Parts of a Computer - Hardware

Computer Anatomy - Physical Components

In the last lesson, we covered the definition of a computer, as well as the four parts needed for the machine to function - hardware, software, data, and the user. Now, we'll determine the most common forms of hardware.

Once more, Hardware is the physical pieces of your computer. There are many pieces that can be connected, but let's go over the basics.

The Monitor is your viewing window into the computer. They come in many shapes and sizes, brands, and sometimes can even be noncomputer hardware.

Monitors usually come in 3 forms:

• CRT – Cathode Ray Tube monitors are some of the oldest to exist, and can be seen in older computers and TVs. If you're old enough to remember VCR technology, most TVs of the time were CRT. They have a limited level of quality, give off a lot of warmth, and are hard to store and move due to size and weight.

• LCD – Liquid Crystal Display monitors are much more modern. These can be seen in a lot of computer and phone screens in the modern day, especially if it's a few years old. Unlike the CRT, they contain pixels as well as subpixels for the display that are lit with a fluorescent light behind the screen, meaning the resolution can be pushed much farther than their predecessor. However, the screen quality is effected by your viewing angle - if you're not right in front of the screen, but rather to the left, right, or even above, you may notice it's hard to see the screen and colors look incorrect. When you look at the display from a large angle, the light has no direct path from the back light to your eye, making the image darker the more obtuse the angle is. Plasma monitors were created in an attempt to replace these screens, but plasma has a terrible issue with burning an image into the screen, ruining the quality after awhile.

• LED – Light Emitting Diodes are some of the newest developments in screen technology. Instead of a fluorescent backlight, they're replaced with light-emitting diodes. Because of this, they're smaller and lighter than LCD screens, making them great for TVs, computers, and phones that are slimmer. Newer displays have the polarizing filters closer together meaning that you can see it from a wider angle than older LCD displays.

There are even more screen types, like OLED (Organic Light-Emitting Diode) and DLP (Digital Light Processing), but these are usually what you'd see in your day to day. You can even connect TVs and other screens as a monitor. These displays connect through an HDMI cable (High Definition Multimedia Interface) - usually these will be HDMI to HDMI, meaning the plug will be identical on either side, and can be inserted in the back of the monitor to connect to the back of your computer. However, not all monitors take HDMI to HDMI - older hardware may need a specific cord, so always do your research and check for a manual, which you can usually find online.

When talking about monitors, there are also type differences based around Resolution. Monitor resolution describes the visual dimensions of any given display. Measured in width and height, monitor resolution is comprised of a specific number of pixels. Pixels, or picture elements, are the smallest physical points on a display, as well as the base components. Pixels are therefore the building blocks of any image you see on your screen. The higher a monitor’s resolution is, the more detailed an image can be because a higher resolution monitor will be made up of more pixels than a lower resolution monitor. You may see numbers like 1920x1860 - these are the width x height of the pixels within the monitor. However, the same sized screen could have a different resolution in a different brand. This is based on the Pixels Per Inch (PPI) which is how densely the pixels are packed. If you have two 25-inch screens, but one has 88 PPI and the other has 69 PPI, the 88 PPI screen is going to show a higher definition image because it has more pixel information to give per inch.

Some monitors are called All In One Monitors - these will have all the components to run without a PC Tower (meaning its own CPU, RAM, and other processing components). These usually come with their own pros and cons, and we'll discuss that in the next lesson.

(Pictured: HDMI Cable)

The most important part of your computer is the PC tower, or personal computer. It goes by many names: tower, main unit, chassis, computer case, and more. This houses all the hardware for digital processing - your CPU, motherboard, RAM and ROM, graphics cards, etc. - and is the central hub for most of your peripherals. They come in, again, many shapes and sizes and may differ in processing speeds and storage.

Most, if not all, machines come with an Operating System pre-installed - meaning when considering buying a new unit, you'll have to consider the differences between them. For now, let's move on to your peripherals.

(Pictured: 3 Dell PC Towers of varying size)

With a computer, you'll need a way to give the machine your inputs. Peripherals are usually the way to achieve this, and they could either be built into the machine or added separately. Most are connected via a USB cable (Universal Serial Bus, which is an industry standard cable for most peripherals), but some can be connected through a wireless method like a dongle (a wireless transmitter that connects to a USB port) or Bluetooth (a short-range radio signal from your machine to the peripheral).

The main two peripherals will be the Keyboard and the Mouse.

The keyboard is the best way to type and input words, letters, symbols, and commands into your machine. The computer's OS will usually have Shortcuts, or keyboard combinations, that allow simple actions to be preformed. It'll be hard to memorize all of these but there are stickers and cheat sheets out there to make life easier, and some of the shortcuts will be used commonly enough that they'll become second nature after awhile. Within your systems settings, accessibility features can be activated so you can use a digital keyboard for typing with the mouse.

Keyboards are mostly the same across brands and styles, though there are mini-keyboards like number pads for smaller laptops that may lack one as well as half or one-handed keyboards meant for gaming. There are a lot of cosmetic and "feel" differences, such as internal LEDs, mechanical keyboards vs their much quieter siblings, custom keycaps, and more.

(Pictured: Windows 10 Shortcuts List)

(Pictured: Mac OS Shortcuts List)

The Mouse is your connection to the cursor, a movable indicator on a computer screen identifying the point that will be affected by input from the user. With your mouse, there can be as few as 3 but as many as 20 buttons - we'll only worry about a few though.

(Pictured: 14 different mouse variations)

There are many different ways to give a mouse input. The image above may seem overwhelming at first, but let's break them down into sections.

Here are the main types of mouse:

Typical Variations

• Ball/Mechanical
• Wheel/Scroll
• BlueTrack
• Touchpad
• Trackball
• Gaming

Unique Variations

• Vertical - Ergo mouse that eliminates arm twisting that a normal mouse causes.
• Stylus - Pen-style mouse that is used in conjunction with tablets and screens for designers.
• Trackpoint- Dot mouse in the keyboard for quick adjustments without moving your hands.
• Foot- "Shoe" style mouse where one foot controls movement and the other, button-presses.
• Presentation - Handheld remote mouse for presentations and powerpoints.
• 3D - Mouse designed to navigate 3D space for designers, architects, and 3D modelers.
• Roller Bar - Bar-style mouse below the keyboard, like a touchpad but with larger surface area.
• Finger - highly unique single-finger mouse that you wear like a ring or hold like a small remote.

When it comes to this device, the first list is what's seen most often in modern office buildings, home computers, cafes, and libraries. The second are accessibility options or peripherals best used with specific computer types. To save time, space, and mental energy, we'll go over the bare basics of the typical variations and I'll link deeper research if you choose to read more.

Ball/Mechanical Mouse

One of the earliest mouse to be used with a computer. Tracks motion with a rubber ball that spun in the direction you moved the mouse, which the sensor takes and utilizes to decide which way to move the pointer. These are rare for the modern user, but your grandma may still have one.

Wheel/Scroll Mouse

By far the most widely used mouse. This type typically uses a laser embedded in the bottom to track movement, but can use a ball like the style above. When a laser is used, it's also known as Laser Mouse and Optical Mouse.

BlueTrack Mouse

Microsoft's tracking technology was the first leap towards improving Laser Mouse technology. With a laser mouse, the laser must track against a smooth, dark surface for optimal use, but thanks to BlueTrack, you can use your mouse on just about any surface from carpet to granite. While the tracking is touted as superior, the internal sensor tends to give out in under a year of use.

Touchpad Mouse

With some computers, the mouse and keyboard will be built into the system (the most notable version being a laptop). A mouse built into a computer uses pressure/touch to move and activate the mouse. These will typically have two buttons aligned with the bottom for left and right click, and sometimes has functionality to scroll when touched with two fingers at once. Though most touchpads feature two buttons, some are pressure-sensitive and may be tapped to function as buttons.

Trackball Mouse

A trackball mouse resembles an inverted mechanical mouse. The ball is located at the top of the mouse and is used to spin the cursor and steer it. Its design is more ergonomic since it eliminates the need for the user to move the mouse manually, resulting in less wrist and hand movement.

Gaming Mouse

Multiple buttons are frequently seen on these, which may be customized to activate keyboard keys or shortcuts for gaming purposes. The ergonomic design aids the player, and they are also reputed to be more accurate than the ordinary mouse. Some say this type is more durable, but with rising prices and lower quality, I hesitate to endorse that claim.

When it comes to a mouse and keyboard, there are many options: styles, colors, connection types, accessibility, all of this comes into play when deciding what to use.

Now when it comes to the other peripherals, there are too many to go over, but I will list the other categories available, though this is NOT a complete list.

Tablets, joysticks, scanners, monitors, speakers, printers, external hard drives, webcams, projectors, and media card readers are all things that can connect to your machine - but be warned, you have a limited about of USB slots. Most computers come with at least two, some will come with more, but if you ever find yourself running out, consider purchasing a USB Hub, which will extend 1 port to multiple. I own my own USB Hub, but it has a separate power supply because it has 7 ports coming from one. When you use too much power in one USB slot, the peripherals may have trouble getting enough energy to function (ie. your mouse and keyboard may react slowly when too many things are plugged in).

I'll give more information and suggestions on these peripherals in a later lesson.

Now that we covered peripherals, we can cover what you don't see as often - the inside of your machine.

(Pictured: An opened computer tower with many labeled parts)

If you decide to open the computer case and take a look, make sure to unplug the computer first.

Before touching the inside of the computer, you should touch a grounded metal object—or a metal part of the computer casing—to discharge any static buildup. Static electricity can be transmitted through the computer circuits, which can seriously damage your machine.

The small components that help your computer run is also considered hardware. While it may seem extremely complicated, once you know your way around, things start to be way less daunting than before.

As mentioned in the last section, the CPU (central processing unit) is used for processing data submitted by the user by following instructions known as programs to give an output. It's vitally important to the function of your machine. You may see machines that say Intel Core Processor i9 or the Apple M2 Ultra - these are types of processors, and they have internal specifications that dictate how well they run. 

We'll go over the specifications of the CPU as well as the rest of the internal machine in the "how to research and buy a computer" section of this course.

The CPU is connected onto the Motherboard. A motherboard is the main printed circuit board in most computers. It holds and allows communication between many of the crucial electronic components of a system and provides connectors for other peripherals. The graphics, network, and sound cards all slot into the motherboard, as well as your RAM and ROM. Consider the motherboard as the body of your computer, while the CPU is the brain. RAM is your short term memory for most processes, ROM is the long term, low-level storage memory for root computer processes.

RAM tends to be data that you aren't actively saving to your computer - unsaved word documents, video games in progress, and web browsers are all examples of this. RAM stands for Random Access Memory - RAM is volatile, meaning data is retained in RAM as long as the computer is on, but it is lost when the computer is turned off. When the computer is rebooted, the OS and other files are reloaded into RAM, usually from a more permanent means of memory.

ROM is the base-level storage of your machine. This tends to be start-up procedures and preparing the OS for use. It's also hard to change or adjust digitally, as there isn't much access to it to prevent larger system errors from someone messing with things they shouldn't.

More permanent types of memory are HDD (Hard Disk Drive) and SSD (Solid State Drive). The HDD, also known as the hard drive, is where software, documents, and other files are stored. When you turn the computer off, the information is safely stored onto the hard drive. When you run a program or open a file, the computer copies some of the data from the hard drive onto the RAM. When you save a file, the data is copied back to the hard drive. The faster the hard drive, the faster your computer can start up and load programs. The hard drive writes to a disk and uses mechanical pieces to store information. HDDs are cheaper and are easier to recover data from if damaged than their SSD cousins. SSDs on the other hand, while more expensive, are faster, quieter, smaller, more durable, and consume less energy. Back in the day, SSD was also limited on size compared to the HDD but nowadays, you can find them in just about any size you need. HOWEVER, if your SSD becomes corrupt, it is MUCH harder to retrieve lost data. If you're working with large, important files, HDD is an easier route.

The power supply is what sends electricity through your system. Think of it like the blood of your machine - no power, no life. Standard computer towers require a power cord to be plugged into a wall outlet or extension cord for continuous power, while laptops, tablets and phones have a power supply that slowly releases stored energy over time.

Most computers have a heat-sink - processing takes a lot of power and energy, which increases the temperature of your machine the more you use it - and this heat sink is usually a grid of metal pins attached to a fan to cool the pins as fast as possible. When your fan gets dusty or old, it may fail, which can bring your computer to dangerous temperatures that can damage your hardware. It's a good idea to open up your computer tower's case and clean it out with canned air from time to time. Knocking off dust and debris from your internal components can help them to function better. The heat sink can also be used in conjunction with additional air and liquid coolers, which are excellent for machines doing intense work like running physics engines in 3D modeling programs or enduring high-graphics gameplay.

Expansion cards like the graphics, network, and sound cards all hold different roles and act as extensions of the motherboard. A graphics card houses your GPU (Graphics Processing Unit) and is responsible for what you see on your monitor. Most computers have a GPU built straight into the motherboard but you can add a faster video card to one of the expansion slots to get better performance. A sound card is responsible for what you hear in the speakers or headphones. Most motherboards have integrated sound, but you can upgrade to a dedicated sound card for higher-quality sound. The network card allows your computer to communicate over a network and access the Internet. It can either connect with an Ethernet cable or through a wireless connection (often called Wi-Fi). Many motherboards have built-in network connections and a network card can also be added to an expansion slot. You may have another card built into your machine for Bluetooth, but this can also be achieved with a dongle, or USB adapter.

The CD drive, while an optional piece of equipment in the modern world, is used for reading, writing, and downloading content from CDs, DVDs, and sometimes Blu-ray discs. I personally believe we should all have CD trays still, but it doesn't work nicely with thin laptops and all in one machines that are known for being lightweight. In older machines, you may just have a CD-ROM, which is only used for reading and downloading from discs, but not writing new information to them. Even older machines may have a Floppy Disc drive, which reads and writes information onto a small piece of storage. The biggest floppy disc is 1.2 MBs - a single 3-minute MP3 is usually about 3 megabytes; a 2-page Word document (just text) is about 20 KB, so 1 MB would hold about 50 of them.

The modem and router pictured in the image above will be topics we go over in the "What is the Internet?" lesson.

These are all the main components of your machine from inside and out. Next, we'll go over the software inside all of these pieces, as well as the most common types of software you may find on a work, school, or otherwise corporate machine.