By Elimu Assistant Team 
Table of Contents
Definition of a computer
A computer is a machine that transforms data into information. It can also be defined as an electronic device that stores, transmits, and processes data into useful information.
Common terminologies used in computer
- Data: A collection of numbers and characters that, on their own, do not hold much meaning for the user.
- Information: A sequence of numbers and characters that can be interpreted as meaningful. It is essentially processed data.
- Computer Program: A set of instructions written to perform a specific task using a computer.
- Input Stage: The phase where data is entered into the computer using input devices, such as a keyboard.
- Processing Stage: The phase where data is processed using processing devices, like the CPU.
- Output Stage: The phase where the processed data is displayed by output devices, such as a monitor.
Parts of a computer:
System Unit
- CPU (Central Processing Unit): The brain of the computer, responsible for executing instructions.
- Motherboard: The main circuit board that connects all components and peripherals.
- Drives: Devices like HDDs (Hard Disk Drives) and SSDs (Solid State Drives) are used for storage.
- Cards: Expansion cards such as graphics cards, sound cards, and network cards that add functionality.
Peripheral Devices
- Input Devices: Keyboards, mice, scanners, and webcams.
- Output Devices: Monitors, printers, and speakers.
- Storage Devices: External hard drives, USB flash drives.
- Communication Devices: Modems, network cards.
Connections
- Ports: Sockets on the system unit for connecting cables (USB, HDMI, Ethernet).
- Wireless: Devices using technologies like Bluetooth, Wi-Fi, and infrared to connect without cables.
However, parts of a computer can be summarized as The Mouse, Keyboard, Screen and System Unit (computer chassis)
Definition of peripheral devices
A peripheral device is any extra piece of equipment you connect to a system unit to make it do more things.
Examples of Peripheral Devices
Keyboard: Resembling a typewriter, this input device allows users to enter data into the computer in the form of characters, symbols, and instructions.
Mouse: A pointing device that enables users to interact with the computer. By moving the mouse, the pointer on the screen moves correspondingly, allowing users to click on icons and controls to issue commands.
Monitor: Also known as a screen or visual display unit (VDU), this output device displays what is happening within the system unit, providing a visual interface for the user.
Modem: Derived from the terms modulation (converting digital signals to analogue) and demodulation (converting analogue signals to digital), this device connects the computer to the Internet. It functions as both an input and output device.
Printer: An output device that converts digital documents (softcopy) into physical documents (hardcopy).
Scanner: This input device digitizes physical documents, converting them into digital format for the computer.
External Hard Drive: Used for additional storage, this device can serve as both an input and output device, allowing data to be read from and written to it.
Speakers: Output devices that produce sound from the computer, enhancing the multimedia experience.
Webcam: An input device that captures video and images, often used for video conferencing and streaming.
Microphone: This input device captures audio, allowing users to record sound or communicate via voice.
USB Flash Drive: A portable storage device that can be used to transfer data between computers, functioning as both an input and output device.
Graphics Tablet: An input device that allows users to draw or write on a flat surface, with the input being transferred to the computer screen.
Questions and Answers on the definition and parts of a computer
Why is a computer regarded as an electronic device?
Answer
Computers are regarded as electronic devices because they use electric signals to function.
Identify the following peripheral devices
ANSWERS
- scanner
- webcam
- speaker
- printer
- mouse
- screen
- microphone
- graphic tablet
- flash drive
- external hard drive
- modem
- keyboard
What are peripheral devices?
Answer
These are devices attached to the system unit of a computer for basic or additional functions.
A monitor is also known as?
Answer
Screen or Visual Display Unit (VDU)
A monitor is referred to as VDU because it displays all the happenings in the system unit.
State the four key parts that make up a computer
Answers
- Keyboard
- Mouse
- Screen
- System Unit
Draw a well-labelled diagram showing how data is processed into information and the stages involved.
Answer
What does CPU stand for?
Answer
Central Processing Unit
What is a Modem? What is it used for?
Answers
Modem stands for Modulation and Demodulation. This a device that converts digital signals to analogue for transmission and converts them back to digital at the receiving station.
Data that has been processed and has meaning is referred to as?
Answer
Information
List three stages involved in transforming data.
Answers
- Input
- Processing
- Output
