SU924912A2 - Device for deflection of cathode-ray tube beam - Google Patents

Description

(54) DEVICE FOR THE DEFLECTION OF THE BEAM OF A BREAD-INSULATED TUBE

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The invention relates to means of scanning images with the help of deflection of an electron beam in a cathode ray tube, and can be used in television, in radar information display devices and in computer information input and output.

According to the main author. St. No. 8433OO is known a device dp of deflection of a beam of a cathode-ray tube containing a differential amplifier, the first and second inputs of which are connected to the emitter, and the first and second outputs are connected to the base of the first and second output transistors, and the collectors of the first and second output transistors are connected via corresponding deflection coils to the emitters of the voltage boost transistors, and through the series-connected auxiliary coils, the voltage switch and the zener diode to the bases of the corresponding voltage transistors and, to; lecturers who are connected to the same constant source, and

emitters through diodes - to another source of constant voltage 11.

A disadvantage of the known device is the increase in the duration of the establishment of the current deviation due to the presence of common-mode currents.

The circuit of the invention is to increase the speed of the device by reducing the time for setting the current deviation.

Claims (1)

In order to achieve the supplied circuit, a second differential amplifier was introduced into the device, the first and second inputs of which are connected to the emitters of the first and second output transistors, two. a comparator and two switches, the outputs of which are connected respectively to the bases of the first and second output transistors, the first inputs of the comparators are connected to the output of the second differential amplifier, and the second to the outputs of the sources, respectively, of the positive and negative cutoff voltage, and the outputs of each comparator are connected to control input of the corresponding key. The drawing shows the electrical circuit of the proposed device. The device contains the first differential amplifier 1, the resistor 2, the first and second output transistors 3 and 4, the transistors 5 and 6 are additive, the deflecting coils 7 and 8, the resistors 9-13, the diodes 14-17, the auxiliary coils 18 and 19, the zener diodes 20 and, 21, sources 22 and 23. constant voltage, second differential amplifier 24, comparators 25 and 26, switches 27 and 28, resistors 29 and 30, positive cut-off source 31, and negative cut-off source 32. The device works as follows. For the case when the voltage corresponding to the maximum current in the right section of the deflection coil 8 is applied to the input of the device, the voltage at the first input of the second differential amplifier 24 is maximal and. causes the appearance of a negative voltage at its output as well as a maximum value. The voltage at the first input of the comparator 26 exceeds the cut-off voltage. The base of the output transistor 3 is connected to a zero potential through a closed switch 28, and the current of the left section of the deflecting coil 7 is zero. At time tg, the input voltage jumps abruptly to zero. A mismatch voltage is applied to the input of amplifier 1, which removes the stages of amplifier 1 from the linear operating mode. However, since the base of the output transistor 3 is shunted by the very low resistance of the switch 28, the maximum unlocking current generated by the force 1 does not fall into the base region of the transistor 3 and, therefore, is not inputted to saturation. Key 28 is opened when the current in the right section of the deflecting roller 8 goes to zero. At the same time, the voltage at the input of the second differential amplifier 24 becomes so small that the voltage at its output is less than the voltage of the cutoff source 32. Thus, the deep saturation mode of the transistor 3 at zero collector current, which is the cause of common-mode current in the OK sections and an increase in the duration of the transient, is eliminated. Similarly, the operation of the amplifier 24, (analog) comparator 25 and the key 27 can be described with the input voltage of the device in the initial state corresponding to the maximum current in the left section of the deflecting roller 7. Thus, the proposed device allows to increase the speed by eliminating the influence nor in-phase currents in the OK sections for the duration of the transient process. The use of the proposed device reduces the time to establish the current deviation by 25% compared with the known device. The invention The device for deflection of a beam of a cathode-ray tube St. No. 843300, distinguished by the fact that, in order to improve speed by reducing the time to establish the current deviation, it introduced a second differential amplifier, the first and second inputs of which are connected respectively to the emitters of the first and second output transistors, two comdators and two switches, outputs which are connected respectively to the bases of the first and second output transistors, with the first inputs of the comparators being connected to the output of the second differential amplifier, and the second to the outputs of the sources corresponding to positive and negative voltages are cut-offs, and the output of each comparator is connected to the control input of the corresponding key. Sources of information taken into account in the examination 1. USSR Author's Certificate No. J 43300, cl. And O4N 3/16, 1979 (prototype).