DE2823963A1 - Line deflection circuit with reduced deflection distortion - has resistor and capacitor in parallel with inductance - Google Patents

Abstract

Distortions in the CRT line deflection are due to brief white loads. The circuit has a tangential capacitor in series with the deflection coils. It is in parallel with a series circuit of a capacitor and a diode, damped by a resistor. A circuit with an inductance (9, 12) determining the linearity or the amplitude, and connected in series with the deflection coils (6), has a series circuit consisting of the capacitor (20) and resistor (23) in parallel with the inductance (9, 12). The middle point of the circuit (20, 23) is connected through a diode (19) to a point +UB) whose potential corresponds to the diode (19) forward direction.

Description

Line deflection circuit with reduced deflection interference for short

early exposure to white, addition to P 27 47 340 The main application concerns a line deflection circuit with reduced deflection interference with short-term white exposure with a tangent capacitor lying in series with the deflection coils and one of the Flyback transformer fed high voltage rectifier.

The invention according to the main application is based on the object To reduce distraction disturbances in the case of a white load in the picture.

This object is achieved in that parallel to the tangent capacitor the series connection of a capacitor and a diode polarized so that this due to the change in amplitude of the Line-frequency parabolic voltage on the tangent capacitor conductive is controlled.

In the circuit described, it is known, in series with the deflection coils, in particular between the deflection coils and the tangent capacitor, even more adjustable ones Switch on inductors. These are used, for example, to adjust the linearity of the Line deflection and the line deflection amplitude. Such additional inductances easily lead to partial oscillations, which are visible on the screen as disturbances will. It is therefore known in parallel to the adjustable inductances still to switch an RC element serving for damping. By such an RC element but the geometry of the deflection is influenced to a small extent.

If this well-known RC element to suppress the partial oscillations and the circuit according to the parent application for the elimination of distraction disturbances short-term white exposure are applied at the same time, a total of about five components, namely two resistors, two capacitors and a diode are required. This means a relatively large amount of circuit technology.

Although it is possible instead of the circuit according to the main application a resistor between the operating voltage terminal and the tangent capacitor to turn on. Such a resistance is also able to reduce the distraction disturbances to be adequately removed in the event of short-term exposure to white. With such a circuit the cost of components is lower.

However, the resistance mentioned causes a far greater geometrical error than the mentioned RC element in parallel with the adjustable inductance. The geometry error consists in particular in an expansion of the deflection at the left edge of the image.

The object of the invention is to utilize the circuit to create a circuit according to the main application that requires few components both the partial oscillations are suppressed as well as distraction disturbances in the case of short-term Avoids white exposure and still does not cause any disruptive geometrical errors.

This object is achieved by the invention described in claim 1 solved.

The invention is based on the knowledge that the circuit after the main application and the RC element parallel to the adjustable inductance in clever way to a simplified one Let circuit unite, the two tasks, namely suppression of partial vibrations and elimination the distraction disorder with short-term exposure to white, equally resolves. The number of required components is reduced from five to three. The resistance described between the operating voltage terminal and the tangent capacitor, the considerable Causes geometric errors, is no longer required in the circuit according to the invention.

The invention is based on the drawing of an exemplary embodiment explained.

The figure shows that controlled by the line-frequency switching voltage 1 Line output transistor 2, the working winding 3 and the high-voltage winding 4 of the flyback transformer 5, the line deflection coils 6, which are used to set the Current distribution in the deflection coils 6 serving differential coil 7, the tangent capacitor 8, the high-voltage cascade 10 and the picture tube 11.

Between the deflection coils 6 and the tangent capacitor 8 are still the linearity coil 9 and the coil 12 used to adjust the image width. The inductances of the coils 9, 12 can lead to partial oscillations and thus to disturbances in the reproduced image. To avoid such vibrations, the dashed line would have to be Drawn RC element 13,14 are switched on. To reduce distraction in the case of short-term exposure to white, the dashed line would also have to be in accordance with the main application Parts 19 ', 20' and 23 'drawn in parallel to the tangent capacitor 8 are switched on will.

Instead of the five described components 13, 14, 19 ', 20', 23 'are now the diode 19, the capacitor 20 and the resistor 23 in the manner shown switched on. These components in the arrangement shown are surprising Way, both tasks of the five components shown in dashed lines. The condenser 20 and the diode 19 act as in the parent application to reduce the deflection interference with white exposure. The effect of these components is the same as in the main application practically parallel to the tangent capacitor 8 because both the lower end of the tangent capacitor 8 as well as the anode of the diode 19 in terms of AC voltage to earth, i.e. on a cold point. The capacitor 20 and the resistor 23 fulfill the function of the RC element 13, 14 which is necessary per se. The two resistors shown in dashed lines, two capacitors and a diode are thus replaced by the three components 19, 20, 23.

The dashed line resistor 15, which is described in the above This is also a way of reducing distraction during short-term exposure to white could serve, but undesirably causes considerable geometry errors, is not needed.

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Claims (2)

Claims! 1,} line deflection circuit with it reduces deflection interference in the case of brief exposure to whitening with one lying in series with the deflection coils Tangent capacitor, a series circuit of which is damped by a resistor Capacitor and a diode is connected in parallel, according to patent application P 27 47 340, characterized in that in a circuit in which in series with the Deflection coils (6) nor an inductance which determines the linearity or the amplitude (9,12), the series connection of the capacitor (20) and the resistor (23) parallel to the inductance (9,12) and the center point of the series connection (20,23) is connected via the diode (in) 'to a circuit point (+ UB) whose DC voltage roughly equal to that of the center point or something in the forward direction the diode (19) is polarized. 2. Circuit according to claim 1, characterized in that the diode (19) lies between the midpoint and the operating voltage terminal (+ mg).