Display Specifications – CompTIA A+ 220-901 – 1.10

| December 4, 2015 | 0 Comments

If you’re designing a computer system, you’ll need to choose the right display. In this video, you’ll learn about the most important display specifications to consider when picking out a monitor.

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When working with displays, there are a number of characteristics that you should know about. And in this video, we’ll look at some of the most common display specifications.

Back in the days of cathode ray tubes, an electron beam would constantly update the information in the phosphor on these tubes. This screen would be updated a number of times a second. And we call this a refresh rate because it had to constantly refresh that phosphor. This would also be referred to in hertz. This would be the number of times in a second that a screen was redrawn.

With LCD screens, of course, there is no electron beam. We don’t have to constantly refresh any phosphor, but we still use this term hertz to describe the refresh rate. But with LCD displays, the screen is simply changed. We don’t have to paint the screen, or change the screen one part at a time. We can change everything on the screen instantly. But we still refer to this refresh rate in hertz to describe how many times this particular screen can possibly update during a single second. So it’s not unusual to see LCD displays with 60 hertz, 120 hertz, or even 144 hertz response times.

Another important characteristic of a display is the resolution. This describes just how many pixels are available to view on that particular display. We describe this as the number of pixels along the width, times the number of pixels along the height. This is also referred to as the aspect ratio, where we’re looking at the difference between the width and the height of the display. Some of the traditional standard monitors were a 4:3 aspect ratio, which meant that we have resolutions of 1600 in the width, and 1200 in the height. Might also see 2048 x 1536. So the numbers might be a little bit different with the resolutions, but the aspect ratio always stayed the same.

Another common aspect ratio that we see on displays is 16:10. This would be a resolution of 1920 x 1200, or 2560 x 1600. And perhaps one of the more common aspect ratios, especially for our televisions, is a 16:9. We sometimes refer to this as the HD resolutions, or the HD ratio. This is 1920 x 1080, or 2560 x 1440.

The number of pixels that is on one of these LCD displays is obviously a fixed number. There are a certain number of pixels in the width and a certain number of pixels in the height. This number is obviously a fixed number and it doesn’t change depending on how you configure the display. The display is going to look best if both of those numbers are identical.

If you use a different resolution, your display is going to attempt to show that resolution on the screen, but because the pixels don’t match up exactly, you will see a bit of distortion. This is picture that shows what a distortion of that might look like. You can see an example of the distortion. The r that’s on this line is different than the r that is on this line. And that difference is caused by the monitor trying to adjust for that difference in non-native resolution.

If you do need to change the resolution on an LCD display, try using a resolution that is exactly the same aspect ratio. So if you’re running a 2560 x 1600, and you’d like to change the resolution, try something like 1920 x 1200, where you have exactly the same aspect ratio between both of those resolution types.

The brightness of a display is an important characteristic. We refer to this as the luminance of the display, and it’s usually measured as candela per square meter, or abbreviated cd/m squared. In most cases, a brighter monitor is going to be a better looking monitor. Another measurement of brightness is lumens. This is an ANSI standard test, and 3,000 lumens would mean that the monitor would look very good in a dim room. If you’re getting 6,000 lumens out of a display, it will work very well even in a sunlit room.

Our display signals can be transmitted in either an analog or a digital format. The analog format is transmitted as one continuous signal, and you’ll usually see analog being used over a VGA connection. And there are some DVI connections that support analog connectivity. A digital signal is being sent by a discrete value, either a one or a zero. And this is often sent over a DVI cable that’s running a DVI-D– D is for digital– or HDMI, which is the High Definition Multimedia Interface. And all of the signal sent over HDMI will always be digital.

If you have a laptop computer, you may want to take advantage of some display filters. One common filter, especially when traveling, is a privacy filter. This is one where you can put a filter over the display, and you’re not able to view that display unless you are directly in front of it. If you’re off to the side, you’re either going to see a completely black color or gold color, depending on the filter that you use. It’s very common to see this, especially on planes, where you can sit right next to someone on a plane and not see anything on their display.

A lot of our laptop displays have very glossy screens, which are great for color reproduction, but they’re also great for reflections and glare. So you can get an anti-glare filter to go on top of your display, and that will reduce the glare coming across it. Make it easier to use, especially in a very bright or well lit area.

Having multiple displays on your computer can really improve the efficiency of how you use your work environment. You’re able to have different things on different displays and be able to use them simultaneously. There are two different settings in your operating system. One is to extend the desktop between the two displays, and you can simply move your mouse left and right between those two displays to work on them. You determine what display is on the left and what display is on the right in the operating system configuration for those displays.

You might also want to configure your second screen to be mirrored. That way you would see on the second screen exactly the same thing that’s on the screen in front of you. This is especially useful for presentations, when you want to be sure that you’re viewing exactly what the audience sees.

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Category: CompTIA A+ 220-901

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