Computer Peripherals, Interfaces, and Technologies

Posted on Nov 15, 2024 in Technology

1. Definition and Types of Peripherals

Peripherals are devices through which a computer communicates with the outside world. They also serve as storage systems, acting as auxiliary memory. Peripherals facilitate input/output (I/O) operations, complementing the CPU’s processing. They are classified into five main categories:

  • Input Peripherals: Capture and send data to the computer for processing.
  • Output Peripherals: Display or project information from the computer. These devices convert electrical impulses into human-readable information.
  • Input/Output Peripherals (I/O): Both introduce data into the computer and receive processed information.
  • Storage Peripherals: Store data and information persistently, unlike volatile RAM.
  • Communication Peripherals: Enable communication with other machines for collaboration or data exchange.

2. Webcam

A webcam is a small digital camera connected to a computer that captures and transmits images, often live, over the internet. Some webcams are autonomous, requiring only network access. Software captures frames from the camera and sends them to be displayed. For video, a rate of 15 to 30 frames per second is ideal. Webcams consist of a lens, an image sensor, and processing circuitry.

3. Scanner

A scanner converts printed images into digital format using light. They often include features like automatic document feeders or transparency adapters. Digital images can be edited, cropped, or converted to text using OCR. Scanner types include:

  • Flatbed: The document is placed on a glass surface, and a moving arm scans the image.
  • Orbital: Used for delicate or valuable documents, capturing images with a mounted camera.
  • Drum: Offers high-resolution scans (up to 4,000 dpi) but is slow and unsuitable for fragile documents.
  • Handheld: Manually drawn across the image, requiring a steady hand for optimal results.

4. Scanner Quality

Scanner quality depends on color depth (24-bit or 48-bit), resolution (DPI), and density range. High density range allows for better shadow and highlight reproduction. Scanning can be done in grayscale or color, with many scanners offering duplex capabilities. Advanced scanners use firmware to clean up scans and compress data. OCR technology converts scanned documents into editable files, often using ISIS and TWAIN drivers to create TIFF files.

5. Digital-to-Analog Converter and Digitization

An analog-to-digital converter (ADC) converts analog signals into digital data. It uses reference voltages (Vref+ and Vref-) to determine the conversion rate. Resolution depends on the maximum input value and the number of output bits. Digitization involves periodically measuring the amplitude of an analog signal, rounding it to a quantization level, and storing it as an integer.

6. Touchscreen

A touchscreen is both an input and output device. It allows users to interact directly with the display, providing a more intuitive and efficient interface. Touchscreens are common in industrial settings and interactive exhibits.

7. Graphics Card

A graphics card processes data from the CPU and converts it into visual information for display. The GPU (Graphics Processing Unit) is a dedicated processor optimized for floating-point operations used in 3D graphics. Video memory (VRAM) stores graphical data, ranging from 128 MB to 1 GB. The Z-Buffer manages depth coordinates in 3D images.

8. Graphics APIs and Effects

Graphics APIs abstract the complexities of graphics cards. Two major APIs are:

  • Direct3D: Developed by Microsoft for Windows.
  • OpenGL: A free, open-source, and multiplatform API.

Common graphical effects include:

  • Antialiasing: Smooths jagged edges in curves and lines.
  • Shader: Processes pixels and vertices for lighting and other effects.
  • HDR: Represents a wide range of light intensities.
  • Texture Mapping: Adds detail to surfaces.
  • Motion Blur: Simulates the blurring of moving objects.
  • Depth Blur: Blurs objects based on distance.
  • Lens Flare: Imitates light reflections in a camera lens.
  • Fresnel Effect: Adjusts reflections based on viewing angle.

9. Monitors

Monitors display information generated by the computer. Common types include:

  • CRT (Cathode Ray Tube): Uses an electron gun to illuminate phosphor on the screen.
  • LCD (Liquid Crystal Display): Uses liquid crystals to control light transmission.
  • TFT-LCD (Thin-Film Transistor LCD): A type of active matrix LCD with improved image quality.
  • Plasma: Uses gas-filled cells to produce light.
  • OLED (Organic Light-Emitting Diode): Uses organic compounds that emit light when stimulated electrically.

10. Sound Card

A sound card handles audio input and output. Quality depends on the card’s capabilities, not whether it’s internal or external. External sound cards often offer higher quality and performance.

11. Sound Card Specifications

Sound cards use a digital-to-analog converter (DAC) to convert digital audio to analog signals. Common specifications include:

  • Bit Depth: Determines the dynamic range of the audio (e.g., 16-bit).
  • Sample Rate: Measured in kHz, determines the audio frequency range (e.g., 44.1 kHz, 48 kHz).

12. Hard Disk Structure

Hard disks consist of:

  • Platter: Individual disks inside the drive.
  • Head: Reads and writes data to the platters.
  • Track: Concentric circles on a platter.
  • Cylinder: A set of tracks aligned vertically across multiple platters.
  • Sector: Divisions of a track, typically 512 bytes.

Internal components include:

  • Master Boot Record (MBR): Contains the partition table.
  • Partitions: Logical divisions of the disk for different file systems.

13. Hard Drive Interfaces

Common hard drive interfaces include:

  • IDE (Integrated Drive Electronics): An older standard with limited transfer rates.
  • EIDE (Enhanced IDE): Improved IDE with increased capacity and transfer rates.
  • SATA (Serial ATA): A faster and more efficient serial interface.
  • SCSI (Small Computer System Interface): A high-performance interface often used in professional environments.

14. CD Burning

A CD-R is burned by melting its surface with a laser. Pits and lands are created to represent data, which is read by a CD player. Burning a pit requires a temperature of around 250°C.

15. CD, DVD, and Blu-ray Differences

These optical media differ in laser wavelength and storage capacity:

  • CD: Uses an infrared laser (780 nm).
  • DVD: Uses a red laser (635 nm or 650 nm).
  • Blu-ray: Uses a blue laser (405 nm).

16. Flash Memory

Flash memory is a type of EEPROM that allows multiple memory locations to be erased or written simultaneously. It’s commonly used in portable devices due to its speed and low power consumption.

17. Modem

A modem converts digital signals to analog signals for transmission over telephone lines. The process is called modulation-demodulation.

18. ADSL Modem

An ADSL modem is a type of DSL modem that provides high-speed internet access over existing telephone lines.

19. Network Card

A network card (NIC) enables communication between devices on a network. Common types include Ethernet and wireless (Wi-Fi) cards.

20. Bluetooth Card

A Bluetooth card adds Bluetooth connectivity to a PC, allowing communication with Bluetooth devices.