An output unit, also known as an output device, is any piece of computer hardware that converts information or data into a human-perceptible form or, historically, into a physical machine-readable form for use with other non-computerized equipment. Output devices can be used to display output visually on a computer screen, produce sound through a speaker, or make a hard copy of anything shown on the monitor using a printer. Some common examples of output devices include:

• Monitor or display screen
• Printer
• Speaker or headphones
• Projector
• Plotter
• Braille embosser or reader
• Global Positioning System (GPS)
• 3D printer

Output devices work by receiving a signal from the computer and using that signal to perform a task to display the output. For example, when you type "H" on a computer keyboard (input device), the computer processes the input and sends a signal to a monitor (output device) to display the "H" on the screen. Without an output device, you wouldnt be able to determine what the computer is doing or view the results of input from a computer.