Output Devices

An output device is any device used to send data from a computer to another device or user. Most computer data output that is meant for humans is in the form of audio or video. Thus, most output devices used by humans are in these categories. Examples include monitors, projectors, speakers, headphones and printers.  They also include peripherals, which may be used for input/output (I/O) purposes, like network interface cards (NICs), modems, IR ports, RFID systems and wireless networking devices, as well as mechanical output devices, like solenoids, motors and other electromechanical devices.
The most common output devices that are known are; monitor, printer, speaker and projector.

Monitor
The term "monitor" is often used synonymous with "computer screen" or "display." The monitor displays the computer's user interface and open programs, allowing the user to interact with the computer, typically using the keyboard and mouse.
Older computer monitors were built using cathode ray tubes (CRTs), which made them rather heavy and caused them to take up a lot of desk space. Most modern monitors are built using LCD technology and are commonly referred to as flat screen displays. These thin monitors take up much less space than the older CRT displays.

Fig 1.1 CRT

Fig 1.2 LCD

Projector
A projector is an output device that can take images generated by a computer or Blu-ray player and reproduce them onto a screen, wall, or other surface. Typically, the surface projected onto is large, flat, and lightly colored. A projector is used recently to;

• Project a PowerPoint presentation at a business meeting.
• Project a computer screen to teach a class in school.
• Project a TV or computer with a movie playing to a large screen.

Fig 1.3 Projector

Speaker
Speakers are transducers that convert electromagnetic waves into sound waves. The speakers receive audio input from a device such as a computer or an audio receiver. This input may be either in analog or digital form. Analog speakers simply amplify the analog electromagnetic waves into sound waves. Some speakers are designed to work specifically with computers, while others can be hooked up to any type of sound system. Regardless of their design, the purpose of speakers is to produce audio output that can be heard by the listener. 

Fig 1.4 Speaker

Printer

A printer is a device that accepts text and graphic output from a computer and transfers the information to paper, usually to standard size sheets of paper. Personal computer printers can be distinguished as impact or non-impact printers.

Fig 1.5 Printer

Sources

• “What Is an Output Device? - Definition from Techopedia.” Techopedia.com, www.techopedia.com/definition/3538/output-device.
• “Monitor.” Monitor Definition, techterms.com/definition/monitor.
• “Speakers.” Speakers Definition, techterms.com/definition/speakers.
• “What Is a Projector?” Computer Hope, 30 Oct. 2017, www.computerhope.com/jargon/p/projecto.htm. 
• “What Is Printer? - Definition from WhatIs.com.” WhatIs.com, whatis.techtarget.com/definition/printer.