Computer output devices get information out of the computer, delivering data that has been processed by the computer to you, the user. Output devices produce data in different forms including audio, visual and hard copy. Computer output devices are all peripheral hardware connected to a computer using cables or wireless networking.
The most common computer output device is the monitor or computer screen. Monitors create a visual display for you to view from processed data. They come in a variety of screen sizes and visual resolutions. There are two common types of modern computer monitors, cathode ray tube and flat panel screens. CRT monitors use phosphorescent dots to create the pixels that make up displayed images. Flat panel monitors usually use liquid crystals or plasma to create output. Light is passed through liquid crystals to create the pixels. All monitors rely on a video card that is located on the computer motherboard or in a special expansion slot. The video card processes the computer data into image details that the monitors can display.
Printers produce a hard copy version of processed data such as documents and photographs. The computer sends the image data to the printer, which then physically recreates the image, usually on paper. There are three types of computer printers: ink jet, laser and dot matrix. Inkjet printers spray tiny dots of ink on a surface to create an image. Laser printers use toner drums that roll through magnetised pigment and then transfer the pigment to a surface. Dot matrix printers, common in the 1980s and 1990s, use a print head to embed images on a surface, using an ink ribbon.
Computers produce audio data that requires output devices such as speakers and headphones to deliver the sound to you. Audio data is created by the computer and then sent to the audio card, which is located in an expansion slot. The card translates the data into audio signals, which are sent to the audio output device.
Projectors are display devices that project a computer-created image. The computer sends the image data to its video card, which then sends the video image to the projector. They are typically used for presentations or for viewing videos.
Plotters create a hard copy of a digitally rendered design. The design is sent to the plotter via a graphics card and creates the design using a pen. Generally used with engineering applications, plotters basically draw an image using a series of straight lines.
CD and DVD drives, USB drives, hard disk drives and floppy disk drives are known as input/output, or I/O, devices. They are not only output devices, but are also used as storage and input devices. The computer sends data to the drive, where it is stored and can be later retrieved. CDs and DVDs are both types of optical discs that stores data in a digital format. Data is placed on the disc, using a laser writer that embeds the data into the disc’s coating. A floppy disk is a magnetic storage device. A layer of magnetised material is placed within a proactive plastic casing. The computer embeds the data into the magnetised material, using a writing head.