Showing papers on "Flyback transformer published in 1969"

Transformer Inrush and Rectifier Transient Currents

Abstract: Formulas are developed and curves given for the magnetizing inrush current for a single-phase transformer. Series system inductance and resistance are included. The transformer is assumed to have no exciting current below saturation and constant saturated inductance above saturation. The formulas apply to circuits with either low or high resistance. The curves permit calculation of peak, average, or rms current, and show how these currents decay with time. The theory can also be used for certain cases where there is direct current in a transformer winding and also for certain types of phase controlled rectifiers supplying a series resistance and inductance load.

Circuit using capacitor and switch on primary winding of transformer for regulating voltage on secondary winding of transformer

Abstract: A SYSTEM DETECTS CHANGES IN THE OUTPUT VOLTAGE ON THE INPUT SIDE OF A TRANSFORMER USED BY THE SYSTEM AND GENERATES A CONTROL SIGNAL IN RESPONSE TO THE CHANGE FOR CHANGING THE POWER TRANSFERRED TO THE OUTPUT SIDE OF THE TRANSFORMER. THE INPUT AND OUTPUT HAVE GROUND ISOLATION. AS A RESULT OF CONTROLLING THE POWER TRANSFERRED TO THE OUTPUT SIDE, THE OUTPUT VOLTAGE IS MAINTAINED AT A CONSTANT LEVEL.

Instant-on circuitry for solid state television receivers

Abstract: In a solid state television receiver, the primary windings of a main and an auxiliary transformer are both coupled across an AC input line. A single-pole, single-throw switch interposed in one conductor of AC input line subsequent to auxiliary transformer takeoff point permits deenergization of main transformer primary winding without interrupting energization of auxiliary transformer primary winding. One secondary winding of main transformer provides AC input to television receiver power supply. Kinescope filament is energized by circuit comprising a secondary winding of auxiliary transformer in series with an additional secondary winding of main transformer. When switch is closed, receiver is ''''on'''' with power supply operative and kinescope filament receiving full rated voltage comprising sum of secondary contributions. When switch is open, receiver is in ''''standby'''' condition- with power supply inoperative, but kinescope filament energized at reduced level representing contribution of auxiliary transformer secondary alone. In remote control embodiment, auxiliary transformer has additional secondary winding providing AC input to remote control receiver power supply.

Apparatus having a television camera tube and television camera tube for use in such an apparatus

Abstract: A television camera tube which has an anti-comet-tail electron gun. In such tube a target plate (11) is line scanned by a focused electron beam which is at a cathode voltage of typically zero volts to stabilise the scanned area of the target plate (11) at that voltage and in so doing producing an output signal. During line flyback, the cathode voltage is increased to 5 V and the beam current is increased so that the target plate (11) is stabilised at that voltage. By this means the effects of moving high intensity lights can be mitigated. However if the electron beam is focused during flyback then intense damage can be done to the photo-conductive layer of the target plate. A television camera tube is described in which the electron gun (14) is a multi-spot triode electron gun comprising a cathode (15), a multi-apertured control grid (16) and a multi-apertured accelerating anode (17). During line scanning a single low current electron beam is produced from the centre of the cathode (15) and during line flyback a plurality of low current electron beams are produced to form a large spot which does not damage by ion bombardment the photo-conductive layer of the target plate (11).

Television receiver agc system keyed in response to time coincidence of sync and flyback pulses

Abstract: Under normal operating conditions a coincidence circuit produces keying pulses, for an AGC system of a television receiver, only when the flyback pulses from the receiver''s horizontal sweep system occur concurrently with the horizontal sync components from the sync separator. The magnitude of the developed AGC voltage is held constant between keying pulses. This arrangement precludes sampling of video information, with a resulting false measure of received signal strength and an erroneous magnitude for the AGC voltage, which takes place in a conventional flyback pulse-keyed AGC system when the horizontal oscillator is out of synchronism with the sync pulses. During transient conditions, when there is a very fast and substantial increase or decrease in received signal strength causing a loss of sync pulses at the separator output, keying is achieved in the disclosed AGC system in response to the flyback pulses alone.

Dc arc welder

Abstract: A DC welding system wherein DC power is applied to an electrode through a rectifier and the output of the rectifier is controlled by a transformer tap-changing system supplying power from a supply transformer through a second transformer in series with the rectifier. The tap changing system is controlled by selectively applying power to controlling relay coils through a diode matrix.

Stabilized voltage-step-down circuit arrangement

Abstract: A rectified supply voltage from an AC utility outlet is chopped under the control of a recurrent pulse in the load circuit, specifically the flyback pulse of the horizontal sweep circuit of a television receiver, with the aid of a normally blocked chopping transistor connected to be unblocked by an intermittent biasing current from a secondary winding of a transformer whose primary winding acts as an inductance of a smoothing network for the chopped supply voltage. The resultant reduced output voltage is stabilized by the provision of a Zener diode in the input of either the chopping transistor or an ancillary transistor in series therewith.

Fluorescent lamp apparatus including inverter circuit and reflector

Abstract: An electronic inverter circuit particularly suitable for energizing fluorescent lamps from a direct current power supply wherein transistors are employed as switches in a self-excited oscillator circuit. The circuitry includes a transformer core alternately saturable at a high frequency under the control of the transistor switches, the transformer including a feedback winding controlling operation of the transistors. A transformer secondary winding supplies a high voltage output to the fluorescent lamp, and the high voltage output includes a conductor disposed adjacent the lamp to reduce the voltage required to initiate an arc therein.

Circuit arrangement for generating a line frequency parabolically modulated sawtooth current of field frequency through a field deflection coil

Abstract: A TV deflection system that includes a circuit for generating a sawtooth field current parabolically modulated at the line frequency in the field deflection coil. The circuit includes a resonant circuit composed of a capacitor and the field deflection coil with a resonant frequency that is approximately one fifth of the line frequency for deriving the parabolic modulation component of line frequency. The sawtooth field deflection generator periodically excites the resonant circuit via a bidirectional electronic switch that is periodically switched in synchronism with the line flyback pulses.

High efficiency regulated oscillator circuit having a substantially sinusoidal waveform

Abstract: A regulated oscillator circuit for producing a predetermined high voltage output employs a switching transistor for supplying current to a high-voltage transformer and for receiving feedback current from the same high-voltage transformer. A diode is placed in series between the switching transistor and the transformer primary such that the transistor conducts substantially no current at times during predetermined half-cycles of oscillator operation. However, the transistor is switched by feedback to an on condition during each nonconducting half-cycle whereby it will deliver current to the transformer in a zero voltage condition. The period during which current is delivered to the transformer is determined by a control circuit which turns off the transistor at a selected time during each cycle of operation in accordance with the output level produced. A voltage doubler circuit is driven by the transformer and provides a DC output level.

Low b{30 {0 start circuit for line-operated receiver

Abstract: A switching transistor is provided for a solid-state lineoperated television receiver which allows the low B+ voltage requirements of the receiver to initially be supplied from the high B+ through the turned-on switch transistor and subsequently on switching of the transistor to its nonconductive state, the low B+ requirements of the receiver are met by rectifying the horizontal flyback transformer voltage pulse.

Voltage-stepdown circuit arrangement for television power supply

Abstract: In order to provide a reduced output voltage for feeding a transistorized load, a rectified supply voltage from an AC utility outlet is chopped under the control of a recurrent pulse in the load circuit, specifically the flyback pulse of the horizontal sweep circuit of a television receiver, with the aid of a normally blocked transistor connected to be unblocked by an intermittent biasing current from a secondary winding of a transformer whose primary winding acts as an inductance of a smoothing network for the chopped supply voltage.

Automatic voltage regulator with fast acting circuit

Abstract: An automatic voltage regulator of the type having a buck-boost transformer which is rendered exceedingly fast acting to prevent excessive changes in the value of the output voltage caused by a sudden exterior change of condition. The regulator includes a fast acting circuit that immediately responds to a sudden change of the output voltage and acts to nullify the delayed reaction of the buck-boost transformer to adjust to the sudden change until the detector circuit for the transformer has responded to the changed condition and caused the value of output voltage to again be at its selected value under the control of the transformer.

Protective system for capacitive voltage transformers including a circuit for t{d fh-coupling

Abstract: A capacitive voltage transformer comprises a transformer having its primary winding connected across an intermediate section of a plurality of capacity sections connected in series between a high voltage line and ground to form a voltage divider. The transformer is provided with a protective circuit which serves to switch in a protective damping burden on the transformer in the presence of transient oscillation phenomena, and the circuit connections between the transformer primary and the intermediate capacity section include a choke coil and a low-ohmic blocking coil to improve the transformer for coupling high frequency signals to the line for carrier type communication.

Stabilized power supply with dc voltage step-down for transistorized television receivers and the like

Abstract: A rectified supply voltage from an AC utility outlet is chopped under the control of a recurrent flyback pulse from the horizontal sweep circuit of a television receiver with the aid of a normally blocked chopping transistor in series with an ancillary transistor, the two transistors being of like conductivity-type and having their bases conductively interconnected by a high-ohmic resistor. A trigger pulse is periodically applied between the emitter of the ancillary transistor and the base of the chopping transistor through a secondary winding of a transformer whose primary winding acts as an inductance of a smoothing network for the chopped supply voltage. A differentiation circuit connects the collector of the ancillary transistor to the emitter of the chopping transistor, a Zener diode in the input of the ancillary transistor stabilizing the system against fluctuations in driving voltage.

Interconnecting apparatus with impedance insertion means for electric power systems

Abstract: An interconnecting apparatus for electric power systems wherein two electric power systems are connected to each other with a series transformer and the secondary winding of the series transformer is energized with a compensating voltage whose value and polarity are such that it cancels the voltage drop developed across said transformer when said electric power systems are normally operating. The compensating voltage is derived from the secondary winding of an exciting transformer inserted between the central point of the series transformer and the earth. The secondary winding of the series transformer is connected in delta and the secondary winding of the exciting transformer is star-connected. If it is necessary, the exciting transformer may be provided with a tertiary winding to control the voltages of the respective power systems by the voltage of this tertiary winding.

Circuit arrangement for producing a line-frequency sawtooth-current having a field-frequency-varying amplitude in a television display device

Abstract: A TV deflection circuit for producing a line frequency sawtooth current whose amplitude varies at the field frequency said variation being approximately parabolic to provide East - West raster correction for any pincushion distortion and approximately sawtooth shaped to provide color correction in the case of a color TV tube. The circuit includes a modulator having an electronic switch controlled by a line frequency signal. During the forward stroke of the constant amplitude sawtooth current supplied by a line deflection current generator to the line deflection coil, the switch connects a field deflection current generator to a resonant circuit including the parallel combination of a capacitor and an inductor. The inductor comprises either the line or field deflection coils, or both. The resonant circuit has a resonant period that is approximately twice the flyback time of the line frequency deflection current.

Beam current limiting circuit for a cathode-ray tube

Abstract: A beam current limiting circuit for a cathode-ray tube (CRT) having at least a cathode, a grid and an anode comprising an anode circuit having a fly back transformer including a primary coil and a secondary coil, a power source, a high voltage rectifier for rectifying flyback pulses generated across the secondary coil, a beam current responsive means inserted between the power source and the secondary coil, a grid bias means, and switching means. The beam current responsive means is connected to the switching means and generates a control voltage whose value is so determined to be lower than the grid bias voltage while the beam current is larger than a predetermined value. The switching means is responsive to the control voltage and changes its conductive or nonconductive condition to supply the control voltage to the grid when the beam current exceeds the predetermined value, so that the beam current is prevented from exceeding the predetermined value.

Power supply for heating magnetron

Abstract: A high frequency magnetron apparatus for use in heating ovens with an improved power source device which comprises a transformer for stepping up a source voltage, a magnetron disposed on the secondary side of the transformer, and a circuit positioned on said secondary side, consisting of a condenser and diode and arranged in such a manner that when there is supplied a voltage in one direction from the poser source provided on the secondary side of the transformer, the condenser is charged and that when there is supplied a voltage therefrom in the opposite direction, the secondary voltage of the transformer is combined with the charge voltage of the condenser to be impressed on the magnetron.

Apparatus for generating a high voltage

Abstract: An apparatus for generating a high voltage which includes a transformer, a rectifying circuit connected to the transformer, a high voltage output terminal connected to the rectifying circuit, a foamed insulator molded into the space between the transformer and the components of the rectifying circuit with the exception of the high voltage output terminal, and a container insulated by the foamed insulator from the high voltage components and electrically grounded.

Improvements in or relating to Transistor Scanning Circuits for Television Receivers

Abstract: 1,162,816 Transistor sawtooth circuits ELECTRIC & MUSICAL INDUSTRIES Ltd 21 Nov, 1966 [19 Nov, 1965], No 49151/65 Heading H3T In a line deflection stage for a dual-standard television receiver, the supply voltage to terminal 6 is arranged to be reduced when the circuit is operating on the lower (405) line standard, components 8, 9 being included to prevent breakdown of the output transistor 2 by higher amplitude flyback pulses caused by the reservoir capacitor 7 temporarily retaining the previous higher voltage when changing to the low frequency standard

Three-phase tap-changing transformer system

Abstract: THE NUMBER OF GATE-CONTROLLED SEMICONDUCTOR A-C SWITCHING DEVICES (INVERSE PARALLEL CONNECTED THRYSTORS OR TRIACS) IN A THREE-PHASE TAP-CHANGING TRANSFORMER SYSTEM IS MINIMIZED BY SEQUENTIALLY USING THE SAME STATIC SEMICONDUCTOR SWITCHING DEVICES IN COMBINATION WITH APPROPRIATE SWITCHING DEVICES HAVING RELATIVELY MOVABLE CONTACTS FOR SEQUENTIALLY EFFECTING TAP-CHANGING OPERATIONS IN ALL THREE PHASES OF A Y-CONNECTED TRANSFORMER WHOSE WINDINGS ARE TAPPED.

Automatic synchronizing systems for sampling devices

Abstract: In a sampling device including a synchronizing device comprising a synchronizing circuit, a sampler, an oscilloscope, and a synchronism control circuit having a differentiation circuit to differentiate the output from the sampler to vary a variable element in the synchronizing circuit whereby to stop variation of the variable element and to maintain the same in the stopped condition upon reaching synchronism there is provided means to stop the operation of the synchronism control circuit over the flyback interval of a low-speed sawtooth wave supplied to one deflection axis of the oscilloscope to prevent loss of synchronization which otherwise tends to occur during the flyback interval.

Pulse regulator controlled from voltage multiplier

Abstract: In a television receiver in which the high voltage power supply for the picture tube includes a voltage multiplier coupled between the retrace pulse output of the horizontal sweep circuit and the second anode of the picture tube, a circuit for automatically regulating the pulse output of said sweep circuit comprising a pulse transformer having a primary winding connected between the multiplier reference terminal and ground, and a rectifier and time delay filter coupled between the pulse transformer secondary winding and the grid bias circuit of the horizontal output amplifier. The pulse transformer develops voltage pulses from the multiplier which, when rectified, provide a control voltage which is a function of picture tube beam current. Application of this control voltage via the filter to the bias circuit is operative to provide the desired pulse regulation by controlling the grid bias of the horizontal output amplifier.

Flyback System for a Constant Velocity Mössbauer Drive

Abstract: A flyback system is described for use with a Mossbauer drive transducer of the coupled loudspeaker type operating at constant programmed velocity. A flyback control waveform is generated which quickly returns the transducer to its starting position and reestablishes the programmed velocity without exciting mechanical resonances. In addition, the range over which the velocity is maintained constant and counting is permitted is automatically held constant, independent of the programmed velocity, to eliminate systematic errors that would result from a correlation between average position and velocity.

Experience in Europe with Selenium High Voltage Triplers for Color TV Sets

Abstract: For more than a year now many leading European manufacturers have been using the particularly economic voltage tripler circuit in their production receivers instead of the more conventional circuit with high voltage rectifier and shunt regulator tubes. The tripler circuit is described in detail. Also covered are the various aspects governing the design of an associated flyback transformer and high voltage tripler unit. The advantages and disadvantages of selenium/ silicon rectifiers and ceramic/metallized Mylar r capacitors are discussed. The problems involved in selecting suitable encapsulating material are dealt with. Specific characteristics of the deflection circuit with high voltage multiplication are explained. Other possibilities of voltage multiplication employing the doubler or quadrupler are briefly described. Finally details are provided of experience so far accrued in the laboratory, production lines and in the field.

Transformer Performance under Rectified Load

Abstract: Introduction Large-scale application of semiconductor rectifying devices in power and control systems calls for analysis of transformer performance in these circuits. Although some results are available in literature, (1, 2) they are not detailed and mainly refer to non-controlled rectifiers. The present investigation is an attempt at analysis of one phase rectifier transformers under controlled and non-controlled loading, using a linearized magnetic characteristic. Saturation isconsidered by quoting and comparing experimental results and also by considering the magnetization current using a function relationship for the B-H characteristic.

Electric furnace for arc melting

Abstract: An electric furnace for arc melting having electrodes connected to a main source of electrical power. A transformer having high voltage windings and low voltage windings is provided. There is means for independently connecting the electrodes to the low voltage windings of said transformer, and means for connecting the high voltage windings of the transformer to power factor correctional devices. The transformer is a three phase transformer and there are a plurality of power factor correctional devices connected to the high voltage winding of each phase of the transformer. The power factor correctional devices are preferably capacitors. Circuit breakers are provided for connecting the capacitors to the high voltage windings and disconnecting them therefrom and for changing the amount of capacitance connected to the high voltage windings.