JP3336789B2 - Flyback transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flyback transformer for applying a high output voltage to an anode of a cathode ray tube of a television receiver or a display device.

[0002]

2. Description of the Related Art FIG. 9 shows a circuit of a conventional general coil laminated type flyback transformer. This type of flyback transformer 1 has a core 2 wound with a primary coil 3 and a secondary coil 4 wound on the outside thereof, and a driving voltage B
₊ Is applied. A collector voltage is applied to the high voltage end of the primary coil 3.

The secondary coil 4 has a plurality of stages of coils 4a to 4e.
And the coils 4a to 4e of each stage are connected in series via the rectifier diode 5, and the output terminal of the coil 4e of the last stage is connected to the anode of the cathode ray tube 6 via the final high-voltage rectifier diode 5f. Have been. The coils 4a to 4e of each stage are laminated and wound around a high-pressure bobbin (not shown) via an insulating material such as an insulating film.

In the middle stage of the secondary coil 4, a drop resistor 7 is provided.
And one end side (drop resistor side) of a resistor circuit in which a variable resistor 8 and a resistor 9 for adjusting a focus voltage are connected in series, and the voltage taken out from the middle stage of the secondary coil 4 is applied by the drop resistor 7. The focus voltage corresponding to the sliding position of the sliding terminal 10 which is stepped down and applied to the variable resistor 8 and slides on the resistor of the variable resistor 8 is taken out from the sliding terminal 10 and is shown in the drawing of the cathode ray tube 6. Is applied to the focus electrode which is not. The other end of the resistor circuit is grounded
Grounded .

[0005] A resistance circuit of a series circuit of the drop resistor 7, the variable resistor 8 and the resistor 9 is accommodated in a focus pack 11. The focus pack 11 accommodates a circuit board 13 in a focus case 12 as shown in FIG.
On one side of the circuit board 13, a resistor circuit as shown in FIG. 9 is formed by printing or the like. Circuit board 13
The resistance circuit forming surface of the knob faces the closing wall surface 14 of the focus case 12, a knob insertion hole 15 is opened in the closing wall 14, and the knob 17 of the operating body 16 is protruded outside through the knob insertion hole 15. I have. A sliding terminal 18 and a center terminal 19 are formed on the bottom side of the operation body 16.

A resistance pattern 20 of a variable resistor as shown in FIG. 8 is formed in an arc shape on the circuit formation surface of the circuit board 13, and a center conductor pattern 21 is formed in the center of the arc shape. By contacting the center terminal 19 of the operation body 16 with the center conductor pattern 21, the sliding terminal 18 is brought into contact with the resistance pattern 20, and the knob 17 of the operation body 16 is rotated.
The sliding terminal 18 slides on the resistance pattern 20, and a voltage corresponding to the sliding position is applied to the focus electrode of the cathode ray tube from the sliding terminal 18 via the center terminal 19.

Normally, an insulating layer (buffer coat) 22 for increasing the withstand voltage of the resistance circuit is formed on the back surface of the circuit board 13 (the surface opposite to the circuit forming surface).

The focus case 12, in which the circuit board 13 is housed, uses a fitting claw 23 in an opening of a case of a flyback transformer (not shown, in which the coils 3, 4 are housed). When the focus case 12 and the flyback transformer case are fitted together, a casting resin such as epoxy is injected into the transformer case, and the focus case 12 and the transformer case are integrally formed by the casting resin. Fixed.

[0009]

Generally, the focus voltage is such that a voltage of 25% ± 2.5% of the high voltage output voltage is taken out.
Assuming that the focus voltage is 25% ± 2.5%, the focus voltage is 6.75 KV ± 0.675 KV. In order to obtain this voltage, as shown in FIG.
In the case of a five-stage configuration of 4e to 4e, a voltage of 10.8 KV is taken out from the middle stage of the second stage from the low voltage end to the resistance circuit of the focus pack 11.

As described above, when the input voltage to the focus pack 11 is taken out from the middle stage of the secondary coil 4,
A voltage of 10.8 KV, which is considerably higher than 6.75 KV ± 0.675 KV required as a focus voltage, is taken in. In this way, since a voltage higher than the actually required focus voltage is taken in, the resistance circuit of the focus pack 11 is taken. In order to increase the insulation withstand voltage of the focus pack, the thickness of the circuit board 13 of the focus pack may be increased, the thickness of the insulating layer 22 may be increased, and the insertion hole 15 of the closing wall 14 of the focus case 12 from the circuit board 13 may be formed. Therefore, it is necessary to provide a complicated means such as taking measures to increase the dielectric strength with respect to the outside of the region up to the area, and the structure of the focus pack 11 becomes complicated and the size thereof increases accordingly.

When taking out the focus voltage,
Since the voltage of 10.8 KV is stepped down through the drop resistor 7 and is introduced into the variable resistor 8, the energy use is lost because the energy of the voltage drop of the drop resistor 7 is wasted as heat. Occurs.

Further, as described above, since various measures are taken to increase the dielectric strength of the focus pack 11, there is a problem that the cost of the focus pack 11 increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. An object of the present invention is to reduce the withstand voltage of a focus pack and prevent unnecessary waste of energy.
Achieving high efficiency of energy utilization, can in a simplified structure of a focus pack in small to provide a flyback transformer and the cost can be reduced.

[0014]

The present invention is configured as follows to achieve the above object. That is, a first invention comprises a primary coil and a secondary coil wound around a core, and a voltage is adjusted by a variable resistor from a secondary side to take out a focus voltage, and a resistance circuit of the variable resistor is provided. Is variable to the low pressure end side of the secondary coil in the flyback transformer housed in the focus pack
One end of the resistor is connected, and two ends of this variable resistor
A series circuit consisting of three capacitors is connected in parallel,
Connection between the high voltage end of the primary coil and the two capacitors
A first die having a cathode connected to the connection between
An electrode is connected, and the connection and the output of the secondary coil
The secondary coil is connected to the cathode side
2 diodes are connected, and the primary coil and the secondary coil are connected.
Yl to apply a voltage of the voltage adjustment range min to the variable resistor
That power coil and to are shared with, of the variable resistor
The output side is configured as characterized in that the pressure coil are connected in the output is in full Okasu voltage wound on the secondary side with respect to previous SL core.

According to a second aspect of the present invention, there is provided a primary coil and a secondary coil wound around a core, and a voltage is adjusted from a secondary side by a variable resistor to take out a focus voltage. of the flyback transformer resistor circuit contained in the focus pack, said variable resistor one end of which is connected to the low pressure end of the secondary coil, the voltage adjustment range fraction in the secondary coil is a variable resistor voltage are also used as a power supply coil for applying a said output side of the variable resistor with the pressure coil is connected in the output wound on the secondary side full O <br/> carcass voltage to the core The feature is that it is.

Further, a third invention comprises a primary coil and a secondary coil wound around a core, and a voltage is adjusted from a secondary side by a variable resistor to take out a focus voltage. fly in back transformer, the core of the resistor circuit is accommodated in the focus pack
The medium-pressure coil is wound on the secondary side of the
Between the low-voltage end of the variable resistor and one end of the variable resistor.
A third diode connected on the cathode side to the
The output of the variable resistor is connected to the low voltage end of the medium voltage coil.
And two ends of the variable resistor
A series circuit composed of capacitors is connected in parallel, and a high-voltage end of the primary coil is connected to a connection portion of the two capacitors.
A first diode between which the cathode side is connected to the connection portion
Are connected, and the connection portion and the output end of the medium-voltage coil
A second coil whose cathode side is connected to the medium-pressure coil during
The primary coil and the medium pressure coil are connected
Le, to apply a voltage of the voltage adjustment range min to the variable resistor
To function as a power supply coil that, it is also used to function as a co-yl which outputs a full O <br/> carcass voltage in said pressure coil
It is configured as characterized by the.

Further, a fourth invention comprises a primary coil and a secondary coil wound around a core, and a voltage is adjusted from a secondary side by a variable resistor to take out a focus voltage. In a flyback transformer housed in a focus pack, a medium-voltage coil is wound on the secondary side with respect to the core , and a cathode side is connected to the variable resistor at one end of the medium- voltage coil. one end of the variable resistor is connected via a da <br/> diode, before
Serial output side of the variable resistor is connected to the low pressure end of the medium pressure coil, and the function of this intermediate pressure coil, as a power supply coil for applying a voltage of the voltage adjustment range component to said variable resistor,
Is configured as characterized in that is also used and a function as a coil for outputting a full Okasu voltage.

Further, the fifth invention has the configuration of the third invention, wherein a second medium-pressure coil is wound on the secondary side of the core.
Takes out the second focus voltage in parallel with the variable resistor
A second variable resistor is connected, and the second variable resistor
The output side is connected to the low voltage end side of the second medium voltage coil.
The feature is that it is.

[0019]

In the present invention having the above-described structure, a voltage corresponding to the voltage adjustment range of the variable resistor is generated by the power supply coil or the power supply and applied to the variable resistor. The variable resistor adjusts the voltage within the range of the voltage, and the adjusted voltage is boosted by the medium-voltage coil to output a focus voltage.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. In the following description of the respective embodiments, the same reference numerals are given to the same names in the respective embodiments and in the conventional example, and the overlapping description will be omitted. FIG. 1 shows a first embodiment of the present invention. In this embodiment, the primary coil 3
The power supply coil 24 is wound around the high-voltage end of the
One end of the variable resistor 8 is connected to the winding end of 24 via a rectifier diode 25, and the other end of the variable resistor 8 is connected to ground. A smoothing capacitor 26 is connected in parallel with the variable resistor 8.

In the present embodiment, DC 2.5 V is set as the voltage for the voltage adjustment range of the variable resistor 8, and the power supply coil 24 generates a collector pulse of a DC component (DC component) of 2.5 V.
It is formed by winding up the number of turns that generates a voltage of V. The voltage generated by the power supply coil 24 is a rectifier diode.
The DC component is converted into a DC component by the 25 and the smoothing capacitor 26, and a DC voltage of 2.5 KV is applied to the variable resistor 8.

The sliding terminal 18 of the variable resistor 8 has a medium-voltage coil.
27 is connected. This medium-voltage coil 27 is wound around the secondary side of the core 2, boosts the voltage adjusted by the sliding movement of the sliding terminal 18, and outputs a focus voltage from its output end. In the example, the number of turns is set so that the DC voltage of the sliding terminal 18 is boosted by DC 4.925 KV. A diode 28 is connected to the output end of the medium voltage coil 27, and the output voltage of the medium voltage coil is
Through the switch, a DC focus voltage is applied to the focus electrode of the cathode ray tube.

The resistance circuit of the variable resistor 8 is formed on a circuit board 13 by printing or the like as in the conventional example, and is accommodated in the focus case 12.

According to this embodiment, since the voltage within the voltage adjustment range generated by the power supply coil 24 is applied to the variable resistor 8, the dielectric strength of the focus pack 11 is The applied voltage is as low as 2.5 KV, which is equivalent to the applied voltage of 10.8 KV, which is sufficiently lower than 10.8 KV of the conventional example. Therefore, the circuit board 13 for forming the resistance circuit can be made thinner. it becomes possible to omit the buffer coat 22, moreover, by the like can be omitted complicated means for increasing the external dielectric strength in the region of the knob insertion hole 15 of the circuit board 13 and the focus casing 12, sufficient focus pack size Therefore, the cost of the focus pack can be significantly reduced.

Further, a low generated voltage of the power supply coil 24 is applied to the variable resistor 8 as it is.
Since the resistance circuit of the focus pack 11 is not connected to the middle stage of the secondary coil 4 having a high voltage unlike the conventional example,
The drop resistor 7 of the conventional example becomes unnecessary, and accordingly, the waste of the energy dissipated as heat energy by the drop resistor 7 can be prevented, and the efficiency of energy utilization can be increased, which is economically advantageous. is there.

As described above, since the drop resistor can be omitted and the voltage applied to the variable resistor is reduced, the variable resistor itself is also reduced in size, and the resistance pattern formed on the circuit board 13 has a low withstand voltage. Becoming, for example, a center terminal
Since the distance between the resistor 19 and the resistor pattern 20 can be reduced from the conventional one shown in FIG. 8A to the one shown in FIG. 8B, the circuit board 13 can be downsized. In addition to the simplification of the withstand voltage means between the focus pack 12 and the focus case 12, the focus pack 11 can be further reduced in size and cost.

FIG. 2 shows a second embodiment of the present invention. This embodiment is characterized in that the secondary coil 4 also has a function as a power supply coil for applying a voltage within the voltage adjustment range to the variable resistor 8. Is the same as In the figure, one end of a variable resistor 8 is connected to the low voltage end of the secondary coil 4, and the other end of the variable resistor 8 is grounded to the ground. min DC voltage is adapted to be generated is applied by spur Namerasaku capacitor 26. Then, the voltage of the sliding terminal 18 of the variable resistor 8 is boosted to the focus voltage by the medium-voltage coil 27 wound on the secondary side of the core 2 and output.

In this embodiment, the same effects as those of the first embodiment are obtained, and the parallel circuit of the capacitor 26 and the variable resistor 8 functions as a snubber circuit, and removes an oscillating component to generate ringing ( The effect of suppressing the occurrence of stripes on the screen of the cathode ray tube is obtained.

FIGS. 3 and 4 show various embodiments in which the primary coil 3 of the flyback transformer functions as a power supply coil of the variable resistor 8. FIG. FIG. 3A shows a configuration in which both the primary coil 3 and the secondary coil 4 function as a power supply coil for generating a voltage within the voltage adjustment range of the variable resistor 8. One end of the variable resistor 8 is connected to one end, the other end of the variable resistor 8 is connected to ground, and capacitors 26a and 26 are connected in parallel with the variable resistor.
b series circuit is connected. Then, the high voltage end side of the primary coil 3 is connected to the connection portion A of the smoothing capacitors 26a and 26b via a diode 29.
a, 26b and the first coil 4 of the secondary coil 4
The output terminal (a) is connected via a diode 30 to the output terminal (end terminal of winding).

The sliding terminal 18 of the variable resistor 8 is connected to an intermediate voltage coil 27 wound around the secondary side of the core 2, and a focus voltage is applied from an output terminal of the intermediate voltage coil 27 via a diode 28. It is output. Also in this embodiment, a snubber circuit is formed by the capacitors 26a and 26b and the variable resistor 8, and a vibration component is removed to prevent ringing on the screen of the cathode ray tube. This embodiment also has the same effects as the above embodiments.

FIG. 3B shows the primary coil 3.
Only the function as a power supply coil for generating a voltage within the voltage adjustment range of the variable resistor 8 is achieved. Therefore, the secondary coil 4 side and the medium voltage coil 27 side are completely separated from each other, and an opposite diode is provided between one end of the variable resistor 8 and the low voltage end (winding start end) of the medium voltage coil 27. 31 is interposed,
A forward diode 32 is connected between the connection point A of the smoothing capacitors 26a and 26b and the output terminal of the intermediate voltage coil 27.

The embodiment shown in FIG. 3B has the same effects as the above embodiments.

The circuit shown in FIG. 3 (c) is obtained by forming a variable resistor 33 for taking out a screen voltage in the focus pack 11, and otherwise is the same as the circuit of FIG. 3 (b). The same effects as those of the above-described embodiments can be obtained.

FIG. 4 (a) is similar to FIG. 3 (c) except that a variable resistor 33 for taking out a screen voltage is provided in the focus pack 11. In the circuit of FIG. 4A, one end of a variable resistor 33 is connected to smoothing capacitors 26a and 26b.
Of the variable resistor 33 is connected to the output terminal of the intermediate voltage coil 27 via the diode 32 to extract the screen voltage more than that shown in FIG. Of the variable resistor 33 is reduced. FIG. 4A also has the same effects as those of the above embodiments.

FIG. 4B shows a variable resistor 33 for taking out the screen voltage and a variable resistor for taking out the double focus voltage in the focus pack 11 in addition to the variable resistor 8 for taking out the focus voltage. Are connected in parallel, and the voltage taken out at the sliding terminal of the variable resistor 34 is boosted by another medium-voltage coil 35 and output via a diode 36. The voltage taken out by the variable resistor 8 is boosted by the medium voltage coil 27 and output to the vertical focus electrode of the cathode ray tube, and the voltage taken out by the variable resistor 34 is boosted by another medium voltage coil 35, It is added to the horizontal focus electrode of the cathode ray tube. A dynamic capacitor 37 connected to the cathode side of the diode 36 is for inputting a parabolic waveform voltage.

The variable resistor 8, 33, and 34 shown in FIG. 4B are also configured to apply a voltage within the voltage adjustment range, so that the focus pack 11 can be downsized. The same effects as those of the above-described embodiments can be obtained.

FIG. 5 shows an embodiment in which the medium-voltage coil 27 for boosting functions as a power supply coil for applying a voltage within the voltage adjustment range to the variable resistor 8. (A) of FIG.
Is connected to the low-voltage end of the medium-voltage coil 27 and one end of the variable resistor 8 with a diode 38 having an opposite direction. The variable resistor 8 has a smoothing capacitor for converting the voltage applied to the variable resistor 8 to DC.
26 are connected in parallel. The output end of the intermediate voltage coil 27 is connected to the cathode side of the diode 39, and the anode side of the diode 39 is grounded. Also in the circuit shown in FIG. 5A, the medium-voltage coil 27 functions as a power supply coil, and the voltage generated by the medium-voltage coil 27 is converted to direct current by the smoothing capacitor 26 and is supplied to the variable resistor 8 by the voltage adjustment range. The voltage is applied as a voltage, and the voltage taken out from the sliding terminal 18 of the variable resistor 8 is boosted by the medium voltage coil 27, further rectified by the diode 28, and output as a DC focus voltage. The circuit shown in FIG. 5A also has the same effects as the above embodiments.

FIG. 5B shows a variable resistor 8.
One end of the medium voltage coil 27
, The sliding terminal 18 of the variable resistor 8 is connected to the low voltage end of the medium voltage coil 27, and a diode 41 is connected between the low voltage terminal of the medium voltage coil 27 and the ground. In this circuit as well, the medium voltage coil 27 functions as a power supply coil for applying a voltage within the voltage adjustment range to the variable resistor 8, and the voltage taken out from the sliding terminal 18 of the variable resistor 8 is boosted by the medium voltage coil 27. Then, it is output as a direct-current focus voltage via the diode 28, and has the same effects as those of the above embodiments.

FIG. 6 shows still another embodiment. In this embodiment, a power source 42 for applying a voltage within a voltage adjustment range is connected in parallel to the variable resistor 8 and the variable resistor 8 slides. Terminal
The voltage taken out at 18 is boosted by the medium-voltage coil 27, and is output as a DC focus voltage by the capacitor 43 and the diode 28. The circuit of this embodiment also has the same effects as the above embodiments.

It should be noted that the present invention is not limited to the above embodiments, but can adopt various embodiments.

[0041]

According to the present invention, a voltage corresponding to a voltage adjustment range is applied to a variable resistor for extracting a focus voltage using a power supply coil or a power supply, and a voltage extracted from a sliding terminal of the variable resistor is applied to an intermediate voltage. Since the voltage is boosted by the coil and the focus voltage is output, the voltage applied to the variable resistor for extracting the focus voltage is sufficiently low, and therefore the withstand voltage of the variable resistor is sufficiently low. The circuit board of the focus pack for forming the resistor can be downsized, and the buffer coat of the insulating layer formed on the circuit board for increasing the withstand voltage of the focus pack can be omitted in some cases. The means for withstanding voltage can be simplified, and the variable resistor itself can be reduced in size as much as the withstand voltage of the variable resistor decreases, The pattern spacing on the road can be narrowed, and the drop resistor required in the conventional focus pack resistance circuit can be omitted.As a result, the focus pack can be much smaller than the conventional focus pack. Accordingly, the cost of the focus pack can be significantly reduced.

As described above, since the drop resistor required in the conventional focus pack resistor circuit can be omitted, there is no waste of energy consumed and radiated by the drop resistor, and a high efficiency of energy use. It is very economically advantageous.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a second embodiment of the present invention.

FIG. 3 is various circuit diagrams of an embodiment in which a primary coil of a flyback transformer functions as a power supply coil of a variable resistor for extracting a focus voltage.

FIG. 4 is an explanatory diagram of another circuit example in which a primary coil of a flyback transformer functions as a power supply coil.

FIG. 5 is various circuit diagrams of an embodiment in which a medium-voltage coil wound on a secondary side of a core functions as a power supply coil of a variable resistor for adjusting a focus voltage.

FIG. 6 is a circuit diagram of another embodiment of the present invention.

FIG. 7 is a structural explanatory view showing an example of a focus pack of a flyback transformer.

FIG. 8 is an explanatory diagram of a resistance pattern formed on the circuit board 13 of FIG. 7;

FIG. 9 is a circuit diagram of a conventional flyback transformer.

[Explanation of symbols]

 1 Flyback transformer 3 Primary coil 4 Secondary coil 8 Variable resistor 11 Focus pack 27 Medium pressure coil

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 38/42 H01C 13/00

Claims (5)

(57) [Claims] A primary coil and a secondary coil wound around a core, wherein a voltage is adjusted from a secondary side by a variable resistor to extract a focus voltage, and a resistance circuit of the variable resistor includes a focus pack. in a flyback transformer which is accommodated in, allowed the low pressure end of the secondary coil
One end of the variable resistor is connected, and both ends of this variable resistor
A series circuit consisting of two capacitors is connected in parallel,
The connection between the high voltage end of the primary coil and the two capacitors
A first portion having a cathode connected to the connection portion between the first portion and the connection portion;
A diode is connected, and the connection portion and the secondary coil
The cathode side was connected to the secondary coil between the output end
A second diode is connected to connect the primary coil and the secondary
The coil applies a voltage within the voltage adjustment range to the variable resistor
And power coil that it are shared, the variable resistor
Flyback transformer on the output side, wherein a pressure coil are connected in the output is in full Oka <br/> scan voltage wound on the secondary side with respect to previous SL core. 2. A power supply comprising a primary coil and a secondary coil wound around a core, wherein a voltage is adjusted from a secondary side by a variable resistor to extract a focus voltage, and a resistance circuit of the variable resistor is a focus pack. in the flyback transformer is accommodated in the front to the low pressure end of the secondary coil
Serial variable resistor one end is connected to are also used as a power supply coil for applying a voltage of the voltage adjustment range fraction in the secondary coil is a variable resistor, to the core on the output side of the variable resistor a flyback transformer, wherein the <br/> medium pressure coil for outputting is in full Okasu voltage wound on the secondary side is connected. 3. A variable resistor comprising a primary coil and a secondary coil wound around a core, wherein a voltage is adjusted by a variable resistor from a secondary side, and a focus voltage is taken out. Chu圧Ko flyback transformer housed in the secondary side with respect to the core
And the variable-voltage end of the medium-voltage coil and the variable resistance
The cathode side is connected to the variable resistor between one end of the resistor and
The third diode connected is connected to the
An output side is connected to a low voltage end side of the medium voltage coil,
A series consisting of two capacitors at both ends of the variable resistor
Circuits are connected in parallel, the high voltage end side of the primary coil and the front
Serial cathode to the connecting portion between the connecting section of the two capacitors
A first diode connected to the diode side is connected,
Between the connection part and the output end of the medium-pressure coil,
A second diode connected to the cathode side is connected
Te, the medium pressure coil and the primary coil, and a power supply coil for applying a voltage of the voltage adjustment range min to the variable resistor
To function, it is the medium pressure coil to output the full Okasu voltage
Flyback transformer also functions as Turkey yl characterized in that is also used. 4. A variable resistor comprising a primary coil and a secondary coil wound around a core, wherein a voltage is adjusted from a secondary side by a variable resistor to extract a focus voltage, and a resistance circuit of the variable resistor is a focus pack. In the flyback transformer housed in the transformer, a medium-voltage coil is wound on the secondary side of the core, and the variable resistor is wound on one end of the medium-pressure coil.
One end of the friendly <br/> variable resistor is connected via a diode having a cathode side connected to the anti-vessel, the output side of the variable resistor is connected to the low pressure end of the medium pressure coil, in this the pressure coil, and functions as a power supply coil for applying the variable resistor to the voltage adjustment range fraction of the voltage, outputs a full Okasu voltage
A flyback transformer which serves as a coil and characterized in that is also used to. 5. A second medium-pressure coil on the secondary side with respect to the core.
Wound and a second focus voltage in parallel with the variable resistor
A second variable resistor to be taken out is connected, and the second variable resistor is connected to the second variable resistor.
The output side of the arrester is connected to the low voltage end of the second medium voltage coil
3. flyback transformer, wherein the being.