<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (April 2008) (Learn how and when to remove this template message) </Td> </Tr> <P> The refresh rate (most commonly the "vertical refresh rate", "vertical scan rate" for cathode ray tubes) is the number of times in a second that a display hardware updates its buffer . This is distinct from the measure of frame rate . The refresh rate includes the repeated drawing of identical frames, while frame rate measures how often a video source can feed an entire frame of new data to a display . </P> <P> For example, most movie projectors advance from one frame to the next one 24 times each second . But each frame is illuminated two or three times before the next frame is projected using a shutter in front of its lamp . As a result, the movie projector runs at 24 frames per second, but has a 48 or 72 Hz refresh rate . </P> <P> On cathode ray tube (CRT) displays, increasing the refresh rate decreases flickering, thereby reducing eye strain . However, if a refresh rate is specified that is beyond what is recommended for the display, damage to the display can occur . </P>

In lcd the refresh rate of the screen is