Quote:
Originally Posted by Don Lindsly
The yoke is wound to achieve the desired deflection angles, both vertical and horizontal. You will notice the difference between a 90 and 70 degree yoke.
The second consideration is impedance. The yoke must match, or at least be close, to the design impedance of the flyback and vertical output transformer. That assures maximum energy transfer from the output circuits to the yoke. A mismatch will show up as non linearity, drive lines and/or distortion.
The third is the available output stage power. A 90 degree yoke will not always deliver enough width and height without the additional power necessary to sweep the sharper angle.
There is some consistency within manufacturers, but not always. It is best to match the correct yoke and only use a substitute for testing.
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This is starting to help but I'm afraid I'm going to show the depth of my ignorance.
The deflection should probably be linear with current. But as the beam travels a longer distance through the field at larger deflection angles it would start to be bent more than would be proportional to the current. So, they must wind it so that the field drops off more rapidly at larger angles? What do they mean by cosine wound? Is that related to the above?
The impedance must be complex. Nearly purely inductive so wouldn't the power factor be zero?
The field would be determined by the number of amp turns. The inductance would probably go as the number of turns squared. I would think that you would want the inductance as low as possible while keeping the amperage reasonable. So that the yoke would look like a low reactive impedance and the power actually being dissipated in a load resistor. That is the reactive impedance would be small compared to the load resistor.
Is my thinking going wrong somewhere here?
John