well active matrix plays the matrix as your screen saver :o j/k
anyway an active matrix display has a transistor for each pixel there is on the screen. that translates in better image quality, faster refreshes, better contrast, and require a lot of power to operate/
a passive matrix has a transistor for each line on each axis. the image quality is not that good, but they require less power that's why they are the top choice in portables. They require a lot of cleaning too to keep the image sharp.
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