For LCD monitors the pixel brightness changes are much slower than CRT or plasma phosphors. Plasma screens use significantly more energy than CRT and LCD screens. LCD monitors are typically sharper, brighter, and more economical than CRT monitors. LCD, LED, plasma and CRT (picture tube) color video displays all use this method. Apple Inc. sold a variety of LCD and CRT computer displays in the past. This is particularly true of aircraft equipped with electronic displays (CRT or LCD). Peak lumens is a measure of light output normally used with CRT video projectors. Dixons ceased selling CRT televisions in 2006. The VHS version is formatted with 4&colon;3 aspect ratio, common for CRT television sets. In 2005, Sony announced that they would stop the production of CRT computer displays. These types of display screens use lower voltages than older CRT displays. These machines were AC powered and included a small CRT display screen. These values reflect the approximate color of consumer CRT phosphors. The production of plasma and CRT displays has been almost completely discontinued. The horizontal and vertical oscillators form the raster on the CRT.