Friday, December 21, 2007


A liquid crystal display (LCD) is a thin, flat display appliance made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very little amounts of electric power, and is therefore suitable for use in battery-powered electronic devices. In color LCDs each individual pixel is separated into three cells, or subpixels, which are coloured red, green, and blue, respectively, by additional filters. Each subpixel can be controlled independently to defer thousands or millions of possible colors for each pixel. Older CRT monitors employ a similar sub pixel structures via the use of phosphors, although the analog electron beam employed in CRTs do not hit correct subpixels.

Color components may be arrayed in a range of pixel geometries, depending on the monitor's usage. If software knows which type of geometry is being used in a given LCD, this can be used to increase the evident resolution of the monitor through subpixel rendering.

Monday, December 17, 2007


A gear is a wheel with teeth around its circumference, the purpose of the teeth being to mesh with similar teeth on another mechanical device possibly another gear wheel so that force can be transmitted between the two strategies in a direction tangential to their surfaces. A non-toothed wheel can transmit some tangential force but will slip if the force is large; teeth put off slippage and permit the transmission of large forces.

A gear can mesh with any device having teeth friendly with the gear's teeth. Such devices include racks and other non-rotating policy; however, the most common condition is for a gear to be in mesh with another gear. In this case revolution of one of the gears necessarily causes the other gear to rotate. In this way, rotational motion can be transferred from one position to another. While gears are sometimes used simply for this reason to transmit rotation to another shaft perhaps their most significant feature is that, if the gears are of asymmetrical sizes, a mechanical advantage is also achieved, so that the rotational speed, and torque, of the second gear are dissimilar from that of the first. In this way, gears provide a means of increasing or decreasing a turning speed, or a torque.