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11-7 Ray deflection process to scan the screen:

There are two ways to direct the deflection of the ray from the left of the screen towards the right of it and vice versa. From top to bottom and vice versa:

1 - Electrostatic deviation

2- Deviation using the electromagnetic method.

1- Electrostatic deviation:

It is done by the influence of two opposite horizontal plates - and others vertical - inside the screen, where the electronic beam passes between them (Fig. On all TVs. This is because the TV screen requires a large beam angle of deviation of up to (5114) while this angle does not exceed (40-550) in the signal oscilloscope - the electrostatic method requires high efforts in the panels and in the elevator
screen to accelerate the beam, it reaches 30 kV in the television set, while in the signal oscilloscope it is about 1 kV.

2- Electromagnetic deviation:

Magnetic deflection is done by files called deflection files surrounding the neck of the screen and consists of horizontal deflection files and vertical deflection files.

The magnetic fields of the coils move the beam horizontally and vertically. It is fed with a current that has a wave from the saw, generated by the horizontal and vertical deflection circuits.

The horizontal deflection files consist of two opposite pairs of files, and they are placed vertically on the neck of the screen. Among them are the vertical deflection profiles, which are of two opposite pairs, they are placed horizontally. As in Figure (11-22).

The group of deflection files is equipped in the form of an integrated unit that can be easily disassembled, installed, fixed and adjusted at the inner end of the screen neck so that it covers part of the screen funnel. Thus, it is possible to control the beam radius at an angle as large as possible. We find that the deflection profiles are not of equal thickness and distribution. This was designed to achieve the best distribution of the magnetic field and in the appropriate form for the required beam deflection - Figure (11-24)

The shift of the skew files to the back leads to the reduction of the linear structure of the image (Rast). Likewise, the image is on both sides, since the ray hits the sides of the figure's neck
(11-26). The image may appear in a circle if the regression of the deflection files is large.

As for the deviation of the coils on its axis, it leads to the deviation of the entire image in the same direction, as in Figure (11-25).

Self-induction and ohmic resistance of deflection windings:

Deflection coils 90 ohm resistance self-induction


Horizontal 1.4 mH 1.15 ohms

Verticality 5.65 MilliHenry 3.3 ohms

Deviation Files 110-114

Horizontal 24 mH 42 ohms

Vertical 67 millihenry 28 ohms