Furthermore, wide-deflection-angle CRTs need horizontal sweeps with current that changes proportionally faster toward the center, because the center of the screen is closer to the deflection yoke than the edges.
12.
Electronically, the inductance of the deflection yoke's vertical windings is relatively high, and thus the current in the yoke, and therefore the vertical part of the magnetic deflection field, can change only slowly.
13.
It uses a wide-angle electrostatically-deflected CRT that is about as compact as a magnetic-deflection CRT . Instead of the deflection plates of a typical CRT, it has a unique structure called an electrostatic deflection yoke, with metallized electrodes inside a glass cylinder.
14.
In electronics, these ( usually steady-rate ) movements of the beam [ s ] are called " sweeps ", and the circuits that create the currents for the deflection yoke ( or voltages for the horizontal deflection plates in an oscilloscope ) are called the sweep circuits.
15.
That axis is perpendicular to the neck of the tube; lines of force are basically horizontal . ( In detail, coils in a deflection yoke extend some distance beyond the neck of the tube, and lie close to the flare of the bulb; they have a truly distinctive appearance .)
16.
However, the entire structure of the cathode, deflection yokes, anode and overall vacuum tube size is much larger, therefore made out of steel, not glass, with the main central open midsection of the vacuum tube hollow, leaving room for the scan table and object or person to lie while the scan is performed.
17.
The solution to the static convergence and purity problems is a set of color alignment magnets installed around the neck of the CRT . These movable weak permanent magnets are usually mounted on the back end of the deflection yoke assembly and are set at the factory to compensate for any static purity and convergence errors that are intrinsic to the unadjusted tube.
