Lesson 2: Computer Components

What are the different parts in a computer? At a high level, all computers are made up of a processor (CPU), memory, and input/output devices.

Now let’s see what is inside a computer.

Central processing unit

The central processing unit (CPU) can be called the brain of the computer. It contains all the circuitry needed to process input, store data, and output results. It follows instructions from computer programs about how to process data.

A CPU consists of two main components:

• The arithmetic logic unit (ALU) performs calculations and makes logical decisions.
• The control unit (CU) decides how to interpret program instructions.

What is a computer program?

It is software, which is a collection of code installed in your computer’s hard drive.

Example: A video game is software and it needs CPU, memory, hard drive, and a video card to work (all of which are hardware).

Memory is used to store binary information and transfer it to CPU for further processing.

Let’s say we ask the computer to add 1 and 2. It completes the following process:

• Store 1 (001 in binary) and 2 (010 in binary) in memory.
• Use a circuit in the CPU to calculate the result
• Store the result, 3 (011 in binary), in memory.

The CPU and memory are connected using a high-speed communication system called the memory bus. Only the instructions that are needed for the program that is currently running are stored in memory, where they can be accessed quickly.

Memory types

Random access memory (RAM) is used for the temporary storage of data.

A hard disk drive (HDD) is used for the long-term storage of data. It is also known as secondary memory.

A motherboard is the main circuit board in a computer that holds all components together and allows them to communicate with one another.

Typically, microprocessor, main memory, and other essential components are connected directly. Other devices such as external storage, controllers, and peripheral devices are attached to the motherboard via a plug-in card or cables.

A power supply unit (PSU) is a hardware device that is used to convert mains alternating current (AC) to regulated, low-voltage direct current (DC) for internal components.

It is also used to provide cooling for the computer through PSU fans by circulating air.

A graphics card is a hardware device used to produce the images that are shown in your screen. It is responsible for rendering an image to your monitor. It does this by converting data into a signal that your monitor can understand.

An inside view of a Raspberry Pi microcomputer:

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