Unlike input devices like keyboards and mice that let you send data to your computer, you use output devices to receive information back from your computer in a way you can read, see or hear. These devices rely on other computer components like video cards, sound cards, Bluetooth communication or ports, and they may use a wireless or wired connection. For example, you likely use a monitor to see your computer's operating system, programs and data and use speakers to hear sounds and music. Along with sound devices and monitors, other common types of output devices include printers, data projectors and accessibility devices.
Coming in a variety of sizes, shapes and display technologies, monitors work with your computer's video card and show you a real-time picture of your computer's operating system, programs and data so you can properly interact with them. Many computers have built-in or external flat-screen monitors featuring LCD or LED technologies using small diodes that give off light. Other users choose bulkier cathode ray tube (CRT) monitors, which are similar to older TVs and feature a vacuum tube that emits electron beams to show an image. Some monitors can double as input devices if they have a touchscreen you can use in place of a mouse or keyboard.
Headphones and speakers are common examples of output devices for listening to music or other sounds from your computer. Laptops and monitors often have speakers built into them, while headphones and other speaker systems are external devices. Your computer's audio card enables audio data from your computer to travel in a digital signal through a wired or wireless connection to your speakers or headphones. Your sound device then turns that signal into analog sound waves you can actually hear.
Printers and Plotters
Computer printers give you a way to output pictures, text and other information from your computer onto paper. Inkjet printers are especially common for home users and use ink cartridges where little dots of ink are sprayed onto the page to make the image. Dot matrix printers differ in that they use ribbons of ink and have a print head that presses on the paper. Frequently used for mass printing, laser printers use laser beams and toner to make an image by generating electrical charges.
In addition to these traditional printers, 3D printers are available that allow you to create physical objects using plastic filament and specialized computer modeling software. Often used for computer-aided design, there are also large printers called plotters that print detailed graphs and images using a pen.
Data projectors connect to your computer's graphics card and allow you to mirror your computer's screen onto an external surface like a wall or screen. They use mirrors that can split white light into blue, red and green light that will go through a lens to magnify the image. The most common types are LCD and digital light processing (DLP) projectors, with the latter being more expensive and utilizing a color wheel filter. Companies and schools often use these output devices during meetings and classes to let a large group of people follow along with a presentation. Everyday users might use projectors to watch videos on a larger screen to view with friends and family.
Accessibility Output Devices
Other output devices of a computer include tools that help users with visual or hearing impairment to read the screen or hear some sound. Blind users may use a Braille printer to output text onto paper with embossed dots they can feel to read, or they might use special displays that can display lines of text in Braille. While they're not physical tools, screen magnifying software and screen readers can make text larger on a monitor or use a synthesized electronic voice that is easier to understand.