Output device

Computers use tools to share info.

These tools are called output devices.

A screen shows us pictures and words.

A projector can show images on a wall. This is how movies work.

Speakers make sound for us to hear.

You can use headphones to listen alone. This keeps things quiet for others.

Printers put words on paper. Some use ink to make images. Others use heat to make receipts.

Some tools even let you feel things. They use shakes to send a message. These tools help us use computers.

Computers hold lots of data. An output device is a piece of hardware. It changes that data into things humans can sense.

Screens are common output devices. They show us text and images. Most screens use pixels to make a picture. Pixels are tiny dots of light.

A projector is another way to see images. It uses a bright lamp to shine pictures onto a surface. This is how we watch movies.

Sound is another way to get info. Speakers use a part called a driver to make sound.

You can use headphones to listen quietly. A sound card helps the computer send audio to the speakers.

Printers put data on physical items like paper. Inkjet printers spray tiny drops of ink. Laser printers use a laser and toner. Thermal printers use heat to make ink appear. This is how stores print receipts.

Some tools use touch. A Braille display uses raised pins for reading. Haptic technology uses vibrations to let you feel things. This helps people play video games.

An output device is a special piece of computer hardware. It takes information from a computer and changes it into a form that humans can sense.

This could be something you see, like a picture. It could be something you hear, like music. It can even be something you feel through touch. Some devices even turn data into physical things. For example, a printer puts text on paper. In big factories, output devices might even control machines like looms.

These devices help us understand what a computer is doing.

Display screens are the most common type of output device. They work by lighting up tiny dots called pixels. These pixels are arranged in rows and columns.

To make an image, a Graphics Processing Unit, or GPU, works hard. The GPU forms an image on a part called a framebuffer. Then, it sends a signal through a controller. This signal travels through a connection like HDMI or DisplayPort. This happens many times every second to keep the picture smooth. Some screens refresh at 60, 75, 120, or even 144 Hz.

Computers have used different ways to show information over time. Long ago, people used teleprinters to get results on paper. Later, they used computer terminals. These terminals often used a character-oriented display called a VDU.

Most of these early screens were monochromatic, meaning they only had one color. From the 1960s through the 1980s, green screens were very common. These used a special green phosphor to show text. Today, we use much more advanced flat panel displays like LCD or OLED.

Sound is another important way computers share data. A sound card acts as the bridge between the computer and the audio.

Speakers use a part called a driver to make sound waves. You might use large speakers for surround sound. You might also use small headphones to listen quietly. Some computers even have a simple built-in PC speaker. This small speaker makes beeping sounds to help find errors when a computer starts up.

This helps the computer talk to you even without a screen.

We can also use touch to receive information from a computer. Haptic technology uses vibrations to create a sense of touch.

This was first used in game controllers in the late 1990s. Now, it is used in cars and even aircraft systems. For people who are visually impaired, a Braille display is very helpful. It uses tiny pins that rise up out of holes. These pins create the bumps used in Braille reading. This allows people to feel the characters instead of seeing them.

An output device is a piece of computer hardware that converts data into a form humans can perceive. This information can be text, graphics, audio, video, or even tactile sensations. Historically, these devices also converted data into physical, machine-readable forms. For example, industrial settings use printers for paper tape or punched cards. These physical outputs can control non-computerized equipment, such as an industrial loom with electrical robotics.

Visual displays are the most common form of output. These devices create images by illuminating a specific configuration of pixels. In a raster display, pixels are organized into a 2-dimensional matrix of rows and columns. To maintain smooth images, these displays refresh many times per second. Consumer devices typically operate at rates of 60, 75, 120, or 144 Hz.

The process of displaying an image involves several specialized components. First, the Central Processing Unit (CPU) interacts with a Graphics Processing Unit (GPU). The GPU is a processor used to form images on a framebuffer. Once the image is ready, the GPU sends it through a video display controller. This controller generates a video signal to be sent through an interface. Common interfaces include HDMI, VGA, DisplayPort, or DVI.

GPUs come in two primary types: discrete and integrated. A discrete graphics card is an external unit, often connected via a PCI Express bus. Older cards may have used AGP or PCI connections. Some mobile computers can even support external cards through Thunderbolt. An integrated GPU is built directly into the CPU die. Display technologies have also evolved significantly over time. Older monitors used Cathode-ray tube (CRT) technology, which fired electrons at a phosphorous coated screen. Modern flat panels use technologies like TFT-LCD, LED-backlit LCD, or OLED.

Color output is managed through specific models and hardware. Monochromatic displays, which show only one color, were common from the 1960s through the 1980s. A common example was the green screen, which used a green "P1" phosphor. Modern color monitors, or RGB monitors, accept three separate signals: red, green, and blue. They implement the RGB color model by using three different phosphors. By activating these phosphors at different intensities, the monitor creates many colors. However, the total number of colors is limited by the video adapter.

Auditory output provides sound through a specialized interface. A sound card acts as the bridge between the computer and the audio device. It can be part of the motherboard, an expansion card, or a desktop unit. Sound is produced by a speaker using an oscillating transducer called a driver. Speakers can connect via analog phone connectors or digital interfaces like SPDIF. Wireless speakers use radio technology, such as Bluetooth, to connect.

Some computers include a simple PC speaker. This built-in component produces square waves to emit beeps during the Power-on self-test. This helps identify errors during the boot process even without a video display.

Printing devices output data onto physical media like paper. Inkjet printers work by injecting tiny droplets of ink through nozzles. Laser printers use a laser to charge a drum of toner to mark the paper. Thermal printers use heat on sensitive paper, which is common for retail receipts. Other types include dot matrix printers that use impact, and plotters that draw lines with pens.

Finally, tactile technology allows humans to feel computer data. Haptic technology uses vibration and motion to induce a sense of touch. This was introduced in the late 1990s for video game controllers. Today, haptics are used in cars, aircraft simulations, and mobile devices. For the visually impaired, a refreshable Braille display uses pins that rise from holes. These pins create tactile characters that can be read by touch.