1.6 Output Devices
Learning Objectives
- Understand the purpose and types of output devices
- Learn about different display technologies (LED, LCD)
- Compare various types of printers and their uses
- Understand common computer ports and their functions
1.6.1 Overview of Output Devices
Output devices are the parts of a computer system that present processed data from the CPU in a human-readable form. They convert digital signals into text, images, sound, or graphics that users can understand.
Examples of Output Devices
Monitor
Displays text, images, and videos
Printer
Produces hard copies of documents
Plotter
Draws high-quality graphics (used in engineering/design)
Speakers & Headphones
Produce sound output
1.6.2 Display Unit: LED and LCD Monitor
Monitor (Visual Display Unit – VDU)
A monitor, also called a Visual Display Unit (VDU), is the most common output device of a computer. It displays processed data as text, images, graphics, and videos on the screen. The output seen on a monitor is known as a soft copy because it is temporary and can only be viewed on screen.
Types of Monitors
Monochrome Monitor
- Displays output in a single color
- Example: Black & white or green & black displays
- Commonly used in older computer systems
Color Monitor
- Displays output in multiple colors
- Standard in modern computing
- Can display millions of colors
LCD Monitor
An LCD monitor is a flat-panel display that uses liquid crystal technology to form images. It consists of two layers of glass or plastic with liquid crystals between them, which align to display text, images, and graphics when activated. LCDs use fluorescent lamps as backlighting.
LED (Light Emitting Diode) Monitor
An LED monitor is a modern flat-panel display that uses light-emitting diodes (LEDs) for backlighting instead of fluorescent lamps used in LCD monitors. They are widely used in computers, TVs, and display devices due to their better brightness, color quality, and energy efficiency.
LCD vs LED Comparison
| Feature | LCD Monitor | LED Monitor |
|---|---|---|
| Backlighting | Fluorescent lamps (CCFL) | Light Emitting Diodes (LED) |
| Power Consumption | Higher | 30-40% less than LCD |
| Picture Quality | Good | Better contrast and brightness |
| Thickness | Thicker | Thinner and lighter |
| Lifespan | 50,000 hours | 100,000+ hours |
1.6.3 Printers: Laser, Ink-jet, Dot-matrix and 3D Printer
Printer Overview
A printer is an output device that produces a hard copy of data or information on paper. Printers are commonly used to print documents, images, and reports from a computer.
Impact Printers
- Print by physically striking ink ribbon on paper
- Slower and noisier
- Can produce carbon copies
- Example: Dot Matrix Printer
Non-Impact Printers
- Do not strike the paper
- Faster and quieter
- Higher print quality
- Examples: Inkjet, Laser, 3D Printers
Laser Printer
- Uses laser beam and toner
- High-speed, high-quality output
- Ideal for offices and businesses
- Lower cost per page than inkjet
Ink-jet Printer
- Sprays tiny ink droplets
- Excellent for color printing
- Affordable initial cost
- Common for home and photo printing
Dot-matrix Printer
- Uses pins to strike ribbon
- Ideal for multi-part forms
- Durable and reliable
- Used in industrial applications
3D Printer
- Creates 3D objects layer by layer
- Used in prototyping and manufacturing
- Works with various materials
- Revolutionizing product design
Speakers
A speaker is an audio output device that converts digital signals into audible sound. It allows users to hear music, voices, alerts, and other audio from a computer or electronic device.
1.6.4 Overview of Ports
Peripheral devices are external hardware components connected to a computer to extend its functions. They allow input, output, storage, and communication, making a computer more useful and user-friendly.
Categories of Peripheral Devices
Input Devices
Keyboard, Mouse, Scanner
Output Devices
Monitor, Printer, Speaker
Storage Devices
Hard disk, Pen drive, SSD
Communication
Modem, Network card
Hardware Ports
Hardware ports are sockets on the exterior of the system unit that allow connection between the computer and external devices. They serve as interfaces for data transfer, communication, and power supply.
Key Functions of Hardware Ports
- Connecting peripheral devices (e.g., mouse, keyboard, printer, pen drive)
- Supplying electrical power to low-power devices
- Transmitting data to and from external devices
USB/Type-C Port
- Versions: USB 2.0 (480 Mbps), USB 3.0 (5 Gbps), USB-C (10-40 Gbps)
- Uses: Data transfer, charging, connecting peripherals
- Features: Reversible connector (Type-C), supports video/audio, fast charging
HDMI (High Definition Multimedia Interface)
- Purpose: Transmits high-definition audio and video
- Versions: HDMI 1.4 (4K @ 30Hz), HDMI 2.1 (8K @ 60Hz)
- Uses: Monitors, TVs, projectors, gaming consoles
VGA (Video Graphics Array)
- Type: Analog video interface
- Max Resolution: 2048×1536 @ 85Hz
- Status: Legacy, being phased out in favor of digital interfaces
Ethernet (RJ-45)
- Speeds: 10/100/1000/10000 Mbps
- Uses: Wired network connections
- Advantages: More stable and secure than Wi-Fi
Audio Jack (3.5mm)
- Types: TRS (stereo), TRRS (with mic)
- Uses: Headphones, speakers, microphones
- Status: Being replaced by USB-C and wireless in newer devices
Interactive Activity
Match the output device with its correct description:
Summary
- Output devices present processed data in human-readable form, including visual, audio, and physical outputs.
- Display technologies like LED and LCD monitors provide visual output with different characteristics in terms of power consumption, contrast, and image quality.
- Printers vary from laser (fast, high-volume) to inkjet (high-quality color) to dot-matrix (impact printing for forms) and 3D printers (additive manufacturing).
- Computer ports like USB/Type-C, HDMI, VGA, Ethernet, and audio jacks enable connection of various output and input devices to computers.
- Modern interfaces like USB-C and wireless technologies are gradually replacing older port standards.