Your question infers you are unsure of the difference between an input and an output device. It is like asking why an apple is a fruit. Or maybe not because there is a logic behind this query, and I get it. I can’t explain why an apple is not a vegetable the way I can clarify why a projector is an output device. So first, let me define an input device briefly before I get to the output device and projector in particular.
An input device is any hardware that allows us to send data to a computer. So if you type a message on a keyboard or touch a screen to make something happen, you are using an input device. The input devices are the buttons and the sensors for light, temperature, acceleration, and magnetism.
Output device
On the other hand, an output device is any hardware that allows a computer to communicate information. For instance, displaying a message on a screen, playing sound via a speaker or headphones, or printing a document. So if you want to play music on your phone and press play on the touchscreen, you are using an input device to tell your phone to play the music.
The phone will then play the music, and the sound will come through an output device: your headphones. The BBC micro: bit has several built-in input and output devices. In other words, the output devices receive processed information from the central processing unit and present it to the user.
The monitor displays the output from a computer.
Printers print content on paper documents.
Plotters are a type of printer that prints on large sheets.
Projectors display videos, images, or presentations on large screens. Headphones are smaller speakers.
Speakers are used to produce audible output.
Braille reader is used to help visually challenged people to read the text displayed on the computer monitor.
Types of outputs generated by output devices
Output devices generate computer outputs that are of the following two types; Soft copy output-it is temporary because it does not appear on paper or some material that a user can carry for showing to others or for filing and use when he is not using a computer.
Example
For instance, contents displayed on a terminal screen, words spoken by the speaker. Hard copy output-it is permanent because it appears on paper or some material that a user can carry for showing to others or for filing and uses later when not using a computer.
Example
For example, the output produced on paper by printers or plotters. Now see the classification of output devices; we can classify output devices broadly into monitors, printers, plotters, screen image projectors, and speakers (as I already mentioned before).
Hopefully, this answers your question about why a projector is an output device. I mean, if not an output device, it could be only one thing, an input device, and it does not operate that way.
