **Output Devices of a Computer** An output device is a hardware component of a computer system that displays information to users. An output device is a computer hardware device that retrieves and presents the result of the inserted input data from the computer system and further translates that data into human-understandable language. **Examples of Output Devices are**- Monitor Printer Speakers Headphones Projector GPS Plotter **Monitor** The most general example of an output device is a monitor. It is also known as a Visual Display Unit (VDU) and the major function of a monitor is to display the processed data like images, videos, text, audio, etc. A monitor arranges the microscopic dots known as pixels in a rectangular pattern to make images. The number of pixels present determines the sharpness of an image. Monitors are further classified into two types- cathode-ray tubes and flat panel displays. **Cathode Ray Tube**: Cathode Ray Tube Monitors use cathode ray tubes that help to produce images in the form of video signals on the screen. In short, CRT generates a beam of electrons with the help of electron guns that strike the inner surface of the phosphorescent of the screen to generate images. The CRT monitor holds millions of phosphorus dotes in three different colors, i.e., red, blue, and green. The sharpness and quality of the picture depend on the number and size of these pixels. **Flat Panel Display**:  A flat-panel display uses liquid crystal technology or plasma to generate output. In such devices, light is passed through liquid crystals to form pixels. Flat Panel Displays have lesser volume, weight, and power consumption than a CRT. They can be put on the wrist or could be hung on the wall. Some examples of flat-panel displays are calculators, video games, monitors, laptop computers, and graphical displays **Printer** Printers are another common example of Output devices. Printers primarily operate by producing a copy, typically a hard copy or Xerox copy, of the information transmitted by the computer. The printer receives electronic data from the computers and produces a hard copy of the processed data. Printers are divided into two categories which are Impact Printer and Non-Impact Printer. 1**) Impact Printer**: In impact printers firstly the characters are printed on the ribbon which is then smashed on the paper. In other words, we can say that Impact Printers uses a print head or hammer to print the data on paper. The hammer or print head strikes an ink ribbon against the paper and the character starts printing the paper. Some examples of impact printers are: **Dot matrix printer** **Daisy wheel printer** **Line printer** **Chain printer** 2\) **Non-Impact Printers**: Non-impact printers do not use any hammer or print head to strike the ink ribbon. These printers print characters or images without using ribbons. Non-Impact printers are often known as Page Printers because they print one full page at a time. Some examples of non-impact printers are: **Laser printer** **Inkjet printer** printer Projector The projector is an output device that receives images from a computer and allows users to project their output onto a large area, such as a screen or a wall. The computer first sends the signal to a video card which then transmits the signal to the projector to project the images on the surface. Projectors magnify texts, photos, and movies using light and lenses. As a result, it's an excellent output device for giving presentations or teaching big groups of people. **Characteristics of Projector:** Projectors are lightweight and can be easily connected and hung on the wall. Projectors can be the most cost-effective option for large-screen video in your home. A small projector mounted on a back shelf or bookcase, or mounted on the ceiling, takes up no area on the floor. It is barely visible when it is not in use. **Speakers** Speakers are the output devices that are connected to computers to allow sound to be output. For the working of speakers, sound cards send signals to the speakers which are converted into audio. Speakers are available in a variety of shapes and sizes ranging from simple two-speaker output devices to surround-sound multi-channel sets. These speakers use internal amplifiers which vibrate at different frequencies to increase/decrease the volume or amplitude of sound**.** **Characteristics of Speakers:** **Speakers are available in a wide range of qualities and prices.** **Small, plastic computer speakers with low sound quality are often included with computer systems.** **They come in a variety of sizes so can also be easily carried around** **Headphones** Headphones are the output devices that help us listen to the audio coming out of a computer. With the help of headphones, we can listen to the audio privately and without disturbing anyone around. These come in various sizes and brands and can be connected with computer systems both wired or wirelessly. Computers generate sound or audio as electric signals, which we perceive through headphones. The headphones can convert electrical energy into mechanical energy and we can then listen to songs or audio on computer systems. Headphones are light and portable, unlike heavy computer speakers**.**