1.3.1 Input Devices

Input devices are used to provide data to the computer system, enabling interaction between the user and the machine. Common input devices include:

• Keyboard: The primary device for text entry, allowing users to input letters, numbers, and symbols.
• Mouse: A hand-held device used to control the cursor and interact with the computer interface. It typically features buttons for selection and navigation.
• Microphone: Captures audio input, converting sound waves into electrical signals for processing by the computer.
• Scanner: Captures images from physical documents and converts them into digital formats for storage, editing, or display.
• Barcode Reader: Reads barcodes printed on products to retrieve product information such as code, description, and price, useful in retail environments.
• Digital Camera: Captures images in digital format, which can be transferred to a computer for editing or storage.
• Touch Screen: A display that responds to touch inputs, allowing users to interact directly with what is displayed on the screen. Common in mobile devices and tablets.

1.3.2 System Unit

The system unit is the central component of a computer, housing essential hardware elements. It includes:

• Motherboard: The main circuit board, containing the microprocessor, main memory, expansion cards, and connectors. It facilitates communication between various components.
• Microprocessor (CPU): The central processing unit, responsible for executing instructions. It contains:
  • Control Unit (CU): Directs operations within the CPU.
  • Arithmetic Logic Unit (ALU): Performs arithmetic and logical operations.
  • Registers: Small storage locations for temporary data.

Expansion Slots:

Slots on the motherboard for adding expansion cards.

RAM Memory Slots:

Slots for installing RAM.

Socket for Microprocessor:

Holds the CPU.

Ports:

For connecting input and output devices.

1.3.3 Storage Devices

Storage devices are used to save data and programs for long-term use. They include:

• Hard Disk: A magnetic storage device with a high storage capacity, used for permanent data storage.
• Compact Disk (CD): An optical storage medium with a capacity of about 700 MB, used for storing data, music, and software.
• Digital Versatile Disk (DVD): Similar in size to a CD but with greater storage capacity (4 to 16 GB), used for storing larger files and multimedia.
• Memory Card: A small, portable storage device with capacities ranging from a few GBs, used in laptops, cameras, and mobile devices.
• USB Flash Drive: A small, portable storage device connected via USB, with capacities up to 128 GB, used for transferring and storing data.

1.3.4 Output Devices

Output devices display or produce information from the computer. They include:

• Monitor: Displays visual output. Types include:
  • CRT Monitor: Older technology, now largely obsolete.
  • LED Monitor: Slim, energy-efficient, and offers better display quality.
• Printer: Produces hard copies of text and images. Types include:
  • Impact Printer: Uses mechanical impact to print, e.g., dot matrix printers. Known for noise and lower print quality.
  • Non-Impact Printer: Includes inkjet and laser printers. Inkjet printers use ink cartridges, while laser printers use toner and are faster with higher print quality.
• Plotter: Used for printing large-format graphics such as architectural blueprints and maps. Includes ink plotters and pen plotters.
• Speaker: Produces audio output, commonly used for multimedia applications and sound playback.