How Computer Monitors Work

How Computer Monitors Work?

A computer Monitor is a fascinating thing. A seemingly ordinary dark gray surface can suddenly morph into an artist’s canvas, an engineer’s gauges, a writer’s page or your very own window to both the real world and a vast array of artificial worlds!

 Because we all use them daily, many of us have a lot of questions about our displays and may not even realize it. 

1->What does “aspect ratio” mean? 

2->What is dot pitch? 

3->How much power does a display use? 

4->What is the difference between CRT, and LCD? 

5->What does “refresh rate” mean?

 In this edition of Peoplelaptop, we will answer all of these questions, and many more. 

In this article, you will not only understand your current display but also feel empowered to make better decisions about purchasing your next one, armed with the knowledge of how display technology works.

The Basics

Frequently known as a monitor, when housed in its own enclosure, the display is the most commonly utilized output device on a computer. Imagine working on a document or playing a game without being able to see what you’re doing- that’s the importance of a display. Most desktop displays use a cathode ray tube (CRT).

At the same time, portable computing devices such as laptops incorporate liquid crystal display (LCD), light-emitting diode (LED), gas plasma or other image projection technology. Because of their slimmer design and smaller energy consumption, monitors using LCD technologies are beginning to replace the venerable CRT on many desktops.

 When purchasing a display, you have a number of decisions to make. These decisions affect how well your display will perform for you, how much it will cost and how much information you will be able to view with it. Your decisions include:

  1. Display technology – Currently, the choices are mainly between CRT and LCD technologies.
  2.  Cable technology – VGA and DVI are the two most common.
  3.  Viewable area (usually measured diagonally)
  4.  Aspect ratio and orientation (landscape or portrait)
  5.  Maximum resolution
  6.  Dot pitch
  7.  Refresh rate
  8.  Color depth
  9.  Amount of power consumption

 In the following sections, we will discuss each of these areas so that you can completely understand how your monitor works!

Types of Computer Monitors

LCD Monitors

LCD (Liquid Crystal Display) monitors are one of the most common types found today. They utilize a layer of liquid crystal solution sandwiched between two layers of glass. When an electric current passes through the liquid crystals, they align to allow or block light, producing images on the screen.

LED Monitors

LED (Light Emitting Diode) monitors are a variation of LCD monitors. Instead of using fluorescent tubes for backlighting, LED monitors use light-emitting diodes, offering better energy efficiency, brightness, and contrast ratios.

OLED Monitors

OLED (Organic Light-Emitting Diode) monitors are known for their superior picture quality and thinness. Each pixel in an OLED monitor emits its own light, allowing for true blacks and vibrant colors without the need for a backlight.

Components of a Computer Monitor

A typical computer monitor consists of several key components:

Display Panel

The display panel is where the magic happens. It’s composed of numerous pixels, each capable of displaying different colors and shades. Different types of display panels determine factors like response time, color accuracy, and viewing angles.


The backlight illuminates the display panel, allowing the images to be visible. Depending on the monitor type, backlights can be fluorescent tubes (in older LCD monitors) or LEDs (in modern LCD and LED monitors).


Connectors are the interfaces through which the monitor communicates with the computer. Common connectors include HDMI, VGA, and DisplayPort, each offering different levels of bandwidth and compatibility.

 Display Technology

 Displays have come a long way; since the blinking green monitors in text-based computer technology systems of the 1970s. The evolution of display technology is a fascinating journey that has led us to the advanced displays we use today. 

Just look at the advances made by IBM over a decade:

In 1981, IBM unveiled the Color Graphics Adapter (CGA), which is capable of displaying four colors with a maximum resolution of 320 pixels horizontally by 200 pixels vertically.

Three years later, in 1984, IBM introduced the Enhanced Graphics Adapter (EGA) display. EGA enhanced the color palette to 16 different colors and increased resolution to 640×350 pixels, significantly improving display quality and text legibility.

In 1987, IBM launched the Video Graphics Array (VGA) display system, which has become a standard in most computers today. Many VGA monitors are still in active use.

IBM continued its display innovations by introducing the Extended Graphics Array (XGA) display in 1990. XGA offered resolutions of 800×600 pixels in true color (16.8-million colors), and 1,024×768 resolution in 65,536-colors.

Most displays sold today support the Ultra Extended Graphics Array (UXGA) standard. UXGA can support a palette of up to 16.8 million colors and resolutions of up to 1600×1200 pixels, depending on the video memory of your computer’s graphics card. To put this into perspective, the maximum resolution normally depends on the number of colors displayed. For example, your card might require that you choose between 16.8 million colors at 800×600 or 65,536 colors at 1600×1200.

 A typical UXGA adapter takes the digital data sent by application programs, stores it in video random access memory (VRAM) or some equivalent, and uses a digital-to-analog converter (DAC) to convert it to analog data for the display scanning mechanism. Once it is in analog form, the information is sent to the monitor through a VGA-cable. In simpler terms, the adapter translates the digital information from your computer into a format that your monitor can understand and display.  

See the diagram below:

This VGA connector features three distinct lines for the green, red, and blue color signals, and two lines for horizontal, and vertical sync signals. Unlike a standard television, where these signals are merged into a single composite video signal, the separation of signals allows a computer monitor to accommodate significantly more pixels than a TV set. In simpler terms, this means that your computer monitor can display more detailed and vibrant images than a TV.

 Since today’s VGA adapters do not fully support the use of digital monitors, a new standard, Digital Video Interface (DVI), has been designed for this purpose. Because VGA technology requires that the signal be converted from digital to analog for transmission to the monitor, a certain amount of degradation occurs. 

DVI maintains data in digital format from the computer to the monitor, effectively eliminating signal degradation. It utilizes Silicon Image’s Transition Minimized Differential Signaling (TMDS) to establish a high-speed digital connection. TMDS, originating from the graphics adapter, identifies the monitor’s resolution and refresh rate and then efficiently spreads the signal across the bandwidth to enhance data transmission between the computer and the monitor. In simpler terms, DVI ensures that the image you see on your monitor is as clear and accurate as possible.

 DVI is technology-independent. This means that DVI is going to perform properly with any display and graphics card that is DVI compliant. If you buy a DVI monitor, make sure that you have a video adapter card that can connect to it.

Power Consumption

Power consumption varies greatly with different technologies. CRTs are somewhat power-hungry, at about 110 watts for a typical display, especially when compared to LCDs, which average between 30 and 40 watts.

 In a typical home computer setup with a CRT-based display, the monitor accounts for over 80 percent of the electricity used! But don’t worry, because most users only interact with the computer a little of the time it is on, the U.S. government initiated the Energy Star program in 1992. 

Energy Star-compliant equipment monitors user activity and suspends non-critical processes, such as maintaining a visual display until you move the mouse or tap the keyboard. According to the EPA, if you use a computer system that is Energy Star compliant, it could save you approximately $400 a year on your electric bill! Similarly, because of the difference in power usage, an LCD monitor might cost more upfront but end up saving you money in the long run.

 CRT technology is still the most prevalent system in desktop displays. Because standard CRT technology requires a certain distance between the beam projection device and the screen, monitors employing this type of display technology tend to be very bulky. Other technologies make it possible to have much thinner displays, commonly known as flat-panel displays.

Liquid crystal display(LCD) technology blocks light rather than creates it while light-emitting diode(LED) and gas plasma technologies light up display screen positions based on the voltages at different grid intersections. LCDs consume significantly less energy than LED and gas plasma technologies, making them the predominant choice for notebooks and other portable computers. With advancements in screen size, resolution, and cost-effectiveness, flat-panel displays are steadily replacing CRT-based displays.

Connecting a Monitor to a Computer

Connecting a monitor to a computer is a straightforward process that typically involves using one of the following connectors:

  • HDMI: High-Definition Multimedia Interface, commonly used for connecting modern monitors to computers, gaming consoles, and other multimedia devices.
  • VGA: Video Graphics Array, an older analog standard still found on some monitors and computers.
  • DisplayPort: A digital display interface known for its high bandwidth and versatility, capable of supporting multiple monitors and higher resolutions.

Setting up a Monitor with a Laptop

Many users prefer to enhance their laptop experience by connecting it to an external monitor.

Setup offers benefits like:

  • Increased Screen Real Estate: Working with multiple windows simultaneously becomes more manageable with a larger screen.
  • Better Ergonomics: Positioning the laptop screen at eye level while using an external monitor can reduce neck and eye strain.

Connection Methods

Setting up a laptop with a monitor typically involves connecting them using one of the previously mentioned interfaces and configuring the display settings on the computer.


Computer monitors play a crucial role in our digital lives, providing us with visual access to the vast world of information and entertainment. Understanding how monitors work and how to choose the right one for your needs can significantly enhance your computing experience.


Do all monitors support the same resolutions?

No, monitors come in various resolutions, ranging from standard definition to ultra-high definition, so it’s essential to choose one that meets your requirements.

Can I use a monitor as a TV?

Yes, many modern monitors come with built-in speakers and HDMI ports, making them suitable for use as a TV with the addition of a streaming device or cable box.

What’s the difference between HDMI and DisplayPort?

While both HDMI and DisplayPort are capable of transmitting high-definition audio and video signals, DisplayPort generally offers higher bandwidth and supports features like multi-stream transport (MST) and daisy-chaining.

How do I know which monitor is compatible with my computer?

Check your computer’s graphics card outputs and compare them to the inputs on the monitor. Most modern computers and monitors support HDMI, DisplayPort, or both.

Are curved monitors better than flat monitors?

Curved monitors offer a more immersive viewing experience and can reduce eye strain by minimizing distortion at the edges of the screen. However, whether they’re better than flat monitors depends on personal preference and specific use cases.

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