Asked by
Naveen Misra
in
Electronics & Gadgets
at
9:20 AM on February 03, 2009
Santosh Kuma's Answer
A raster is the trace of the electron beam in a TV tube that makes up the image. It starts at the top left of the screen, and draws a line to the right, then returns to the left, slightly lower and draws the next line. When the very bottom line has been drawn, the lelctron beam will return to the top and start again. This pattern is called a raster.
A raster circuit generates a ramp voltage or current to deflect the beam inside the tube from left to right, with a very fast return to the left to start again. At the same time, a similar circuit generates a slower ramp to deflect the beam from the top to the bottom of the screen. Together, these two parts make a complete raster curcuit.
This is a simplified explanation and a web search will produce results of more detailed explanations.
Answered at
9:24 AM on February 03, 2009
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