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Showing papers on "Flyback transformer published in 1970"


Proceedings ArticleDOI
20 Apr 1970
TL;DR: In this paper, a high power rotary transformer (1 k W ) was considered as a replacement for slip-rings in a future satellite, and a design procedure was described which provided the engineer with a rough estimate of size and weight of a near optimum transformer given the power level, frequency of operation, and material used.
Abstract: A high power rotary transformer (1 k W ) was considered as a replacement for slip-rings in a future satellite. A study was done to determine the best electrical design taking into account mechanical limitations while maximizing efficiency. Ferrite was used in a configuration which can be ground by any good machine shop. A design procedure is described which provides the engineer with a rough estimate of size and weight of a near optimum transformer given the power level, frequency of operation, and material to be used. The electrical circuit used should be considered during the transformer design. In the widely used voltage controlled push-pull square wave converter there is the problem of transistor storage and fall time. Usually one transistor is turned on before the other is off. The latter transistor then traverses through a high power dissipation region, the peak power being twice the input voltage times input current. Transistors picked for low saturation voltage are usually slower devices aggravating the turn-off dissipation problem. An operating procedure which minimizes these turn-off losses and prevents excursion through high instantaneous dissipation regions has been devised. It allowed the construction of a 1000 watt converter (dc-dc rotary transformer) which runs at a 92% efficiency (including rectifier losses) with just a total of 10 watts of transistor dissipation. Operating levels are 24 volts, 50 amps in and out.

35 citations


Patent
28 Dec 1970
TL;DR: In this paper, a solid-state high-voltage regulation circuit for devices such as television receivers which incorporate a flyback transformer is presented, where voltage changes across the transformer secondary winding are compared to a stable reference and any difference is amplified and applied to control the flow of current to the transformer primary coil.
Abstract: A solid-state high-voltage regulation circuit for devices such as television receivers which incorporate a flyback transformer. Voltage changes across the transformer secondary winding are compared to a stable reference, and any difference is amplified and applied to control the flow of current to the transformer primary coil. The output voltage is thus maintained essentially constant.

27 citations


Patent
08 Jul 1970
TL;DR: A support structure for a piezoelectric transformer of the kind operable in accordance with the lambda-mode is described in this article. But it is not shown in this paper.
Abstract: A support structure for a piezoelectric transformer of the kind operable in accordance with the lambda -mode, which supports the piezoelectric transformer at the node of minimum displacement of the drive section of the transformer and is an electrical conductor so that it serves also as a lead wire. An assembly including the piezoelectric transformer, the support structure and a rectifier element is housed in a casing or enclosed in an envelope made vacuous or filled with an insulating gas so that it is usable as a high-voltage generator for television receivers.

12 citations


Patent
25 Sep 1970
TL;DR: In this paper, a high voltage generating apparatus comprising a piezoelectric transformer element for generating high AC voltage and a voltage step-up rectifier connected to the output electrode for generating a high DC voltage is provided.
Abstract: In a high voltage generating apparatus comprising a piezoelectric transformer element for generating a high AC voltage and a voltage step-up rectifier connected to the output electrode for generating a high DC voltage, there is provided a casing divided into two compartments by means of a partition wall for containing the piezoelectric transformer element and the rectifier respectively. Sealing means is provided between the periphery of the partition wall and the inner surface of the casing to electrically isolate the piezoelectric transformer element from the voltage step-up rectifier.

11 citations


Patent
Lawrence C. Marsh1
30 Nov 1970
TL;DR: In this article, a solenoid control apparatus includes an auxiliary drive circuit comprising a boosting network and a flyback network connected in series with solenoids and a power supply.
Abstract: A solenoid control apparatus includes a control switch connected in series with a solenoid and a power supply The control switch energizes the solenoid with an energizing current when the switch is rendered conductive and deenergizes the solenoid which develops a flyback voltage when the switch is rendered nonconductive Further, the solenoid control apparatus includes an auxiliary drive circuit comprising a boosting network connected in series with the solenoid and a flyback network connected in parallel with the solenoid The flyback network includes a Zener diode for limiting the flyback voltage to a maximum level The maximum level is sufficiently high to rapidly decrease the energizing current through the solenoid as the control switch is rendered nonconductive thereby to minimize the pull-in time of the solenoid However, the maximum level is sufficiently low to protect the control switch from damage due to the flyback voltage The boosting network includes the parallel combination of a storage leg, a bypass leg and a reset leg The storage leg includes a storage capacitor connected to discharge through the solenoid to temporarily increase the energizing current through the solenoid as the control switch is rendered conductive thereby to minimize the pull-in time of the solenoid The bypass leg includes a bypass diode connected to shunt energizing current around the storage capacitor to maintain the solenoid energized after the capacitor has discharged through the solenoid The reset leg includes a reset inductor connected to combine with the storage capacitor to form a parallel resonant circuit which oscillates for a half-cycle to charge the capacitor

11 citations


Patent
31 Aug 1970
TL;DR: In this article, the output of a voltage-controlled local oscillator is mixed with the stored IF signal to produce a replica of the input signal to provide an IF signal which is simultaneously passed to a frequency discriminator and a circulating memory.
Abstract: A received RF signal is mixed with the output of a voltage-controlled local oscillator to provide an IF signal which is simultaneously passed to a frequency discriminator and a circulating memory. Control voltage for the oscillator is provided by an AFC unit which comprises an integrator receiving selected constant voltage inputs. During the search mode a search ramp is generated by the integrator. A flyback circuit causes the search voltage to repeat its traverse over a prescribed range. Bipolar video discriminator outputs above a predetermined threshold place the system in the lock mode and selectively gate two settable, constant voltage inputs to furnish a triangle wave integrator output centered on a voltage corresponding to the desired local oscillator frequency. The oscillator output is mixed with the stored IF to produce a replica of the input signal.

10 citations


Patent
Tokio Isogal1, Eiichi Isikawa1, Hisashi Yuza1, Takasi Tahara1, Takao Miyashita1, Norio Ikemoto1 
02 Nov 1970
TL;DR: In this paper, the authors proposed an improved structure of a pulse transformer for simultaneously firing all the gates of a multiplicity of series-connected or series-and parallel-connected thyristors, having a greater insulation strength and a good resistivity to external shocks.
Abstract: An improved structure of a pulse transformer for simultaneously firing all the gates of a multiplicity of series-connected or series- and parallel-connected thyristors as is the case with a converter in dc transmission equipment, having a greater insulation strength and a good resistivity to external shocks. Specifically, since the converter used at high tension renders the line voltage of each thyristor higher, a molded insulating cylinder is disposed between a primary conductor and secondary conductor units of the transformer, whereby potential distributions between the secondary transformer units and the insulating cylinder and between the secondary transformer units adjacent to one another can be improved by providing conductive layers embedded in the insulating cylinder, and the pulse transformer can be made of a dry tape and small in size.

8 citations


Patent
28 Sep 1970
TL;DR: In this article, a video signal level clamping arrangement for a television camera is presented, in which input video signals are clamped to a fixed potential once during each line flyback.
Abstract: A video signal level clamping arrangement for a television camera in which input video signals are clamped to a fixed potential once during each line flyback. The clamped video signals are fed to a signal path into which signals are gated, each of the signals extending for at least the duration of one line flyback period. The resultant spurious free waveform is clamped to a further fixed potential source which is controlled such that it does not clamp during line flyback or outside field suppression. The waveform resulting from the last mentioned clamping is amplitude clipped to produce a stabilized D.C. level corresponding to a predetermined shade, e.g., black.

6 citations


Patent
Antonius Boekhorst1
10 Mar 1970
TL;DR: In this article, a circuit arrangement for adjusting the linearity of the deflection signal generated for a deflection system, particularly for a field-deflection signal in a television receiver, is presented.
Abstract: A circuit arrangement for adjusting the linearity of the deflection signal generated for a deflection system, particularly for a field deflection signal in a television receiver. Two RCnetworks which are connected through a third RC-network during the sweep are arranged after the field oscillator between supply voltage and earth. The variation of the resistor in this third RC-network renders it possible to vary the curvature of the voltage waveform at the output. During the flyback the two charge capacitors are discharged by means of a diode which is connected parallel to the third network. The frequency amplitude and linearity adjusting members are separated from one another.

5 citations


Patent
13 Jul 1970
TL;DR: In this paper, a DC voltage is impressed upon the driving electrode to vary the resonance frequency to regulate the output voltage characteristics in a piezoelectric transformer circuit, where a high voltage is produced at the output electrode of the PZE transformer by applying a driving voltage of a frequency equal or close to the Resonance Frequency (RF) across the driving electrodes thereof.
Abstract: In a piezoelectric transformer circuit wherein a high voltage is produced at the output electrode of the piezoelectric transformer by applying a driving voltage of a frequency equal or close to the resonance frequency of the piezoelectric transformer across the driving electrodes thereof, a DC voltage is impressed upon the driving electrode to vary the resonance frequency to regulate the output voltage characteristics.

4 citations



Patent
Shimizu Yohei1
02 Apr 1970
TL;DR: In this paper, the flyback transformer coil for television receiver comprises surface-insulated wire windings, a plurality of wire layers, and an assembly of the wirings and interpositioned insulating material being impregnated with a liquid heat-setting polybutadiene resin having a lower dielectric loss at both low and high temperatures, for example 20*-150* C., and heated and hardened, thereby to deposit a hardened layer of the resin in all the layers of the coil assembly.
Abstract: Flyback transformer coil for television receiver comprises surface-insulated wire windings having a plurality of wire layers, a plurality of layers of insulating material thereby to separate adjacent layers of wound wires, and an assembly of the wirings and interpositioned insulating material being impregnated with a liquid heat-setting 1-2 polybutadiene resin having a lower dielectric loss at both low and high temperatures, for example 20*-150* C., and heated and hardened, thereby to deposit a hardened layer of the resin in all the layers of the coil assembly. The present coil has a good water, moisture and burning resistances and good insulating efficiency.

Patent
16 Sep 1970
TL;DR: In a television receiver, the line frequency keying pulses applied to the respective control electrodes of the phasefrequency comparison circuit for the line synchronism and/or the video gain control circuit are produced in an AND circuit to whose inputs are applied the line sync pulse and a line frequency pulse generated in the horizontal sweep circuit, i.e., the line flyback pulse as mentioned in this paper.
Abstract: In a television receiver, the line frequency keying pulses applied to the respective control electrodes of the phasefrequency comparison circuit for the line synchronism and/or the video gain control circuit, are produced in an AND circuit to whose inputs are applied the line sync pulse and a line frequency pulse generated in the horizontal sweep circuit, i.e., the line flyback pulse.


Journal ArticleDOI
J. A. Hornberger1, W. A. Robinson1
TL;DR: In this paper, a feedback scheme to the horizontal output tube has been used to achieve better regulation of high voltage regulation in large screen color TV (25?-90°tubes).
Abstract: One of the problems associated with horizontal deflection and high voltage systems utilizing third harmonic tuning of the flyback transformer for large screen color TV (25?-90°tubes) has been the high voltage regulation. In tube sets, the shunt regulator has been widely used; and, more recently, a feedback scheme to the horizontal output tube has been used to achieve better regulation. However, the shunt regulator has proved undesirable because of reliability, and it is a potential source of X-rays. The feedback scheme does not lend itself to transistor circuitry because the horizontal transistor is operated as a switch. Therefore, in making a transition to transistor horizontal deflection and high voltage systems, regulation becomes a problem.


Patent
04 Jun 1970
TL;DR: In this article, a surge current limiting circuitry for direct current to direct current inverters and the like of the type in which switching of transistors to reverse flux in a center-tapped output transformer is achieved by the use of a saturable core transformer.
Abstract: Surge current limiting circuitry for direct current to direct current inverters and the like of the type in which switching of transistors to reverse flux in a center-tapped output transformer is achieved by the use of a saturable core transformer. Surge currents in the saturable core transformer, as it saturates, are limited by means of switching transistors which switch the transformer drive currents to high impedance paths when the transformer saturates.

Journal ArticleDOI
01 Jul 1970
TL;DR: A detailed mathematical analysis of the operation of the television horizontal-deflection circuit is carried out in this article, where the amount of oscillatory ringing in the scanning process is expressed by functions of the components in a lossless equivalent circuit.
Abstract: A detailed mathematical analysis of the operation of the television horizontal-deflection circuit is carried out. The amount of oscillatory ringing in the scanning process is expressed by functions of the components in a lossless equivalent circuit. The fault in the customarily presumed 2.8th-harmonic tuning method is clearly shown with examples, where the ringing oscillations are supposed to be suppressed by the previous methods. A principle is presented to obtain favourable conditions for resonance frequencies to decrease underisirable ringing oscillations in the scanning process and to increase the high flyback pulses in the flyback process. Some numerical calculations based on this method are carried out.

Patent
08 Apr 1970
TL;DR: In this paper, a line deflection output stage for a television receiver utilizes a transistor or gate-controlled switch 46 which is turned on during each sweep by a switching device 11 and turned off so as to terminate each sweep, which is terminated by the negative half cycle of the square wave from winding 42, thus providing reverse breakdown of the control circuit 46 giving rapid removal of charge carriers and hence rapid turn off.
Abstract: 1,187,499 Transistor sawtooth circuits GENERAL TELEPHONE & ELECTRONICS LABORATORIES Inc 23 Oct, 1967 [1 Nov, 1966], No 48117/67 Heading H3T [Also in Division H2] A line deflection output stage for a television receiver utilizes a transistor or gate-controlled switch 46 which is turned on during each sweep by a switching device 11 and turned off so as to terminate each sweep by a switching device 12 which connects the control electrode of switching device 46 to a reverse biasing potential -V2 exceeding the control circuit breakdown voltage of device 46, a diode 47 being included in both the control and main circuits so as to prevent flow of reverse current As described, the circuit is controlled by a square wave oscillator 10 supplying anti-phased outputs from windings 41 and 42, the former turning on transistor 43 which, in turn, turns on the output stage 46 giving a linear rise of current in deflecting coils 50 Each sweep is terminated by the negative half cycle of the square wave from winding 42 which turns on thyristor 44, thus providing reverse breakdown of the control circuit 46 giving rapid removal of charge carriers and hence rapid turn off The energy in deflection coils 50 now charges the flyback capacitor 18, damping diode 48 becoming conductive after one quarter cycle and remaining conductive during the first half of the next sweep until device 46 is again turned on An EHT transformer 52 and rectifier 53 are provided


PatentDOI
12 Feb 1970
TL;DR: In this article, a thermionic tube has its cathode connected to one terminal of one winding of a feedback transformer and the other terminal is connected to negative high voltage through a load resistor.
Abstract: Apparatus for generating a rectangular wave positive pulse having an amplitude of 80 kilovolts or more in response to low voltage timing signal pulses in which a thermionic tube has its cathode connected to one terminal of one winding of a feedback transformer and the other terminal is connected to negative high voltage through a load resistor, and the other winding of the transformer is connected in series with the secondary winding of a high voltage input transformer and the series circuit so constructed is connected to the thermionic tube cathode and grid. The primary of the input transformer is connected to the output of a low power amplifier which in turn has its input coupled to a timing signal pulse source having an amplitude of the order of 10 volts.

Journal ArticleDOI
TL;DR: A flyback design has been considered an art rather than a science as discussed by the authors, and despite a great deal of published theoretical analysis, the actual development of a flyback is often done empirically.
Abstract: Historically, flyback design has been considered an art rather than a science. Despite a great deal of published theoretical analysis (Ref. 2,3, 4,5, and 6), the actual development of a flyback is often done empirically. The theory is sufficiently cumbersome and complicated to deter an engineer from using it.