Lecture on Computer Input and Output Devices

Input Devices

Keyboard

• Basic input device for a computer
• Composed of keys: alphabets, numbers, and symbols
• Used for word processing, writing emails, browsing web pages
• Connector types:
  • Older 6 pin D connector (obsolete)
  • USB connector (modern)
  • D to USB adapters allow for use on both connection types

Mouse

• Pointing device
• Moves cursor on screen corresponding to physical movement
• Uses:
  • Starting applications
  • File and folder management
• Typical structure:
  • 1 button (Macintosh)
  • At least 2 buttons (Windows)

Digital Camera

• Takes digital photos and videos
• Stores images on internal hard drive or SD card
• Transfer data to computer via USB cable or SD card

Barcode Reader

• Reads barcodes using light scanning
• Utilized in point of sales, inventory management
• Connection types:
  • Serial port
  • USB port
  • Wireless
• Forms: Handheld trigger type (most popular)

Scanner

• Creates digital copies of physical documents/photos
• Structures:
  • Flatbed scanner
  • Combination scanner/printer
• Process: Place document face down, scan, save image to computer

Touch Screen

• LCD monitor with input detection system
• Detects touch as mouse clicks
• Used in:
  • All-in-one computers
  • Tablets (e.g. iPad)
  • Touch-based phones

Webcam

• Captures video/images for video conferencing/calls
• Typically connects via USB
• Often includes built-in microphone
• Major manufacturers: Logitech, Microsoft

Media Card Reader

• Reads memory cards from devices like cameras
• Basic structure: USB cable connected to reader body containing slots
• Card types: Micro SD, Mini SD

Docking Station

• Allows laptop to function like a desktop
• Connects laptop to external monitor, keyboard, mouse, printer, etc.
• Specific to manufacturer (no universal fit)

KVM Switch

• Controls multiple computers from a single monitor, keyboard, and mouse
• Features: Selectable buttons for switching control to different computers
• Sizes range:
  • Controls 2 computers (low-end)
  • Controls up to 8 computers (high-end)

Smart TV

• Connects to internet
• Functions: Web browsing, streaming movies/TV shows, video messaging
• Often includes webcam and microphone for video calls

Smart Card

• Used for personal identification
• Structure: Size of credit card, embedded microprocessor chip
• Reader: Accepts and reads smart cards

Biometric Device

• Uses unique physical traits (e.g., fingerprint scanner) for identification
• Commonly integrated into laptops and smartphones

Motion Sensor

• Detects hand movements without physical contact
• Typically connects to a computer via USB cable

Digitizer

• Converts analog hand movement (drawing) into digital format
• Structure: Flat surface tablet and stylus
• Connects via USB cable

Game Controllers (Game Pads/Joysticks)

• Used for gaming systems (e.g., Xbox, PlayStation)
• Can connect to PC via USB

Output Devices

Computer Monitor

• Primary output component
• Connection: Video adapter through monitor cable (VGA, DVI, HDMI, DisplayPort)
• CRT (Cathode Ray Tube): Older, bulky, uses electron guns for color
  • Refresh rate: Measured in hertz, higher rate reduces eye discomfort
  • Requires degaussing to remove unwanted magnetic fields
• LCD (Liquid Crystal Display): Modern, flat panel using liquid crystals
  • Technologies:
    • TFT (Thin Film Transistor): Higher quality image
    • TN (Twisted Pneumatic): Older, cheaper, poorer color/viewing angles
    • IPS (In-Plane Switching): Better color/viewing angles, higher power consumption
  • Backlighting: Fluorescent lamps or LEDs
• Resolution: Number of pixels (higher resolution = clearer image)
  • XGA: 1028x768
  • SXGA: 1280x1024
  • SXGA+: 1400x1050
  • UXGA: 1600x1200
  • WUXGA: 1920x1200
• Contrast ratio: Contrast between black and white

Printer

• Connects via USB or network (Ethernet/Wireless)
• Types:
  • Inkjet: Common for home use, produces high-quality, photo-like results
    • Issues: Ink smudging, streaks, faded prints
  • Laser: Uses toner, higher quality prints
    • Issues: Ghosting (faint images appearing), drum/fuser wear
  • Thermal: Uses heat to print on thermal paper
  • Dot Matrix: Impact printer, outdated but durable and used for multi-copy documents
• Virtual Printing: Saves digital copies
  • Print to File: Saves in ready-to-print format
  • Print to PDF: Universal, readable across devices

Hard Disk Drive (HDD)

• Primary permanent storage
• Structure: Sealed case with magnetic disks
• Speeds: 5400, 7200, 10000 RPM
• Interface: Serial ATA (SATA), faster than old parallel ATA
• Advantages: Hot-swappable, smaller cables

Solid State Drive (SSD)

• No moving parts, uses flash memory chips
• Fast data transfer speeds

Hybrid Drive

• Combines magnetic disks and flash memory (SSD)
• Magnetic disks for storage, flash memory for caching

Removable Storage

• Types:
  • Tape drive: Backups, sequential data storage
  • CD/DVD-ROM: Optical drives, reading/writing capabilities
  • Blue-ray: High-capacity optical storage
  • Thumb drives: USB, portable storage
  • Secure Digital (SD) cards: Used in cameras, various sizes (Micro, Mini)
  • Compact Flash: Used in DSLR cameras
  • XD Picture cards: Older, proprietary
• EMMC: Embedded Multimedia Controller, internal memory for smartphones/tablets
• Hot spare: Swap without powering off
• Cold spare: Requires power-off to replace

Troubleshooting Mobile Devices (Common Issues)

• Touchscreen unresponsive: Restart device, eject/reinsert SIM, perform hard reset
• App performance issues: Close background apps, restart device
• GPS issues: Ensure GPS is on, check external factors (weather, obstacles)

Troubleshooting Laptops (Common Issues)

• No display: Connect to external monitor to check
• Dim display: Replace inverter
• Battery issues: Could be battery or motherboard, replace as needed
• Power issues: Verify charger connection, could indicate dead motherboard
• Flickering monitor: Check LCD or inverter
• Keyboard problems: Check for physical obstructions, replace keyboard if necessary
• Ghost cursor: Disable tap feature on touchpad, update touchpad drivers
• Overheating: Clean air vents and fans, ensure laptop on flat surface
  • Cooling issues: Check air circulation, clean dust
• Wireless issues: Check for interference, update wireless network card drivers

Additional Topics Covered

• Power Supply: Converts 110v AC to specific voltages for PC; different connectors (P1, P4, Molex, SATA, Berg, 6-pin)
• Motherboard: Main circuit board with processor socket, memory slots, bus slots; form factors (ATX, micro-ATX, BTX, ITX, NLX)
• BIOS: Basic Input Output System, initializes peripherals, settings storage
• CMOS: Chip maintaining settings, battery-powered
• POST: Power On Self Test, ensures hardware functioning
• UEFI: Unified Extensible Firmware Interface, modern BIOS with better features
• RAID: Fault tolerance system (0, 1, 5, 10)
• Cables and Connectors: Various types and uses (RJ-11, RJ-45, BNC, F-type, IEEE 1394, USB, Thunderbolt, RCA, fiber optic related: ST, LC, SC)
• Plenum: Fire-resistant cabling for buildings with airflow spaces