Component refers to 'component analogue' and is a type of video signal and connections. Unlike a composite video signal which combines the luminence and the colour information into one RF (radio frequency) signal and one connection, component splits the video into parts which are carried separately in three RF signals (3 connections). The 'Y' signal carries only the luminence and sync information, and a black & white picture (as if a composite signal minus colour) can be seen if only this is used. The colour information is carried as 'R-Y' (red minus luminence), and 'B-Y' (blue minus luminence). The green signal is recreated by clever maths within the machine or monitor because it has the other values (a bit like trigonometry). Odd colour effects result from connecting these signals the wrong way round. See also S-video/YC.