Types of Computers
Before looking at the various components, it is useful to distinguish between two different types of computers: desktop computers and laptop computers. A desktop computer consists of a computer case and a separate monitor, keyboard, and mouse. As the name suggests, this type of computer is typically placed on a desk and is not very portable.
Typical desktop computer with a separate computer case, monitor, keyboard, and mouse
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A laptop computer has the same components but integrated into a single, portable unit.
Typical laptop computer with integrated hardware components
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While these two types of computers look quite different, they have the same general hardware components.
Hardware Components
Let's start with the computer case. This is the metal enclosure that contains many of the other hardware components. It comes in various shapes and sizes, but a typical tower model is between 15-25 inches high. Want to know what's inside? Okay, go get a screwdriver and let's open it up. Seriously, if you are really into computers, the best way to learn is to actually get hands-on. To save us some time, however, have a look at this desktop computer case. A computer enthusiast replaced the metal side panel with a transparent one, so we can have a look inside.
Although that photo looks pretty cool, it is a bit hard to recognize the individual components, especially with all the connecting wires running through it. This figure shows a more schematic version of a desktop computer, which makes it easier to point out the essential hardware components.
The various components of a computer case
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The computer case contains a power supply unit (#6) to convert general-purpose electricity to direct current for the other components. The most critical component is the motherboard (#2), a plastic board on which several essential components are mounted. This includes the central processing unit, or CPU, (#3), the main memory (#4), and expansions slots (#5) for other hardware components. The internal hard disk drive (#8) serves as the mass storage device for data files and software applications. An optical disk drive (#7) makes it possible to read from and write CDs and DVDs. Other hardware components typically found inside the computer case (but not shown in the figure) are a sound card, a video card, and a cooling mechanism, such as a fan.
A computer system also needs input devices, such as a keyboard (#9) and a mouse (#10). To interact with a user, a computer system also needs a display device, such as a monitor (#1).
The hardware components described so far result in a fully functional computer system. A user can provide input using the keyboard and the mouse, and the computer can process instructions, read and write information, and display the results on the monitor. Most present-day computer systems have additional hardware components to provide more functionality. These include input devices, such as a microphone and video camera, and output devices, such as speakers. These can be integrated into the other hardware components or connected as external devices.
Additional peripheral devices can be connected to the computer systems, such as an image scanner to input paper documents as digital files, a printer to print out documents, and an external hard disk drive for extra mass storage.
The hardware components described here are all part of a personal computer. Other types of hardware are needed for a computer network and for the infrastructure that supports the Internet, but those types of hardware are not covered here.
Lesson Summary
Computer hardware is a general term to describe all the physical parts of a computer system. A typical computer system consists of a computer case, a power supply unit, a motherboard, a central processing unit (CPU), main memory, and a hard disk drive. Input devices include a keyboard, mouse, microphone, video camera, and image scanner. Output devices include a monitor, speakers, and a printer.
Learning Outcomes
By the end of this lesson you should be able to:
- Describe computer hardware
- Recall some of the components of a computer system
- List some of the parts of a computer case
