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Computer Input and Output Devices and Troubleshooting
Jul 17, 2024
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
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