JPH03120582A - Horizontal linearity switching circuit for crt display monitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a horizontal linearity switching circuit for a CRT display monitor.

[Conventional technology]

FIG. 2 shows a conventional horizontal linearity switching circuit. In this figure, 1 is a horizontal switching transistor, 2 is a damper diode, 3 is a retrace capacitor, 4 is a horizontal deflection yoke, 5 is a flyback transformer that creates high voltage, 6 is a linearity coil, 7 is a figure-8 correction capacitor,
9.10 is a switching circuit for switching the linearity coil 6 and the figure-8 correction capacitor 7.

Next, the operation will be explained.

By applying a horizontal periodic pulse to the base of the horizontal switching transistor 1 and switching it, a sawtooth wave current synchronized with the horizontal frequency is generated in the horizontal deflection yoke 4 through a resonant circuit of the damper diode 2, the retrace capacitor 3, and the horizontal deflection yoke 4. flow. At this time, the current flowing through the damper diode 2 is greater than the current flowing through the horizontal switching transistor 1, so the left side of the screen becomes elongated. To correct this, damper diode 2
The nearness coil 6 is placed in series with the horizontal deflection yoke 4 so that the inductance becomes large only when current flows through the horizontal deflection yoke 4.

In addition, a figure-8 correction capacitor 7 is inserted to correct the elongation at both ends of the screen due to the spherical aberration of the CRT.

The values of the linearity coil 6 and the S-shaped correction capacitor 7 vary depending on the horizontal frequency. That is, when the horizontal frequency is high, the value of the linearity coil 6 is small;
The value of the figure-8 correction capacitor 7 is also small. Conversely, when the horizontal frequency is low, the value of the linearity coil 6 is large and the value of the figure-8 correction capacitor 7 is also large.

Therefore, in a display monitor that does not have one horizontal frequency, when the horizontal frequency changes, the values of the linearity coil 6 and the figure-8 correction capacitor 7 are each switched by a switching cycle of $9.10. That is, when the horizontal frequency is high, the switching circuit 9 of the linearity coil 6 is ON, and the switching circuit 10 of the figure-8 correction capacitor 7 is OFF.
When the horizontal frequency is low, the switching circuit FIII9 of the linearity coil 6 is OFF, and the switching circuit 10 of the figure-8 correction capacitor 7 is ON.

[Problem to be solved by the invention]

Since the conventional switching circuit is configured as described above, 1
Two switching circuits 9 and 10, including a linearity coil 6 and a figure-8 correction capacitor 7, are required to switch between two horizontal frequencies.

This invention was made to solve the above-mentioned problems, and aims to combine two conventional switching circuits into one.

[Means to solve the problem]

The horizontal linearity switching circuit for a CRT display monitor according to the present invention combines two switching circuits into one using a C contact relay.

[Effect]

The switching circuit according to the present invention can perform 0N10FF of two conventional circuits at the same time using a C contact relay.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a horizontal switching transistor;
2 is a damper diode, 3 is a trace capacitor,
4 is a horizontal deflection yoke, 5 is a flyback transformer that generates high voltage, 6 is a linearity coil, 7 is a figure-8 correction capacitor, and 8 is a C contact relay for switching the linearity coil 6 and figure-8 correction capacitor 7 at the same time.

In the C contact relay coil 8, when the horizontal frequency is high, the linearity coil 6 side is turned on and the figure-8 correction capacitor 7 side is turned off. Conversely, when the horizontal frequency is low, the linearity coil 6 side is 0FFt, and the figure-8 correction capacitor 7 side is OFF. This makes it possible to obtain constant horizontal linearity even when the horizontal frequency changes.

Although the above embodiment uses the C-contact relay 8 in the switching circuit, other transfer type switching means may be used and the same effects as in the above embodiment can be achieved.

〔Effect of the invention〕

As explained above, the present invention is provided with a switching means that simultaneously switches the linearity coil and the figure-8 correction capacitor, so the two conventional switching circuits are combined into one, making the circuit cheaper and reducing the parts required. It also has the effect of reducing points.

[Brief explanation of drawings]

FIG. 1 is a horizontal linear diagram according to an embodiment of the present invention, in which 1 is a horizontal switching transistor, 2 is a damper diode, 3 is a retrace capacitor, 4 is a horizontal deflection yoke, 5 is a flyback transformer, 6 is a linearity coil, and 7 is a horizontal linear diagram according to an embodiment of the present invention. is a figure 8 correction capacitor, and 8 is a C contact relay. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A horizontal linearity switching circuit for a CRT display monitor of automatic frequency tracking and switching type, characterized in that the CRT display monitor is equipped with switching means for simultaneously switching a linearity coil and an S-shaped correction capacitor for keeping horizontal linearity constant.