Channel: itfreetraining

Category: Education

Tags: oledmvatna+ipsitfreetrainingmonitors

Description: In this video from ITFreeTraining I will look at monitors. Monitors essentially display a picture that allows you to know what is going on inside the computer. There are three basic types of monitors, flat-panel monitors, projectors and virtual reality headsets. This video will look at flat-panel monitors and I will leave the rest for another video. Download the PDF handout: itfreetraining.com/handouts/ap/2a10.pdf Cathode-Ray Tube (CRT) 0:23 Before I start looking at flat-panel monitors, I will first have a very quick look at CRT monitors. I say quickly because for the CompTIA exam you really only need to know that CRT monitors contain toxic waste and thus need to be disposed of correctly. This means disposing of a CRT monitor in an e-waste facility, not just sending it to land fill. CRTs are big and bulky compared with flat-screen monitors and thus less preferable. In 2008 flat-panel displays exceeded CRT sales. The last CRT was manufactured in 2015. If you do come across one in the workplace, you will most likely be asked to dispose of it. Now to the main topic of the video. Liquid-Crystal Display (LCD) 1:07 The liquid crystal display, or LCD, has become the most used and sold monitor on the market. There are a few different types, but before I start looking into that I will first look into how they work. You don’t need to know too much about how LCDs work for the CompTIA exam, but having a basic understanding of LCDs will help you understand what you can expect to achieve out of them and their limitations. An LCD screen essentially starts with a light source. There are a few different ways this can be done, but for the present let us just consider this is at the back of the monitor creating light. The light goes off in every direction. When the light is distributed in different directions it is also distributed in different wave forms. I will spare you a big physics lesson, but essentially what happens is a filter is placed in front of the light source. This filter blocks some of the waves but not all. Essentially, what is going through the filter is light of all the same wavelength. The filter is placed so it is horizontal. To understand why, I will skip ahead a little bit. Towards the end of the process, there is a second filter. This filter is essentially the same as the first however it is rotated 90 degrees. Since the filter is rotated, this means it will block any light allowed through by the first one. You may be wondering why you would have two filters that block all the light that travels through; however, it will start making more sense soon. In the middle of the process there is a layer of liquid crystal, and this is where its name comes from. When light passes through it, it will travel through but will not be altered. However, if electricity is applied to it the liquid crystals this will change the wavelength of the light traveling through it. Depending on what wavelength is when it hits the second filter it will either be allowed or blocked. Description to long for youtube. For the rest of the description please go to itfreetraining.com/ap/2a10 References “The Official CompTIA A+ Core Study Guide (Exam 220-1001)” Chapter 4 Position 250 - 847 “CompTIA A+ Certification exam guide. Tenth edition” Pages 737 – 750 “Cathode-ray tube” en.wikipedia.org/wiki/Cathode-ray_tube “Liquid-crystal display” en.wikipedia.org/wiki/Liquid-crystal_display “Twisted nematic field effect” en.wikipedia.org/wiki/Twisted_nematic_field_effect “Picture: Light blub” pixabay.com/illustrations/light-bulbs-light-bulb-light-energy-1125016 “Picture: TV Backlight” en.wikipedia.org/wiki/File:LCD-TV_Backlight_with_CCFL.jpg “Picture Lamp Driver: ” commons.wikimedia.org/wiki/File:2007-09-02_CCFL_lamp_driver.jpg “Picture: TN-LCD-schematic-MS-208kB.png ” commons.wikimedia.org/wiki/File:TN-LCD-schematic-MS-208kB.png “OLED” en.wikipedia.org/wiki/OLED “Video: British short hair cat” pixabay.com/videos/cat-british-shorthair-chocolatepoint-3740 “Pixel density” en.wikipedia.org/wiki/Pixel_density “Dot pitch” en.wikipedia.org/wiki/Dot_pitch “Picture: CRT mask types en-de.svg” commons.wikimedia.org/wiki/File:CRT_mask_types_en-de.svg “Picture: Holding mobile phone” unsplash.com/photos/jzZMvKChCx4 “Picture: Forest” unsplash.com/photos/RwHv7LgeC7s “Video: Wine turbines” pixabay.com/videos/wind-mill-energy-wiek-wind-turbine-13238 “Color vision” en.wikipedia.org/wiki/Color_vision “Active Matrix Liquid Crystal Displays: Fundamentals and Applications: Page 158” books.google.com.au/books?id=EdEzJYJFyU0C Credits Trainer: Austin Mason ITFreeTraining.com Voice Talent: HP Lewis hplewis.com Quality Assurance: Brett Batson pbb-proofreading.uk