Computer Hardware Components & Classes Explained

Any computer system is made up of two components namely the computer hardware and computer software. Both hardware and software work together to run a computer.

In this article, we focus on computer hardware. In particular, we will cover what is computer hardware, examples of computer hardware, and various classifications of computer hardware.

What is Computer Hardware

Computer hardware refers to the physical components of a computer. In other words, computer hardware is a collection of all tangible components of a computer that are either internal or external.

Examples of external hardware components include the keyboard, mouse, and screen. Internal hardware includes CPU, RAM, Network Interface Cards, and Motherboard among others. 

Classification of Computer Hardware Components

Since there are many computer hardware components, we classify them into categories easily understand.

In this article, we will discuss computer hardware classification into two broad classes. The two classes are classification by functions and Fundamental or basic computer hardware parts. Let’s start with classification by functions.

Computer Hardware Components Classification by Functions

Hardware is classified into Storage Devices, Input Devices, Output Devices, and Processor devices.

1). Computer Input hardware Parts

  • Audio Devices – microphone and keyboard
  • Bluetooth Devices- Keyboard, mouse, handset, printer, and gamepad
  • Gaming Devices –Steering wheel, gamepad, and Joysticks
  • Network Devices- Ethernet devices and Bluetooth devices
  • Pointing devices – Mouse, touchpad, touchscreens, motion sensors, interact whiteboard, fingerprint scanner.
  • Visual devices – webcam, camcorder, biometric scanner, barcode reader

2). Computer Output Hardware Parts

For the data we feed in computers to be useful to us, we need to retrieve the processed information. To do so, the computer uses output devices to deliver information to us. The output may be either soft copy or hard copy.

A soft copy refers to output that is not tangible. Examples include images videos, audios, and touchscreens. Soft Copies hardware include:

  • Visual: Monitor/projector, interactive whiteboard
  • Sound: Speakers, earphones, and headphones
  • Network: Ethernet cables, Bluetooth devices

Hard copies are tangible computer output. The most popular hard copy is the printouts we print from the printer. Hardcopies computer hardware components include:

  • Impact printers: Dot matrix printers and 3D printers
  • Non-impact printers: inkjet, LaserJet, thermal printers

3). Computer Processors Hardware Components

Computer processing converts raw data from input devices into information that a computer can understand.

For us to understand the information, the computer needs to process information into a version we can understand. For instance, if we may need a graph from a given data, the computer needs to plot a graph using excel.

The computer processor is referred to as the microprocessor popularly known as the CPU. Here is a complete review of the CPU.

4). Computer Storage Hardware

The computer must store data to operate. For instance, for a computer to operate, it requires an operating system (OS) which maybe Windows and Linux.

That OS must be stored somewhere for the computer to use it to power on. Thus, the computer must have storage hardware. The storage devices are classified into primary and secondary storage.

Primary Vs secondary computer memory

Primary memories are those memories that are found within a computer system. Examples of primary memories are RAM or ROM. RAM is further devised into SRAM and SRAM.

Secondary Memory is memory devices that we can plug and play to act as additional memory space for computer systems.

Common examples are the hard disk drive (HDD), Solid-state disk (SSD), floppy disks, and hard disks.

Computer Hardware Classification By Necessity

In this classification, we are concerned with how necessary is certain computer hardware for the computer to functions

We ask ourselves one question in this classification. Is specific computer hardware necessary for the computer to operate?

Computer hardware may be classified into either fundamental hardware components or peripheral hardware components according to necessity.

Computer hardware that must be necessary for a computer to operate are classified as the fundamental computer hardware components.

Whereas, those that must not be for a computer to operate are classified as peripheral hardware parts.

Fundamental/Basic Computer Hardware

These are computer hardware that a computer cannot function without. In other words, a computer requires this hardware to operate.

The 8 Fundamental hardware include Computer Case, CPU, Hard Drive, Graphics Card, MotherBoard, RAM, Power Supply Unit, and Cooling unit.

Let’s see the function of each of these hardware components.

  1. The Computer Case: A case is a computer house. It is a plastic or a metallic box that houses the rest of the computer components.

The case is specially made to accommodate all other components including those connecting from outside.

Therefore, you will find the case with space to allow other components to connect. Other computer components are mounted to the case using screws.

  1. Power Supply Unit (PSU): PSU is a combination of the AC to DC converter and the charging unit that we plug into the power sockets.

A PSU provides electricity to power computer components. PSU does so by converting AC current to DC current.

  1. Motherboard: The motherboard is the circuit board of a computer. It provides mounting to various components inside the computer case.

The board enable different components to send electrical signals to one another depending on the instructions provided

Thus, a motherboard holds various components together and enables them to communicate.

The main components of a motherboard include an integrated circuit (IC), transistors, diodes, connecting wires, and printed boards.

  1. CPU (Central Processing Unit): A CPU is a unit that processes instructions and controls data flow within the computer. Therefore, all data and instructions you input in a computer are processed from in the CPU.

For this reason, a CPU is commonly referred to as the brain of the computer. The CPU has three main components. They include the Arithmetic and Logic Unit, a control unit, and the Memory unit. Read all the details about CPU here. 

  1. Computer Hard Drive: The hard drive is the computer store. That’s why the hard drive is also commonly referred to as computer Storage.

All saved data including videos, pictures, documents, and music among others are stored here. Therefore, when you copy a movie from a friend you usually save it at the hard drive.

Common hard disk sizes in the market include 80GB, 120GB, 200GB, 500GB, and 1TB. It is advisable to buy a computer with large hard drive space.

The hard drive can run out of space depending on how much you save in it. A common warning is a computer you are running low in your disk space.

If this happens, do not panic. You can upgrade your hard drive say from 80 GB t0 500GB by buying and replacing a 500GB hard drive.

However, the hard drive is very slow in accessing the files and delivering them to the CPU for processing. Such is undesirable.

For instance, you cannot wish to wait for a minute for a word document to open. Or for two minutes for a movie to open. Obviously, it is undesirable.

It is for this reason that a computer has a Random Access Memory (RAM) discussed below.

  1. Random Access Memory (RAM): A RAM is a computer memory that temporarily stores data and instructions that are currently in use. RAM commonly referred to as computer memory.

The memory differs from the hard drive in that it is faster to access data. Instead of a computer, accessing files every time like in hard drive, the CPU fetches the instructions and stores in the RAM.

Therefore, RAM helps the CPU to access files faster thus increasing the processing speed of a computer. How does this happen? When you launch a program, the CPU identifies the files required to run the program in the hard drive.

The CPU then pulls these files from the Hard drive to the RAM. As we have said before, the CPU can then quickly access them from the RAM

This makes the program run faster termed as high processing speed. Therefore, the higher the RAM, the higher the processing speed. However, RAM is a volatile memory. By this, it means whenever the power goes off, the memory is erased.

If you have a computer with a small RAM, you can upgrade your RAM say from 4GB to 8GB or 16GB to give your computer faster processing speeds. Read more about computer RAM, its function, and how it works here. 

  1. Graphics Card and the Monitor: You have stored your video in the hard drive. You have the right RAM to quickly load it to the CPU for processing.

Your motherboard can display the video on the screen. However, the video quality will not be very good. It is, for this reason, we have a Graphics card in computers.

A graphics card works in conjunction with the computer screen A graphics card simply determines the color intensity of various parts of the picture or videos.

  1. The Cooling System: Various computer components explained above emit heat while in operation. Also, various components in a computer can only operate within a specific temperature range

Therefore, if the temperature goes beyond the range your computer will switch off to protect the components. To prevent such from occurring, computers have a cooling system. The cooling system is made of heat sink bars and a fan.

The bars conduct heat away from the components hence cooling their environment. Similarly, a fan constantly rotates to pump hot air away and cold air to the components.

The combination of the two ensures the internal temperature of the computer is conducive for components to operate optimally.

When you switch on your computer and it goes off after a minute or so. Most likely your fan has malfunctioned. The computer is turning off due to overheating

 Peripherals Computer Hardware Parts

These are computer parts that a computer can function without. Such hardware components are meant to make a computer easier to use.

They include the input devices and output devices are the oldest peripheral hardware. However, technological advancement has seen the introduction of expansion cards.

Below is a comprehensive summary of the common peripheral hardware.

Input Devices: These are devices that we use to input data to the computer. Examples include keyboard, mouse, joystick, and touch screen. Trackball and touchpad among others.

Output Devices: These devices present data out of the computer to the user. Examples include a microphone, headphones, or a speaker.

Computer Expansion Cards: A Bluetooth adapter is a USB device designed to receive and transmit Bluetooth signals wirelessly. The adapter is plugged to any USB ports on your computer. A good example is a network interface card.

Network Interface Card (NIC): NIC is a hardware component that connects a computer to a network source. We usually connect our computer to the internet source through an RJ45 Ethernet cable.

Are you aware that the port through which we plug the Ethernet cable is part of the NIC? If not, now you know.

Different NIC cards support different internet speeds. Popular speeds include 10mbps, 100mbps, and 1Gbps, up to a maximum of 160Gbps.


Computer hardware is the physical components of computer systems. Computer hardware is classified either according to the functions or by fundamentals hardware.

Hardware classes according to functions include input hardware, output hardware, computer processor, and storage hardware devices.

Hardware classes by fundamental computer parts include the Computer Case, CPU, Hard Drive, Graphics Card, Motherboard, RAM, Power Supply Unit, and Cooling unit.


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