Television steering coil control circuit

[learningphysics]

Hi. I'm trying to find information about the circuit which controls raytracing within a television CRT tube (the circuit which controls the current through the steering coils deflecting the beam up down left and right)... How is this precise raytracing accomplished... what type of circuit is involved?

[Dngrsone]

It's a sawtooth generator, actually two of them-- the horizontal and vertical. The horizontal sawtooth slope will cause the beam to move from one side to the other and the return line performs retrace. Same type of thing with the vertical, except the frequency is a lot smaller. IIRC, most sets actually use a stepped sawtooth for the vertical so the horizontal scan is even, otherwise your lines will tilt downward from the left to the right.

There are timing pulses between frames to synchronize the sawtooths so you get smooth video. The vertical and horizontal holds are there to tweak the signal generators to the incoming signal.

Hope this helps.

[learningphysics]

That helps a lot! Thanks!

[Dngrsone]

BTW, linkage:

http://www.ee.washington.edu/conselec/CE/kuhn/ntsc/95x4.htm

It was hiding in plain sight in my Favorites folder.