PC Components

Welcome to the realm of PC components, where the digital magic of your computer unfolds. This comprehensive guide will illuminate the intricate universe of CPUs, GPUs, motherboards, RAM, and more. Whether you’re a seasoned enthusiast or a novice, understanding these vital elements is your passport to harnessing the full potential of your machine. From decoding the CPU’s processing prowess to unlocking the GPU’s graphic brilliance, this article will demystify the world of PC hardware, ensuring you make informed choices for your computing needs. Join us on this journey into the heart of your computer, where knowledge empowers your tech dreams.

Basic Functional Diagram of PC

Casing and System Unit

In the context of personal computers (PCs), “PC casing” and “system unit” often refer to the same physical component, which is the enclosure that houses the core components of a computer. However, there can be a slight distinction in the terms:

  1. PC Casing: “PC casing” is a more colloquial or informal term used to describe the outer shell or case that contains the internal components of a computer. It’s essentially the physical shell or housing that surrounds the computer’s hardware. A PC casing can come in various designs, sizes, and materials, often chosen for aesthetics or functional purposes. It provides physical protection to the internal components and typically has openings for cooling fans and ports for connecting peripherals.
  2. System Unit: “System unit” is a more technical term used to describe the enclosure that houses the core components of a computer, excluding peripherals like the monitor, keyboard, and mouse. It specifically refers to the central component enclosure where the motherboard, CPU, RAM, storage drives, power supply unit, and other essential components are located. The system unit is a critical part of a PC and plays a vital role in the computer’s functionality and organization.

In summary, while both terms are often used interchangeably to describe the housing of a computer’s internal components, “PC casing” tends to be a more casual term, while “system unit” is a more technical term that emphasizes the core components’ organization and function within the enclosure. Regardless of the term used, this component is essential for protecting, cooling, and connecting the internal components of a PC.

Flat Casing
Mid Tower Casing
Tower Casing

Inside System Unit

The PC system unit, also known as the computer case or tower, houses several critical components that make up a personal computer. Here is a list of the primary components you can find inside a typical PC system unit:

  1. Motherboard: The main circuit board that connects and holds various components like the CPU, RAM, and expansion cards. It serves as the central hub for data transfer and power distribution.
  2. Central Processing Unit (CPU): The computer’s brain, responsible for executing instructions and performing calculations.
  3. Random Access Memory (RAM): Temporary memory that allows the CPU to store and access data quickly for running applications and tasks.
  4. Graphics Processing Unit (GPU): Handles graphics rendering and acceleration, critical for video games, multimedia, and graphical applications.
  5. Storage Drives: Various types of storage, including Hard Disk Drives (HDDs) and Solid-State Drives (SSDs), where data is stored. These drives hold the operating system, software, and user files.
  6. Power Supply Unit (PSU): Supplies electrical power to all components within the system unit. It converts electricity from the wall outlet into voltages required by the computer’s components.
  7. Cooling System: Fans, heatsinks, and in some cases, liquid cooling systems to dissipate heat generated by the CPU, GPU, and other components to prevent overheating.
  8. Optical Drive (optional): A CD/DVD/Blu-ray drive for reading and writing optical discs (less common in modern PCs due to digital distribution).
  9. Expansion Cards: PCIe cards such as dedicated sound cards, network interface cards (NICs), or additional graphics cards for added functionality.
  10. Cables and Wiring: Power cables, data cables, and connectors that link components to the motherboard and power supply.
  11. Front Panel Connectors: Ports and buttons on the front of the case, including USB ports, audio jacks, power buttons, and LEDs.
  12. Case Fans: Additional fans that promote airflow to cool internal components effectively.
  13. Mounting Hardware: Screws, brackets, and other hardware used to secure and organize components within the case.
  14. Drive Bays: Spaces for mounting storage drives, including 3.5-inch and 2.5-inch drive bays.
  15. Expansion Slots: PCIe slots for adding graphics cards, network cards, sound cards, and other expansion cards.
  16. Cable Management: Features like cable routing channels and tie-down points to keep internal wiring neat and organized.
  17. Dust Filters: Mesh or filters to prevent dust from entering the case and clogging fans and components.

These components collectively make up the heart of a personal computer. The specific configuration and components can vary based on the type of computer (e.g., gaming PC, workstation, server) and individual preferences. Building or upgrading a PC often involves selecting and installing these components within the system unit to create a functional computer system.

Inside System Unit

The motherboard is the main interfacing component of the computer that brings all other components under the central interface.


The processor is the main processing device of the computer which is connected to the motherboard through a socket.


RAM is an active memory device that temporarily stores inputted and processed data.

Harddisks are used as permanent storage devices of computers.

Internal Cards

Internal cards increase the various processing capabilities of the PC. These are basically assistive devices.

The power supply unit provides power to the various parts of the computer.

Power Supply Unit

PC motherboard and its components

A PC motherboard, also known as a mainboard or system board, is a critical component that connects and integrates various hardware components within a computer. Here are the primary components found on a typical PC motherboard:

  1. CPU Socket: The central processing unit (CPU) socket is where the computer’s processor is installed. Different sockets support various CPU types and generations.
  2. RAM Slots: These slots hold the computer’s memory modules, such as DDR4 or DDR5 RAM. The number of slots and supported RAM capacity vary by motherboard.
  3. Expansion Slots: PCIe (Peripheral Component Interconnect Express) slots allow for the installation of expansion cards like graphics cards, sound cards, and network cards.
  4. Chipset: The chipset is a collection of integrated circuits responsible for controlling various motherboard functions, such as communication between components, data transfer, and power management.
  5. BIOS/UEFI Chip: The Basic Input/Output System (BIOS) or Unified Extensible Firmware Interface (UEFI) chip stores the firmware that initializes and manages hardware during the boot process.
  6. SATA Ports: Serial ATA (SATA) ports connect storage drives like hard disk drives (HDDs) and solid-state drives (SSDs) to the motherboard.
  7. M.2 Slots: M.2 slots provide support for high-speed NVMe SSDs, offering faster storage performance compared to traditional SATA drives.
  8. USB Headers: These connectors allow for additional USB ports, such as front-panel USB ports on the PC case.
  9. Power Connectors: The motherboard features power connectors for the CPU (often 8-pin or 4-pin) and the main ATX power connector (usually 24-pin).
  10. I/O Ports: Rear I/O ports provide connections for USB devices, audio equipment, video outputs (e.g., HDMI, DisplayPort), Ethernet, and other peripherals.
  11. CMOS Battery: A small battery on the motherboard powers the CMOS (Complementary Metal-Oxide-Semiconductor) chip, which stores BIOS settings and system time.
  12. Header Connectors: These connectors allow for the attachment of front-panel buttons and LEDs (e.g., power button, reset button, HDD activity LED) from the PC case.
  13. Network Controller: Often integrated into the motherboard’s chipset, the network controller manages wired or wireless network connections.
  14. Audio Controller: Integrated audio components provide sound output and may include audio jacks, capacitors, and audio processing circuitry.
  15. Voltage Regulators: These components ensure stable power delivery to the CPU, RAM, and other critical components.
  16. Debug LEDs: Some motherboards have diagnostic LEDs that display error codes to aid in troubleshooting hardware issues.
  17. Heat Sinks and Fans: To dissipate heat generated by the CPU and chipset, motherboards may feature heat sinks and fan headers for cooling.

Motherboards come in various form factors (e.g., ATX, microATX, mini-ITX), each with a different size and set of features. The choice of motherboard depends on factors such as the CPU type, expansion needs, and case compatibility.

PC Motherboard
Desktop PC Motherboard

Outside System Unit

The outside of the PC system unit includes various components and features that allow users to interact with and access the internal hardware. Here’s a list of components and features you can find on the outside of a typical PC system unit:

Front Panel:

  • Power Button: Allows you to turn the computer on and off.
  • Reset Button (optional): Allows you to reset the computer in case of a system freeze.
  • LED Indicators: Lights that indicate the computer’s status, such as power, hard drive activity, and network connectivity.
  • Audio Jacks: 3.5mm audio jacks for headphones and microphones.
  • USB Ports: Ports for connecting USB devices like keyboards, mice, flash drives, and external hard drives.
  • Optical Drive (if present): The slot or tray for inserting CDs, DVDs, or Blu-ray discs.
System Unit front Panel
Front Panel
Back Panel
Back Panel

Rear Panel:

  • I/O Ports: A variety of ports for connecting external devices and peripherals, including USB ports, audio jacks, Ethernet (LAN) ports, video outputs (e.g., HDMI, DisplayPort, VGA), and other specialized connectors.
  • Expansion Card Slots: PCIe slots for adding expansion cards like graphics cards, sound cards, and network cards.
  • Power Input: Where the power cable is plugged into the power supply unit.

Side Panels:

  • Access Panels: Removable side panels that provide access to the interior of the computer case for maintenance, upgrades, or component installation.
  • Ventilation Grilles: Perforated areas or fans on the side panels that allow for airflow and cooling.

Top and Bottom Panels (if applicable):

  • Ventilation and Cooling: Some cases may have additional ventilation or cooling options on the top or bottom panels to help with heat dissipation.

Case Design and Aesthetics:

  • Exterior Material: The material used for the case, which can include steel, aluminum, tempered glass, or plastic.
  • Case Design: The overall look and design of the case, including factors like size, shape, color, and any aesthetic features or branding.

Carry Handles (if present):

  • Some PC cases, especially small form factor or portable cases, may include built-in handles for easy transportation.

Locks and Security (optional):

  • Some cases may have locks or security features to prevent unauthorized access to the internal components.

Dust Filters (if present):

  • Some cases have removable dust filters on intake or exhaust areas to help keep the interior clean.

Cable Management Features:

  • Routing channels, grommets, or tie-down points on the backside of the case for neat cable management.

Case Feet or Stands:

  • Raised feet or stands that elevate the case slightly, allowing for improved airflow and stability.

These external components and features play a crucial role in the user’s interaction with the computer and the overall aesthetics of the system. The arrangement and availability of these features can vary depending on the specific PC case and its design.

Desktop PC
Desktop PC

Input Devices

Input devices are peripherals that allow users to interact with and input data into a computer. Here is a list of common PC input devices:

  1. Keyboard: A device with a set of keys, typically arranged in a QWERTY layout, used for typing text and entering commands. Keyboards can be wired or wireless and may include additional features like multimedia controls and backlighting.
  2. Mouse: A pointing device that allows users to move a cursor on the screen and interact with graphical user interfaces. Mice come in various types, including optical, laser, and trackball, and can have different numbers of buttons and features like scroll wheels.
  3. Touchpad: Commonly found on laptops, a touchpad allows users to control the cursor by moving their fingers across a sensitive surface. It often supports multi-touch gestures for various functions.
  4. Touchscreen: Displays that allow direct input by touching the screen with fingers or a stylus. Touchscreens are prevalent on tablets, smartphones, and some all-in-one PCs.
  5. Graphics Tablet (Digitizer Tablet): A device used by digital artists and designers for precise drawing and graphic design work. It consists of a stylus and a pressure-sensitive tablet surface.
  6. Gamepad or Joystick: Input devices primarily used for gaming. Gamepads feature buttons and thumbsticks for controlling games on PCs and gaming consoles. Joysticks are often used for flight simulations and certain types of games.
  7. Trackball: Similar to a mouse but with a stationary ball on top that users rotate to move the cursor. Trackballs are less common but preferred by some users for their precision.
  8. Scanner: A device used to convert physical documents, photos, or images into digital format. Scanners are often used in office settings for document digitization.
  9. Webcam: A camera used for capturing video and images, primarily for video conferencing, live streaming, and online communication.
  10. Microphone: A device for capturing audio input, commonly used for voice chat, recording, and video conferencing.
  11. Biometric Input Devices: These devices, such as fingerprint scanners or facial recognition cameras, are used for security and authentication purposes to unlock computers or access certain applications.
  12. Barcode Scanner: Commonly used in retail and inventory management, these devices scan barcodes to input product information into a computer system.
  13. Light Pen: An obsolete input device that was used with early graphics-based systems to directly interact with the screen by touching it with a light-sensitive pen.
  14. Gesture Recognition Devices: These include cameras and sensors that can detect hand and body movements, allowing for gesture-based control of applications and devices.
  15. Remote Control: Used for navigating media centers, home theaters, and certain PC applications. They come with buttons or touchpads for control.
  16. Numeric Keypad: A separate keyboard with only numeric keys, often used for data entry and calculations.
  17. Game Controllers (Specialized): Devices like steering wheels, flight yokes, and dance mats are used for specific gaming genres.
  18. IR Remote Control: Infrared remote controls are used for controlling applications, media players, and appliances that support infrared communication.
  19. MIDI Controller: Used by musicians and music producers to input musical notes and control music software and synthesizers.

The choice of input devices depends on the user’s needs, preferences, and the specific tasks they intend to perform on their PC. Modern PCs and operating systems often support a wide range of input devices to accommodate various user interactions.


Storage devices

PC storage devices are essential for storing and accessing data on a computer. Here is a list of common PC storage devices:

  1. Hard Disk Drive (HDD): A traditional mechanical storage device that uses spinning platters and read/write heads to store data. HDDs are available in various capacities and are suitable for mass storage.
  2. Solid-State Drive (SSD): A storage device that uses NAND flash memory to store data. SSDs offer faster data access speeds, are more durable, and have no moving parts compared to HDDs.
  3. NVMe SSD: A high-speed SSD that connects directly to the motherboard via the NVMe (Non-Volatile Memory Express) interface, providing even faster data transfer rates than SATA SSDs.
  4. External Hard Drive: A portable HDD or SSD housed in an external enclosure, used for data backup, storage expansion, and data transfer between computers.
  5. USB Flash Drive (Thumb Drive): Small, portable storage devices with USB connectors for transferring and carrying files.
  6. Memory Card: Compact, removable storage cards used in digital cameras, smartphones, and other devices. Memory card types include SD, microSD, CF, and more.
  7. CD/DVD/Blu-ray Drive: Optical drives for reading and writing CDs, DVDs, and Blu-ray discs. These drives are becoming less common due to digital distribution.
  8. Network Attached Storage (NAS): A dedicated device or server connected to a network for centralized data storage and file sharing, often with multiple HDDs or SSDs.
  9. RAID Array: A setup that combines multiple hard drives or SSDs to increase storage capacity, data redundancy, or performance.
  10. Cloud Storage: Online storage services (e.g., Google Drive, Dropbox) that allow users to store and access files remotely via the internet.
  11. External SSD: A portable SSD in an external enclosure, offering fast data transfer speeds and durability for on-the-go data storage.
  12. External Optical Drive: A portable CD/DVD/Blu-ray drive that connects to a computer via USB for reading and writing optical discs.
  13. External Hybrid Drive: A combination of an HDD and a small SSD in a single enclosure, offering a balance of storage capacity and speed.
  14. Tape Drive (Less Common): Magnetic tape storage devices used for long-term data archiving and backup in enterprise environments.
  15. Floppy Disk Drive (Obsolete): An outdated storage device that used 3.5-inch or 5.25-inch floppy disks for storing data. These are no longer in common use.
  16. Zip Drive (Obsolete): An older removable storage device that used Zip disks for data storage. Zip drives are no longer widely used.

The choice of PC storage device depends on factors like speed, capacity, portability, and intended use. Many users use a combination of these devices to meet their specific storage needs, balancing factors like cost, performance, and convenience.

Output Devices

Output devices are peripherals that display or provide information to users based on the data processed by a computer. Here is a list of common PC output devices:

  1. Monitor (Display): A visual output device that displays text, images, videos, and graphical user interfaces on a screen. Types of monitors include:
    • LCD (Liquid Crystal Display) Monitor
    • LED (Light Emitting Diode) Monitor
    • OLED (Organic Light Emitting Diode) Monitor
    • Curved Monitor
    • Gaming Monitor (with high refresh rates and low response times)
  2. Printer: A device that produces physical copies of digital documents or images. Types of printers include:
    • Inkjet Printer
    • Laser Printer
    • Dot Matrix Printer
    • 3D Printer (for creating physical 3D objects)
  3. Speaker System: Output devices for audio, including speakers, headphones, and earphones, which provide sound output for music, games, videos, and other audio content.
  4. Projector: A device that projects a computer’s screen onto a larger surface, such as a wall or screen, for presentations, movie viewing, or large-scale displays.
  5. Headset with Microphone: Audio output and input device combined, used for gaming, communication, voice chat, and multimedia applications.

The choice of output devices depends on the type of information or media being presented and the intended audience or user. Modern PCs can connect to a wide range of output devices to meet various needs, from multimedia enjoyment to professional presentations.


Portable External Devices

Portable external devices for PCs are peripherals and accessories that can be easily connected to a computer and used on the go. These devices enhance the functionality, versatility, and portability of a computer. Here is a list of common portable external devices for PCs:

  1. External Hard Drive or SSD: Portable storage devices that provide additional storage capacity for backups, file transfers, and data storage. They connect via USB or Thunderbolt ports.
  2. USB Flash Drive: Small, portable storage devices with varying capacities for carrying files, documents, and data between computers.
  3. External Optical Drive: Portable DVD or Blu-ray drives for reading and writing optical discs, useful for laptops without built-in drives.
  4. Portable Docking Stations: Devices that expand a laptop’s connectivity options, providing additional USB ports, video outputs (e.g., HDMI, DisplayPort), and Ethernet connections.
  5. External Graphics Card (eGPU): An external GPU enclosure that allows laptops to connect to a dedicated graphics card for enhanced gaming and graphics performance.
  6. Portable Wireless Router: A compact router that creates a Wi-Fi hotspot for multiple devices, often used while traveling or in locations with limited connectivity.
  7. Portable Printers: Small, battery-powered printers that can be used to print documents and photos while on the go.
  8. Portable Scanners: Compact scanners that allow users to scan documents and images remotely, often used in business and fieldwork.
  9. External Battery Packs (Power Banks): Portable chargers that provide additional power to laptops, smartphones, tablets, and other USB-powered devices when no electrical outlet is available.
  10. USB Hubs: Devices that expand the number of available USB ports on a computer, making it easier to connect multiple peripherals.
  11. External Keyboards and Mice: Compact, wireless keyboards and mice that can be connected to laptops or tablets for more comfortable and efficient typing and navigation.
  12. External Display Monitors: Portable, lightweight monitors that connect to laptops or other devices to expand screen real estate for productivity or entertainment.
  13. Portable Speakers: Small, battery-powered speakers for better audio quality during presentations, meetings, or personal entertainment.
  14. Digital Drawing Tablets: Compact drawing tablets with styluses for artists and designers to create digital artwork on the go.
  15. Portable Document Cameras (Visual Presenters): Devices used for displaying documents, books, or objects during presentations or teaching sessions.
  16. Portable Webcams: External webcams with high-quality video and audio capabilities, often used for video conferencing and live streaming.
  17. Portable External SSDs with Built-in Card Readers: These devices combine storage with card readers, making them useful for photographers and videographers who need to transfer data from memory cards.
  18. Portable Barcode Scanners: Handheld devices for scanning barcodes and QR codes in inventory management, retail, and logistics.
  19. Portable Barcode Printers: Mobile printers for generating barcode labels and tags on the go.
  20. GPS Receivers: External GPS devices that provide location data for mapping, navigation, and geolocation applications.

These portable external devices enhance the functionality and convenience of laptops and other portable computers, allowing users to extend their capabilities and adapt to various work, travel, and entertainment scenarios.

Portable HDD
Pen Drive
Portable Scanner
Portable Printer

Types of Personal Computer

A personal computer (PC) is a versatile computing device designed for individual use, offering the ability to perform a wide range of tasks, such as word processing, internet browsing, gaming, and multimedia entertainment. PCs consist of hardware components like a central processing unit (CPU), memory (RAM), storage, and input/output devices, all controlled by an operating system (e.g., Windows, macOS, Linux). They are characterized by their adaptability, allowing users to install software, upgrade components, and tailor the system to their specific needs.

Types of Personal Computers:

  1. Desktop PC: A stationary computer typically consisting of a tower or all-in-one design. Desktops offer high performance, customization options, and are suitable for various tasks, including gaming, content creation, and office work.
  2. Laptop (Notebook) PC: Portable computers with a built-in screen, keyboard, and trackpad or pointing device. Laptops are suitable for on-the-go computing and come in various sizes and configurations, from ultraportable notebooks to powerful gaming laptops.
  3. Tablet PC: Compact, touchscreen devices often used for web browsing, media consumption, and lightweight productivity tasks. Some tablets offer detachable or attachable keyboards for added versatility.
  4. Ultrabook: A lightweight and slim laptop designed for portability and long battery life. Ultrabooks typically offer a balance of performance and portability.
  5. Netbook (Obsolete): Small, low-powered laptops primarily used for basic web browsing and email. Netbooks have largely been replaced by more capable devices.
  6. Chromebook: Laptops running Google’s Chrome OS, designed for web-based computing and productivity. They offer affordability, fast boot times, and integration with Google services.
  7. Workstation: High-performance PCs optimized for tasks like 3D rendering, scientific simulations, and professional content creation. Workstations often feature powerful CPUs, GPUs, and extensive memory.
  8. All-in-One (AIO) PC: Desktop computers with a compact design, integrating the monitor and computer components into a single unit. AIOs are space-saving and suitable for general computing tasks.
  9. Gaming PC: PCs optimized for gaming, often featuring powerful CPUs and dedicated graphics cards. Gaming PCs can be custom-built or purchased as pre-configured systems.
  10. Mini PC: Compact desktop computers with a smaller form factor, suitable for home theater PCs (HTPCs), digital signage, and embedded applications.
  11. Server: PCs optimized for hosting and managing network services, applications, and data storage. Servers are typically used in enterprise environments but can also be used in home networks.
  12. Raspberry Pi (Single-Board Computer): A credit card-sized computer designed for educational and hobbyist purposes. Raspberry Pi boards are used for programming, electronics projects, and small-scale computing tasks.
  13. Stick PC: A Stick PC is a compact, portable computer that resembles a USB flash drive. It typically runs on Windows or Linux and is suitable for basic computing tasks and media playback.

These types of personal computers cater to various user needs, from general productivity and entertainment to specialized tasks like gaming, content creation, and server hosting. Users can choose the type of PC that best suits their requirements and preferences.

Personal Computer

Photo credits: All images used in this article are courtesy of their respective vendors and websites. We acknowledge and appreciate their contributions to the world of personal computer components.


In conclusion, personal computer components are the building blocks of modern computing, each contributing to the overall functionality and performance of your PC. From the CPU’s processing power to the GPU’s graphics capabilities, understanding these components empowers users to make informed choices and optimize their computing experience. As technology continues to evolve, staying knowledgeable about these elements ensures that your computer remains a valuable tool in an ever-advancing digital landscape. Embrace the world of personal computer components, and unlock the full potential of your machine.

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Computer Hardware: https://spca.education/category/computer-hardware/

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