The CRT monitors use a cathode ray tube to display images. The distinct feature of these monitors is that they resemble a television set. The cathode ray tube, which is made of glass and metal, is a vacuum inside. The monitor's screen is coated with phosphorous from the inside. When the electrons are produced inside the cathode ray tube, the screen is bombarded with the electrons, making it glow and producing an image. The CRT monitors are heavy, bulky and consume a lot of electrical power.
LCD technology was first used in laptops before advances were made to make the switch to computer monitors. LCD monitors use liquid crystal display to exhibit images on the screen. Unlike its bulky counterpart the CRT monitor, the LCD monitor is usually a thin and flat panel visual display unit. Images on the LCD monitor are created by manipulating the layer of liquid crystals using varying degrees of voltage. LCDs are power-conserving devices and can even run on battery power.
PDP monitors use the technology of gas discharge to display pictures and images on the screen. The PDP produces ultraviolet rays through utilization of an external voltage causing gas discharge. The PDPs are the most technologically advanced of the monitors and therefore produce high quality images. Power consumption of PDPs is largely dependent on the quality of image produced. Bright images or scenes draw more power than dark ones.
Apart from the three major categories of computer monitors, there is also the TFT type. This type of computer monitor uses a thin film transistor to display images and is a modification of the LCD monitor.