The image on an LCD television's screen is the result of two primary components: a backlight and an arrangement of liquid crystals. When you turn on your LCD TV, a backlight activates in the rear of your TV set. As long as the TV is on, this light is on, which is why you can see an LCD screen's outline in a dark room even if there is no picture. When your LCD TV gets a video signal, it sends out electrical impulses to the liquid crystals in the screen. The crystals change shape and allow the backlight's light to pass through according to what electrical impulses they receive.
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