Installing Hardware and Display Components
This is a guide on installing hardware and display components.
Hard Drive Types
In this presentation, we'll introduce the hard disk drive or what's more commonly known as the hard drive. And you can think of the hard drive as the file cabinet of your system. It's where you store data permanently.
[Video description begins] Hard Disk Drive Systems. [Video description ends]
So all of your documents, your music, your pictures, your videos. Anything will go on the hard drive and that's where it can be located when you need it. And it usually offers fairly fast access so that, in most cases, I can go through my operating system and just double-click on a file, and it opens.
[Video description begins] Hard disk drive is abbreviated as HDD. [Video description ends]
But in terms of the internal components, the structure, there are three main components, the controller, the hard disk, and a host bus adapter or HBA. Now, I'll actually start in the middle of that list and talk about the hard disk itself. And it is aptly named because it's a solid metal disk. And it's made of a substance that will conduct electricity very well. Because the information is written by an electric charge that is applied to the disk which creates a very small magnetic field. You'll often hear the term magnetic storage used.
And that each disk is in and of itself referred to as a platter. But for every platter there is a top surface and a bottom surface, and in most cases there's multiple platters as well. So if for example you had three platters, well then you have six writable surfaces, two for each platter. And this of course helps to increase the capacity of the drive itself. Now the controller, as its name indicates, controls all of the operations of the drive. All of the moving parts because the platters spin. And then there's a read/write arm and a head, we'll talk about that in a moment, that is responsible for actually reading or writing the data.
So they all move, and all of that is controlled by the controller, and it also handles how the data itself is encoded onto the platters. Now, the most common type of interface for hard drives these days is what's known as serial ATA or SATA. We'll talk about that later on. But that's how it interfaces with the computer itself. So the controller essentially talks to the rest of the computer over that interface. Now the host bus adapter or HBA is a translator. Converting signals from the computer into the electrical signals that can be written on to the disk and then vice versa. It converts the electrical signals into data that the computer can understand.
Because at the level of the hard drive, as I mentioned, we're just talking about electric charges applied to the disk to create a magnetic field. Well, that's not what the computer understands. The computer needs binary digits, or bits, a one, or a zero. So this might be a little simplistic at this point but you can think of the presence of an electric charge equating to a one. And the absence of an electric charge equating to a zero. So the host bus adapter is responsible for performing that translation. If it receives a bunch of ones and zeros from the computer, it has to translate them into the electrical charges.
When it reads the data, it has to convert those electrical charges back into ones and zeroes, so it literally does the translation. Now these days, all of those are usually built into the disk itself. In older systems, the controller and the host bus adapter may have actually been separate, but that's going back quite a ways. Now looking more closely at the anatomy of a hard drive, number one is the platter. And again, each platter has two surfaces, a top and a bottom. And then there are usually multiple platters to increase the capacity. Number two is the spindle, that is the axis around which the platters spin. Number three is the head, and that is the actual read/write point. So that's where the electrical charges are applied and/or read. The arm moves the head back and forth, so it can access any position on the platter.
The actuator axis, number five, is the point about which the arm rotates. And six through eight are the physical connections, the power and the data cable to connect it to the rest of the system. And nine is the actuator which is the motor that moves the arm back and forth. So as mentioned, magnetic hard disks are named this because it uses magnetic fields to store the data. And these days, this is still the most commonly used type of storage. This is the primary storage of most desktop computers. And they do offer several benefits. It's a very mature technology. It's been around for a long time, and the technology has just been improving and improving. So they are very reliable.
Data on a hard disk will stay there, more or less for the life of the disk itself, but nothing's 100%. They still are moving parts, so they can fail. You've probably heard of people saying my hard drive crashed. So you always still want to back up your data. But they are very reliable, and they're relatively inexpensive. Again, because they have been around so long, the technology has only been improving. But because they're so common, the price has been coming down. Now there are different sizes and this refers to the width, which essentially is the minimum size necessary to accommodate the disk inside.
[Video description begins] 1.8in vs. 2.5in vs. 3.5in. [Video description ends]
So 1.8 inch, not very commonly used but it does exist. The most common are 2.5 in a laptop or perhaps a portable external drive. And 3.5 inch is the mainstream type used in a desktop system. Now, a solid-state drive is a little bit different.
[Video description begins] Solid State Drive is abbreviated as SSD. [Video description ends]
There is essentially no moving parts. It uses what's known as nonvolatile NAND flash memory for storage. Now, that's a bit of a mouthful, but nonvolatile for starters means that it does not require power to retain its data. Early types of memory were known as volatile, and if the power went out, the data in them was lost. So for permanent storage, that can't happen, so it's nonvolatile memory. NAND actually refers to NOT-AND, and it's just a logical processing mechanism that says, based on this input, this is the output you'll get.
And flash memory means of course that it can just be stored as memory, but it can be rewritten very easily. So any type of information can be written over and or erased, if you will, that's flash memory. But in terms of benefits, we have much faster access time, because it's not a spinning disk, it's just a collection of chips. So each piece of data that is written has an address, and it just has to go to that address to retrieve that data, so it's much faster. They are very reliable because there's no moving parts. They require less power, they produce less noise, and they're usually physically smaller as well. Now, that said, they tend to be a little more expensive and they do run a little bit hot.
So you do need to ensure that you have adequate cooling in your system as well. And then finally, they do have hybrid drives which are a combination of hard drives with some solid-state memory as well. So you get usually increased capacity because hard drives typically tend to store a little bit more than solid-state. But you get some of the performance benefits of solid-state. So it's still the traditional platters, but along with the high speed flash memory.
These will cost a little bit more than a traditional hard drive, but not as much as a full solid-state drive. They tend to have greater capacity than the solid-state drives. And they do offer performance that is probably somewhere in between, as its name indicates, it is a hybrid. So those are the basics of hard drives. And of course, we will talk about more characteristics as we move through the course. But ultimately, it represents your permanent storage and then how that data is simply accessed when needed.
Memory
In this presentation, we'll introduce random access memory, or RAM. And this is often referred to as simply system memory or even just memory. But if we go back to the analogy of a hard drive being thought of as a file cabinet, then you can think of RAM as your desk. So if I'm working at my desk and I need a file, I will get up, walk to the file cabinet. Get the file that I need and bring it back to my desk, and I'll work on it there. So it's what you're doing right now. Now, it doesn't have to be just one file, maybe I can grab three or four. As long as I feel like I've got enough space on my desk and I can manage it all, there can be multiple files in memory at any given time.
But there wouldn't really be any scenario where I would need every file at my desk. My desk just wouldn't be big enough nor would I be able to manage it all. So normally, there's far more storage than memory, okay? But it is whatever you need to work on right now. It's still physical hardware, it's still a form of storage, but it's temporary storage. So it holds the files that I'm working with at this point while I'm making changes. Then once I'm finished, I go and I put it back in the file cabinet. So that way there's more space on my disk freed up as I finish working with each file, I put it back in the file cabinet. So now I've got room to do other things, okay?
Now, it's certainly very fast-access because again there's no moving parts. They're just chips, so in fact, it's very much faster than traditional magnetic storage. But it is volatile, so that's why it's temporary storage. Volatile means it needs power to retain any information. So if the system completely failed or the power went out, whatever was in memory is lost. So any changes that you have made to a file that have not been saved or put back in the file cabinet, if you will, do get lost. Now, these days there's lots of built in mechanisms in our software applications to automatically save files so that we don't lose all that work.
But that's because of the software, the nature of the memory itself is still to dump its data when the power is lost. So you might think, well, why is it volatile? Why not make it non-volatile? Well, you can, but to this day, non-volatile memory is still more expensive than volatile.
[Video description begins] Laptop Memory. [Video description ends]
Now, if we're talking about a laptop, it's still the same type of physical chip, but laptops, of course, are very much smaller than desktop systems. So the type of physical chip in a laptop is referred to as a small outline DIMM. And DIMM stands for dual in-line memory module. So a regular DIMM would be what you'd find in a desktop. The small outline quite literally is just a physically smaller chip known as a SODIMM. So it’s just clearly smaller to handle the limited space within a laptop. And they are usually 2.5 to 3 inches in size with a varying number of pins.
That's the point of contact to the socket it sits in in the laptop itself. So there can be 72, 100, 144, or 200 pins. Now, in terms of considerations for laptop memory, you may at some point feel like you want to upgrade. You can get more memory or perhaps faster memory. Ad before you do this, you generally should consult the motherboard user guide and confirm that it in fact can be upgraded. Most laptops will allow you to do this. They have a little door on the bottom that can be opened, and you can access the memory. But some models have sealed bottoms, and the memory is quite literally soldered onto the motherboard, so it's not actually upgradeable. But if you can upgrade, then you might just want to determine how much memory you are currently using before you run out and buy additional memory.
On a Windows system you can pull up Task Manager, or Resource Monitor to find out what the current memory usage looks like. And you usually can intermix modules from different vendors. As long as it's physically the same size and the same basic specifications, it's usually fine to mix them, but it's not bad to keep them all consistent either. So again, if you can replace, turn everything off, disconnect the power, and then flip it over.
[Video description begins] Replacing Laptop Memory. [Video description ends]
On the bottom, again, there's usually a door that can just be removed. And the chip itself usually is just kind of inserted on a bit of an angle or diagonally. And you just kind of sit it in the socket, and you press it down, and there are usually little clips that snap into place. And basically, just make sure that it is seated in there correctly. And then, of course, replace the compartment door to complete the upgrade. So it's usually just a matter of finding out what's in there in the first place and maybe bringing that with you to say, look, can I get this particular chip? So that you'll know it's the correct specifications and the correct size. But if it is a system that allows you to upgrade, it's a fairly simple process.
Input Devices
In this presentation, we'll go over several external or peripheral devices that you will likely encounter in terms of connecting and configuring devices. Beginning with mice and of course, the mouse is one of the most common interface devices. And in terms of physical connections, USB, if it's wired, would certainly be by far the most common these days. You might still encounter a PS/2 with an older desktop or laptop, but that would be quite rare these days. The PS/2 connector was sort of a cylindrical connector about the size of maybe the tip of your little finger. And if it's wireless, then Bluetooth. But the receiver that is connected to the physical computer itself would probably still be a USB connection, but then the mouse just transmits via Bluetooth to the receiver.
And in terms of configuration for most mice, you can just go to the Control Panel applet in Windows, whereby you can update the driver if necessary. Although, that again is not really very common if it's just a basic two button mouse with a wheel. You certainly can configure how the buttons behave and how the wheel behaves, but you wouldn't really need to update the driver. That would pretty much just be for an advanced gaming mouse or something for 3D graphics. Where there's a lot of different specific configurations and/or controls on the device itself. The pointer options usually are just the way you want the pointer to appear.
And again, the button configuration certainly can be set up if you're right-handed versus left-handed, for example, and how many pages it might scroll when you roll the wheel. And then of course its counterpart the keyboard is certainly still the primary method for inputting data into a PC. And it would have the same connections as a mouse USB again, overwhelmingly the most common, maybe a PS/2 for older systems, and Bluetooth. And in many cases, the mouse and the keyboard are sold as a set if it's Bluetooth, and there's a single receiver for both of them. And again, these days many keyboards are also equipped with additional features such as a volume control, a brightness control for the screen.
Programmable buttons that can be used to launch your most common applications. But that certainly depends on the make and the model. Scanners are used to make digital copies of existing paper photos, documents, and drawings. Really anything that's on paper can be scanned and fed into the system. Again, the connections are typically USB but it might offer a wireless connection in some cases, depending on the make or model. And in terms of the form factor, you tend to find them with all-in-one devices. So multi-function printers, scanners, copiers, or just a flatbed individual scanner all by itself. So that's the only thing it does. Again, that depends on what it is you are looking for.
But these days, it's not uncommon at all to have the scanner built in to a printer so that you have everything in one. Then we have optical drives, which can retrieve and/or store data on optical disks. So as opposed to the magnetic disks that we talked about when we were examining hard drives, these are written to and read from using a laser, hence optical. So we have the compact disc or CD, and they come in the varieties of C readable or CD readable and writable. The term used to be generally known as burning the CDs, but it simply means that you can write to it if you have a burner.
Then DVDs came along. And they do have a greater capacity than CDs, so they tend to be a little more favored these days. And again, there was the DVD readable, the DVD readable and writable, and then Blu-ray, named because quite literally the laser that is used is blue. In DVDs and CDs, it was red. And a blue laser actually has a higher frequency than a red laser. Therefore, it's actually capable of greater storage capacity and higher resolution if you're talking about watching videos. It can encode more data with that tighter focus of the laser. And again, with Blue-ray, there is the readable, which would basically be if bought a movie, that is only readable.
You don't overwrite it, but the BD-RE, literally means rewritable, so you can use that to store your own data. Smart card readers, commonly used for personal identification, access control, authentication, or financial transactions. There is quite literally a chip, usually on the card. So most of us these days probably have a bank card or a credit card that contains a chip. So the reader, obviously, reads the information from that chip. And they can be both external, usually USB, or built-in, depending on the device. And finally, touchscreens.
This is a type of monitor equipped with sensing devices. So it obviously knows where you are touching. Commonly used in situations where mice and keyboards just aren't possible, such as an information kiosk. So you just touch the screen instead of typing in anything. And of course, we are all very familiar with this with our phones and tablets. Now, they're also considered to be output devices, even though they accept input from us, because, of course, it displays back to us. So that's an output device as opposed to an input, so they are actually considered to be both.
Wireless Cards
In this presentation, we'll take a look at some options for enabling systems to connect to Wi-Fi, or a wireless network. And, of course, this enables the system to be able to connect to the network without any cables. So you don't need to run a cable to the router directly.
[Video description begins] USB Wi-Fi Adapter. [Video description ends]
Now, clearly, this is much more convenient for systems such as laptops, where you are very mobile. It may not be as necessary if you're talking about a desktop system. They tend not to move. But in a home environment, most places don't have ethernet wired networks in their houses. So it still gives you the convenience of being able to place the physical computer really, just about anywhere, and still connect to the wireless. So you can just get a USB Wi-Fi adapter, and this is little more than the connector itself with an antenna attached. So really, that's all you need. The antenna picks up on the signals, and then the connection just goes into any available USB slot.
And you might be looking at upgrading any particular system with this capability. Because even some older laptops may not be equipped with wireless network adapters. Just about any newer system would be these days, but older ones, not necessarily. And it also gives you the benefit of being able to use it on different devices. So if for example, in a home environment, you had a laptop and a desktop. If you needed to connect the desktop, you quite literally could just pull it out of the laptop and insert it into the desktop. And you could use it for either one. Now, if it's an actual card, then this is something that is, of course, built in to the system. So some older laptops might have used a mini-PCI connection.
[Video description begins] Mini PCI. [Video description ends]
It's square in shape and has 124 pin edge connection. So it looks fairly similar to a memory module and connects in a very similar way, as well. But as a mini-PCI device, it offered speeds of 802.11g and 802.11b. And that's a little bit of an older type of physical device. These days it would probably be a mini-PCI express, which is a 54 pin edge connection with a more rectangular shape. And you can see that it has a greater variety of speeds. So 802.11a, b, g, and n. So they all offer different specifications, so this one is a little more compatible.
Now, you can also have a cellular card. And this quite literally allows you to connect your device, probably a laptop, to the Internet using cellular signal. So as long as you have a provider, then you can more or less connect to the cellular network, and get your Internet that way. So the same way that we can get Internet on our phones, you use this for your device. It’s built in mobile broadband. It can connect to 3G or 4G networks, so again, it's just a chipset that is built-in to the motherboard or on the card itself. Or possibly even in a USB stick, which is very plug-and-play compatible.
You just plug it in. And usually, a Windows system anyway, or a Mac system will probably pick it up automatically and configure it automatically. And then you just connect to the same network that you use for your cell phone or whichever provider you have available to you. But it just enables your laptop or any device to connect over cellular services. So if you are needing to replace a wireless card, again, turn off the laptop, disconnect all power including the battery. Remove the wireless card compartment door. Now that's going to vary depending on the laptop, the make and model. Remove any screws and then remove the adapter from the laptop. Detach the antenna wires.
So there's usually just a little wire that connects it to the antenna, so make sure you detach that. Install the new wireless card. Reattach any wires that you detached originally. And if necessary, install a new driver so that, of course, the operating system can recognize it.
Output Devices
In this presentation, we'll talk about some output devices and we'll go back to the touch screen here. Because again, this really is both input and output. The input obviously, by us touching it, but of course it then just displays what we want to see. So clearly, it is also an output device. And again, they're commonly used in situations where mice and keyboards just aren't really possible, or at least just not convenient. So airports, banks, really any kind of kiosk system is ideal for a touch screen. So again, it's still considered to be an input device, but it returns that which we want to see. So it is therefore an output device as well. A KVM stands for keyboard, video, and mouse.
And again, you would think of all of those as input devices. But what this does is it allows multiple systems to share that input to produce multiple different outputs. So in other words, if you had let's say three different computers, without a KVM you would need three monitors to see everything, three keyboards and three mice. So this allows you to connect a single mouse, a single keyboard and then a single monitor to the device itself, the KVM. And then have all the three of those computers produce or send their output to the KVM so that we don't have to have three monitors, three keyboards and three mice. We just have a single one, and then there's usually a switch or a dial of some kind, whereby you can simply set it to which computer you want to interact with. So in terms of the interface type, you typically would have USB in terms of connecting it to the computer.
But then for the display, it would be probably VGA, or DVI, or digital video input. Or possibly HDMI for newer ones, but again, it's to allow those multiple outputs to go through a single unit. Speakers, of course, to just enhance the computer output in terms of the sound. Laptops do have built-in speakers, but they're usually pretty small and don't have very good quality. So of course, we can enhance that when necessary. The connections are usually what's known as the TRS jack, which stands for tip, ring, and sleeve. Typically, it looks exactly like what you would see on the end of a set of headphones. And the speaker output itself would require some kind of audio adapter.
In some cases, depending on what the speaker type is, a common connection on the speaker end might be a RCA connector. But, again, this is going to be dependent on the speaker itself. Some of them don't have any adapters necessary. The wire goes right into the speaker, so it's not necessary to have an adapter in that case. And when it comes to display devices, of course, this really is just the screen. So, I mean, this is the most common computer output device. Now in a laptop, obviously the screen is built-in, but many laptops can send the output to something else. So again, a VGA, a DVI, or a HDMI would be the output of the laptop so that you can connect it to perhaps a larger screen, such as a digital TV or a projector. And there are many different standards in terms of the sizes and the resolution these days.
So speaking of the projector, this, of course, takes the images generated by the computer and produces them onto a screen or a wall. And again, you can connect any type of system to a projector, but more commonly you would probably see a laptop used because, simply, it's so portable. But you certainly could connect it to a desktop in a more stationary configuration such as a classroom. So the computer that is connected to it just never moves and the projector itself is may be mounted on the ceiling.
But obviously, these are just to do large-scale presentations when you have an audience and you need a much larger screen. And of course printers, there are just a tremendous number of makes and models of printers available. All-in-one typically are printers, faxes, scanners, copiers, thing like that. So multi-function devices. And then, of course, there's color, black and white, depending on whether or not you need any color. And the connections, again, most commonly these days, USB, with respect to a wired connection. But if it's in an office environment, it's more often and now just connected to the network like any other system.
[Video description begins] For example, Ethernet connection. [Video description ends]
It can also network wirelessly. So 802.11, that's WiFi. Bluetooth and infrared certainly can be used as wireless connections, but they typically have limited range and/or require direct line of sight in the case of infrared. So those are certainly less common. But any or all of them can be used to connect any system to the printer or the multi-function device.
System Components
In this presentation, we'll take a look at several different system components beginning with video cards. And, if you're talking about a desktop, then a video card really is just that, a card. It's a very replaceable unit. You could just pop the cover off, take out the old card and put in a new card if you were looking to upgrade. As long as it was the same interface. But, in a laptop, you generally don't see a video card. It's usually built right into the motherboard. So it's not really a replaceable component without replacing the entire motherboard. But most laptops do also have external outputs so that you could send a signal to a secondary monitor, or a projector. So you will still likely encounter at least one of the interfaces listed here.
[Video description begins] Video Cards. Numerous interfaces. [Video description ends]
So VGA is Video Graphics Array, and this has been around for a very long time. But, despite its age, it's still fairly common, it's tried-and-true, if you will. And basically, this is what we just always thought of as the monitor connection. Whenever you hooked up your monitor to your computer, it was the VGA connector. It was typically a 15 pin connection arranged in 3 rows of 5. And really, that was it. You plugged in your monitor and away you went. But VGA was an analog signal, so DVI is digital visual interface. And you may hear many people say digital video interface.
Close enough for day-to-day conversation, but as its name indicates, it was digital. But most people had analog monitors at the time that this came out, so you needed an adapter. So it didn't catch on all that much. Gamers tended to like it because it did offer faster refresh rates, and a little better quality. S-Video kind of relates to composite video, which is farther down the list. And this was essentially a combination, as the name indicates, for composite. It combined the brightness information, the resolution, and the color, all into a single connection, a single signal, so it didn't have very good quality. So S-Video never really caught on either. Now HDMI, certainly the standard today for most displays, TVs, of course, are almost all HDMI these days. That's High-Definition Multimedia Interface. So apart from the high definition, which is very nice, it's also multimedia so it can handle audio as well. And if you've ever connected a TV at home, you know that you only need the HDMI for both picture and audio. DisplayPort, as it's name indicates, was primarily used for display.
But like HDMI, it could also carry audio, USB, and other forms of data, but again, not all that common because HDMI caught on so quickly. Composite video, again, relates back to S-Video, and as its name indicates, it's composite, it's putting things together into a single signal. So again, the quality wasn't the best. But component video is the opposite, it's breaking things apart. So, simply, component broke apart the colors. You had three different connections for red, green, and blue, which are the component colors of video. That had HDMI specifications in terms of the resolution but it was only video. So again, HDMI caught on a lot more quickly than did component video. Now, in terms of batteries for laptops, these generally are quite replaceable. But you should always refer to the manufacturer's documentation to ensure that you get a compatible replacement. But they usually were very easy to replace.
There was usually just some kind of a latch mechanism, a little release that you would slide over and the battery would pop out. And then you just took it out and just popped in a new one. Certainly, make sure that you fully charge it before you initially use it, but most batteries, very replaceable. The CPU, again, depending on the manufacturer's specifications may determine whether you can or cannot upgrade. Again, in the desktop, this was a little more common simply because it was easier to access. But you may still be able to upgrade the CPU of a laptop, but certainly consult the documentation. Because, depending on the make and the model, it may require very specific configuration in terms of the physical socket. The cooling it requires, and the clocking, the cyclical value of processing.
Now, replacing an entire system board may be an option, but really consider replacing the entire unit before you replace the board itself. Replacing the system board can require an awful lot of work. Again, in a laptop, everything is so tightly packed together that you pretty much have to disassemble the entire unit to get the system board out. They're generally underneath all of the other peripherals and system components. So again, you almost have to disassemble the entire unit to get to the motherboard. So it might not be worth it. It might be cheaper to just replace the entire laptop, entirely. And that may also go for the power, or the DC jack. Replacing a failed DC jack may also require significant work because the existing one is probably soldered right to the system board. So you would have to de-solder the old one, and re-solder a new one. Which can, of course, cause damage if you apply to much heat to the wrong area.
So even though it's only one single little connector, this might just be worth replacing the entire unit if it does fail. And finally, the plastics and/or the frames for your laptops probably can be replaced. Again, check with the documentation. But the frame is the internal metal chassis whereby you mount all of the internal components to that frame. And this is typically measured by width, depth and height. And then of course, there's a plastic cover to close everything up and obviously make it look very aesthetically nice. But it is just plastic so it's a little more susceptible to scratches and dents and possibly even cracking. So it often can be replaced, but again, it does depend on the make and model. But the plastic cover itself is usually composite material, usually fairly strong. But lightweight, of course, so that it doesn't make the unit much heavier. And typically very durable, but not as resistant to cracks or breaks as the metal chassis is, so damage can still occur. But before you do anything in terms of replacing or upgrading the components of a laptop. Always consult the documentation before you make that call.
Types of Display
Now, in this presentation, we'll talk about various types of displays, beginning with the cathode ray tube, or CRT. And you may have heard many people refer to them as CRT monitors, and that is certainly correct, because it does contain a large cathode ray tube. Now, a cathode is essentially anything that caries or produces a negative electric charge. And that is exactly what happens with a CRT, it uses electrons and it literally fires them from a gun behind the screen. And electrons carry a negative charge. The electrons then strike the screen, or the sensor component of the screen, and it activates phosphors, which cause illumination. Now, they are becoming obsolete, they're large, they're bulky, they're heavy. So I don't think you'll find many CRTs around these days anymore. So then as a replacement, we started seeing the liquid crystal display, or LCD. And this of course, was very commonly used in laptop computers and then ultimately flat panel monitors.
And they certainly did produce a very clear image. And simply due to their size and their weight, they ultimately replaced the traditional CRT monitor. But there are several different variations in terms of the LCD display, a few different technologies, and each one has pros and cons. So we have in-plane switching, or IPS, super plane to line switching, or PLS, vertical alignment, or VA panel technology, and twisted nematic, or TN panel technology. Now, quickly going through each of those, in-plane switching typically is considered to have the best color accuracy and viewing angles and overall image quality of most LCD displays. But it does depend on what you are wanting to use it for.
Now, super plane to line switching was originally developed by Samsung, and it is very similar to IPS, the in-plane switching, but it tends to be a little bit brighter. Not a lot, maybe only by about 10%, but also claims to increase the viewing angle. So you may have noticed in looking at some LCD screens, if you move to one side or the other, you do start to lose some of the clarity of the image or perhaps the brightness. So PLS improved a little bit on those viewing angles. Then vertical alignment is somewhere in between the twisted nematic and the IPS. It does offer wider viewing angles and better quality, but it had slower response times. So this typically was not very good for anyone who was gaming, for example. So in fact, that leads to the twisted nematic. These ones did have a faster response time, making them the preferred choice for gamers. But they didn't have quite the range in terms of viewing angles and contrast ratios.
But gamers were almost always right in front of the screen, you know, they didn't really need to view it from an angle. So, again, each one had their pros and cons, and it really depended on what you were looking to do in terms of the choice. Now, one of the later technologies is organic light-emitting diodes, or OLED, and this is a very thin display technology that does not require any kind of backlighting. The OLED technology uses organic compounds to produce electroluminescence. So there are several layers as part of the screen from back to front. There's just the case, then a rear glass piece. And then a TFT, which is known as a thin film transistor. Then an anode, and that's the opposite of a cathode.
An anode produces a positive charge. Then we have the organic LEDs, and then we have the cathode. So the flow of current would go from the anode to the cathode through the organic LEDs, and that produced the light and the image. And then simply, a cover glass. Now, there were two different types within OLED, as well, passive-matrix OLED, which strictly uses the electroluminescent layer to light the screen. In other words, it does not use the TFT, which again, is that thin film transistor. The active-matrix OLED does use the TFT. But the problem here is that the organic compounds that produce the luminescence do tend to degrade over time. So with the active, this was a better choice for devices that aren't on all the time, such as your tablet or your phone.
Now, the phone may be powered on all the time, but the screen itself is off most of the time. So this, of course, can dramatically increase the life span of the display. But you would typically find that active-matrix OLED in the smaller devices, the phones, the tablets, and maybe not so much on a computer display.
Wi-Fi Antenna Connectors
These days, almost any laptop that you would buy would have built-in wireless capabilities. But some of the earlier models generally did not have that built in. So you needed some kind of adapter card that you would usually slide into the side so that it could Wi-Fi. But with it built-in, what you typically need in terms of any kind of wireless communication is antenna. And those older cards typically had a little section of it, if you will, that was allocated to hold an antenna. So if the wireless is built-in to the laptop, well, where is the antenna? We don't see any kind of telescoping antenna that we can pull out, but there is one in there.
[Video description begins] Wi-Fi Antenna. [Video description ends]
And most often it's wrapped around the laptop display screen. It really doesn't need to be much more than a wire, but you can wrap it around as many times as you want. But really, anything that will pick up on electromagnetic waves can be used as an antenna. And by placing the cable around the frame, it can better withstand the constant opening and closing of the screen. So that makes it a little more durable and less susceptible to breaking. But now in terms of performance, it is enclosed within the device. Now, that typically doesn't cause too much trouble because the outer casing is usually just plastic. Which is easily penetrable by the electromagnetic waves. But the performance can be improved if it's located in the top part of the lid. Basically, this gets it up a little bit higher.
And generally, that gets you a little less interference, if you will. There maybe is better line of sight to the wireless access point. But overall, you can get a little bit better range and a little bit better performance. So ideally, the antenna should be placed in the uppermost portion of the lid just to get it as free as possible from everything else. But most notably, if it's down at the bottom, then the signal is probably being blocked by the rest of the laptop itself. All of the components that are in the lower portion, the keyboard and all of the electronics, the motherboard, all of that. So again, ideally at the uppermost portion of the lid will get you your best performance.
Webcams and Microphones
Now the next component we'll take a look at in this presentation is the WebCam. And this is certainly most commonly used for Internet video communication. So just chatting with someone, or maybe even video conferencing. But in terms of the performance considerations, what you would want to know would be the image quality, which is measured in pixels. And this would be the same as for a digital camera or the camera in your phone. It's going to be a megapixel value. And at least 2 million pixels or 2 megapixels is enough to essentially provide 1080p high definition resolution. But the other consideration is the frame rate, because we aren't just talking about taking still pictures here.
So the frame rate is taking multiple pictures per second. So the more pictures you can take per second of something that is moving, then the smoother the video is. So a frame rate of 30 frames per second is considered to be best, but the problem with high quality and high frame rate is that it produces more data. So if you are trying to just video chat with someone, and you don't have a very good link between you in terms of the network. Then this can kind of backfire. You send too much data over the link and it just gets bogged down. So depending on the circumstances, you might want to actually bring these values down a little bit. And most applications do allow you to configure those values so that they can be taken down in those cases. Now, if you don't have one built-in, a USB webcam is a good option.
Most newer laptops would have one built-in, but again, some older ones don't. And of course, if you have a desktop it wouldn't be built-in at all, although some standalone monitors these days do have webcams built-in, as well. But, of course, the benefits are portability. You can detach it from any system and attach it to any other system. It's very compatible. They don't need very many drivers. In most cases, they'll be picked up automatically. And they tend to have a few different attachments, as well. Meaning that they can usually stand on a little tripod, or they can maybe even hang from the top of your screen. Now, along with the video, we typically want audio as well.
[Video description begins] Microphones. [Video description ends]
So most laptops that have a webcam also have a microphone. Now, they're usually very small in size, and typically placed in the top of the laptop. Maybe down toward the bottom, again depending on the make and model. But this does make video chatting a little more natural compared to an external microphone. Because you don't have to hold a microphone up to your mouth. But since it's a little farther away, they need to be more sensitive. So they pick up a lot of extra noise, as well, and the quality really isn't all that good with the built-in microphones. So there are alternatives to that of course whereby you can get a USB microphone. Again, very portable, easy to connect.
[Video description begins] Computer headphones. [Video description ends]
And perhaps the best quality is a headset of some kind, it's adjustable and portable. And of course the microphone is very close to your mouth so it doesn't need to be as sensitive as the built-in one. And typically they just provide much better quality anyway.
Inverters
Now, in this presentation, we'll talk about some lighting technologies that are used for flat screens. Both standalone monitors and in laptops. And we'll also touch on what's known as an inverter, but we'll come back to that in a moment. We'll begin with the Cold Cathode Fluorescent Light or CCFL. This is a lighting technology commonly used in LCD monitors, neon signs, and perhaps computer case lighting. But LCD monitors did not produce their own light just by using the liquid crystal display. They needed an additional backlighting source and that was the CCFL. That basically is the same as the fluorescent lights you might see in the ceiling of an office building. They are the long tubes of light. Now, the reason why I mentioned an inverter is because the power that usually feeds a laptop is DC, direct current.
But fluorescent lights need AC, alternating current. So if you had a CCFL providing the backlight then you needed an inverter built in as well. So for every CCFL that you had, you needed another inverter. So this tended to make them heavier, okay? And they use more power than LEDs, which we'll talk about in a moment. Now, most screens could get by with just a single CCFL, depending on how large they were. Then there was usually just a diffuser screen to make it seem like the light was even everywhere. And again, if you think about the lights in the ceiling, there was almost always some kind of a diffuser screen to spread it out. And it was typically located either in the bottom or the top of the screen itself, but possibly in both. And possibly even more than two, it really depended on the make and model.
But for every CCFL you had, you needed another inverter. So if you had to, well then it's going to add twice as much weight with the extra tube and the extra inverter. So the small tube usually was still able to provide ample lighting, while also not rising the ambient temperature above what it might be otherwise. CCFLs don't tend to run all that hot, so that at least was one nice feature. This would prevent damage to any component that, of course, might be just close in terms of proximity to the actual tube itself. But along came LED, light emitting diodes. And this is a semiconductor device that emits visible light. And commonly used in LCD panel backlighting.
But also in fiber optic data transmission and indicator lights, really, on a number of different types of devices. But in terms of benefits, they have a lower power requirement, because there's no inverter required. They're very efficient, they have minimal heat production. There's a very long life associated to LEDs, and a very good quality as well. So these are becoming much more common these days. Most newer screens that you would buy would likely be LED, versus LCD. And again, it's probably going to be much lighter because there's no inverter when you have an LED screen.
Touchscreens
In this presentation, we'll take a look at digitizers, which really is any type of device that can produce a digital result from a non-digital input. So some common examples include a stylus, whereby you have some kind of a pen type of device or even your finger to determine the positioning. So quite simply, we provide analog information. We just draw on the screen, and that can be literally anything. From that input, a digitizer will produce digital results that, of course, can be processed by the system. So tablets and smartphones are, of course, perhaps the most common example of digitizers. Both can be control by a pen or perhaps, these days more commonly, just your finger.
But you can draw or write directly on the screen, and again, that can be anything, any kind of motion. So of course, these days tablets and smartphones are very good examples of digitizers. Both devices are controlled by a pen or by your finger, and users can draw or write directly on the screen. And that is then simply converted into digital information that the system can process appropriately. Now, touchscreens also count. Again, there are different types of sensing mechanisms for picking up where you touch the screen. But it is still some kind of analog input that we are providing that needs to be converted into digital information. So the touch screen, again, very common in scenarios where a keyboard and a mouse just really isn't viable or convenient, such as an information kiosk or a point of sale system.
Now, there are two types of touch screens, the built-in, which again, is something like your smartphone or your tablet, or a complete standalone system, such as a kiosk or a point of sale system. It's designed specifically for just that particular system and maybe even just a particular type of application on that system. So again, it's a little more dedicated, but of course, again, we're all familiar with controlling our smartphones and tablets just by using our fingers. And again, of course, a multitude of applications on the smartphone or the tablet can all receive those analog inputs and still produce digital information from that, which can be processed by the system.