Computer hardware is the tangible, physical infrastructure that enables a computer to work in tandem with computer software. It includes components like the central processing unit, random access memory, computer data storage and input devices like keyboards.
Computer components come in many sizes. Smartphones and tablets, for example, use the same internal hardware as desktop computers, just on a much smaller scale.
Motherboard
Also known as a mainboard, system board or mobo, the motherboard is what holds and connects all of the other computer hardware components. It houses a processor, RAM and other chips wired together with circuits that transfer power and data.
When you turn on your computer, the motherboard reads a firmware chip called the BIOS or UEFI that allows all of the components to recognize each other and start up properly. It then distributes the electric current from a power source to the individual parts of your computer using pre-determined connections.
The motherboard is the center of a computer and acts like the skeleton, nervous system and circulatory system all-in-one. Without it, each part of the computer would need to have its own independent power connection and be at risk from dangerous power fluctuations. It is also where most of the other hardware components connect, such as the CPU, expansion slots and USB ports. Modern motherboards often feature reversible Type-C and Thunderbolt 3 ports.
Video Card
A video card (also called a graphics card or graphics adapter) is a specialized piece of hardware that creates the images that your computer displays on its screen. It contains a graphics processing unit, or GPU, which is a processor that performs graphic calculations; a digital-to-analog converter; and memory chips that store display data.
Like other pieces of hardware, a video card requires a device driver to communicate with the operating system. Drivers are available from the manufacturer or online.
Many high-end video cards allow multiple monitors to be connected simultaneously using different ports, such as HDMI, DisplayPort or DVI, and VGA. These ports provide varying levels of resolution, refresh rate and color depth. Some video cards also include auxiliary power connectors for added performance.
Optical Drive
An optical drive lets your computer read and interact with discs like CDs, DVDs, and Blu-rays. Optical drives were once so common that nearly every new desktop and laptop computer came with one. But nowadays, they are rare to find — a sign that most people prefer to download their data and software from the internet instead of using discs.
The back of an optical drive contains ports for a cable that connects to the motherboard, as well as a connection for power from the power supply. Most optical drives also have jumper settings that let you configure how the motherboard recognizes multiple optical drives if you install more than one.
The center of an optical drive houses the laser lens. A small, black object is just above the laser that contains one to three potentiometers (usually a separate potentiometer for CDs, a second for DVDs, and a third for Blu-ray Discs if supported by the drive) which adjust the intensity of the laser beam.
Computer Case
The computer case, also known as the system unit, is the outer shell that houses all of the other components inside a computer. It also helps protect the hardware from dust and other debris. The case also helps dissipate heat from the CPU and other components, reducing the risk of overheating.
The case is available in different sizes and form factors, making it easy to find a model that fits your motherboard. There are desktop cases that sit flat on a desk and tower cases that stand upright. There are even small form factor cases, or SFFs, that are designed to minimize the size of a desktop computer.
Mid-tower cases are the most common type of PC case. They can accommodate almost all motherboards and are a good choice for most build types. They also have enough room for full-size video cards and allow for extra fans to improve cooling. In addition, they have a number of 5.25-inch and 3.5-inch expansion bays for optical drives, floppy disk drives and hard drives.