Output Unit:
It is used to connect the internal system of a computer with the external environment. It gives the results of any computation or instructions to the outside world in the desired format (information into human-readable form). It can be in form of text, graphics, audio and video files.
Some of the output devices are: Monitor, Printer, Plotter, Speaker, Projector, Headphone, etc.,
(a) Monitor
(b) Projector
(c) Printer
(d) Microphone
(e) Speaker
(f) Plotter
(a) Monitor:
A computer monitor is an output device that is used to display the information in the form of alphabets, numbers, pictures, animations and videos. Monitor looks like a TV screen. It generally contains the visual display, circuitry, casing, and power supply.
Monitors are classified into two types,
  1. Cathode Ray Tube Monitors (CRT)
  2. Thin Film Transistor Monitors (TFT)
In modern computers, Thin Film Transistor (TFT) monitors are used because of their size (Less space) and the ability to dissipate less heat compared to Cathode Ray Tube (CRT) monitors.
(b) Projector:
A projector is an output device which is used to project an image or video onto a bigger surface, such as a white screen or wall. Nowadays, it has been used as an alternative to a computer monitor or television screen when showing videos or images to a large group of people.
These projectors are commonly used in classrooms, conference rooms, auditoriums, and places of worship.
(c) Printer:
A printer is an output device used to print the paper documents such as texts, images, or both.  The output produced by a printer is called a hard copy, which is the physical version of an electronic document.

Depending on the working and construction, printers are classified into two types,
  1. Impact Printers - Dot Matrix Printer, Line Printer
  2. Non-impact printers - Inkjet Printer, Laser Printer
(d) Headphone:
Headphones are similar to the speakers but small in size, and we can wear them in or around our ears. Conventional headphones contain two ear cups jointed by a band that is placed over your head. Smaller headphones, generally called earbuds or earphones are placed inside of the ear canal's outer part.
Headphones contain transducers which are used to convert an audio signal into sound waves. If the headphones are connected to an analog audio port (such as a 3.5 mm audio jack), it processes analog audio signal. Suppose the headphones are connected to a digital port, such as USB; In that case, headphones must need a digital-to-analog converter (DAC), which helps to convert the digital signal into an analog signal.
(e) Speaker:
Speaker is an output device that is commonly used with computer systems. Speakers convert the electromagnetic waves from a computer into sound waves that the listener can hear.
(f) Plotter:
Plotter is an output device used to draw point-to-point lines directly from vector graphics files. It was the first computer output device that could print graphics as well as accommodate full-size engineering and architectural drawings.