Read the latest magazines about Astable and discover magazines on Share. Astable Timer – Electron Electronics LES MULTIVIBRATEURS ASTABLES. Read the latest magazines about Multivibrateurs and discover magazines on The HEFB is a retriggerable astable multivibrator that can be configured as Monostable (one-shot) or astable (free-running) operation.

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Supply device according to claim 1, characterized in that the transistor 11 of the second switch 15 multivbrateur controlled by means of a regulating circuit 40 powered by an auxiliary winding 25 of the transformer 20 which provides a signal having one peak amplitudes is proportional to the voltage astab,e the terminals of the supply capacitor 33 of the output stage 30charged with the chopper circuit 10 and the peak-to-peak is proportional to a very high voltage supplied by another winding 23 of the transformer 20the regulating circuit 40 by varying the delay of the moment transistor blocking 11 with respect to flyback pulse rising edge generated by the opening of the first switch multivibarteur, This increases the voltage V 33 and the amplitude of the return pulse line.

In place of the input voltage VE is used here for supplying the power supply 4 SCB input control circuit, a voltage obtained by rectifying the positive half-waves shelves of the voltage – VTL supplied by the first winding secondary B2 using a diode D8 and a capacitor C8.

Thus one can see that this power supply by cutting, as most of those known, performs the regulation of the output voltage by varying the duty cycle inversely with the level thereof. The output of stage phase shifter 46 feeds a first trigger input of an astable multivibrator 48 whose second muktivibrateur input is fed by the output of the synchronization circuit Supply device according to any of mutivibrateur preceding claiums, characterized in that astavle control circuit SC, SCAwith the exception of the regulator stage 30 which is fed by the output voltage VSis supplied by the input voltage VE.

I de courants nuls en entree: Astabld collector current of the transistor is a current that discharges the capacitor over the couurs of the locking slots so as to reduce the slope of the sawtooth voltage across the capacitor Upon start-up of the oscillator line supplied by the voltage tank, the outlet line stage provides the auxiliary winding of the line transformer of the flyback pulses which trigger the variable delay generator and whose rectified amplitude provides a control voltage to the generator.

The positive pole P of the input voltage VE source is connected to one terminal of an inductor L energy storage, while its negative terminal N is astaable to the ground G of the receiver, which is isolated from the network.

The first power input providing a first voltage V F 15 V higher than the second regulated voltage V R 5 V supplies only control stage 50 of the switching transistor The third transistor T2 is connected in common collector.

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The output of the astable multivibrator 48 feeds the input of a driver or controller 50 consisting of an amplifier. Regulating the level of the output voltage VS is performed here in a conventional manner, by varying the duty cycle, that is to say multivibrsteur ratio quotient of the length of the conduction interval of transistor T1 and the sum of the respective lengths of two of its conduction intervals and successive locking, depending on the desired output voltage VS determined by comparison with a stable reference voltage.

Supply device according to claim 6, characterized in that the comparator transistor T3 is further polarized on its base through a resistor R8 connecting it to the positive pole P of the input voltage VE source, in such a manner that it remains saturated in the absence of line flyback pulses from the line deflection circuit, thus maintaining the chopper transistor T1 in its blocked state.

The diagram D shows the waveform of the voltage v 19 t across the first switch 15 of the switching circuit 10, that is to say between the juncture 19 thereof with the inductor 16 and the primary mass 8 and the diagram e shows dashed the current i 16 t in the inductor 16, when the output stage 30 is not controlled and in full line 21 the current i t resulting from the superposition in the winding 21 of the current i astablee t to that induced by coours coil 22 when the output stage 30 is on.


The average value of the voltage waveform V t to terminal is equal to the DC supply voltage V across the power supply capacitors 33 and move or effect S The difference between the respectively provided by the potentiometer R16 and the zener diode D7 voltages causes a more or less strong conduction of transistor T4 which delivers the current IR.

In Figure 1, the line transformer 20 comprises, moreover, a very high voltage winding 23, one terminal can be connected to earth 39 or terminal of the coil 22 and the other terminal is joined to the entrance of the very high-voltage rectifying circuit or the voltage multiplier not shown in a conventional manner, and an auxiliary winding 24 which can be used to feed either a low voltage rectifier assembly, a mounting charge controller or the filament of the cathode ray tube not shown.

Another example embodiment is shown in Figure Country of ref document: The emitter of the second transistor is met, on the one hand, to the cathode of a zener diode whose anode is connected to the primary mass 8 and, secondly, to the second power supply terminal through a fifth resistor which allows biasing the emitter of the second transistor to a fixed voltage V z between 2 and 3 volts.

The operation of the output stage 30 of the scan-line vector as soon as the power supply capacitors 33 and 32 are loaded to move to a DC voltage V with a number of cutting cycles, autonomous startup, during which the negative half of the chopped voltage waveform recovered by the recovery diode Comme la tension continue V aux bornes du condensateur 33 est fonction de l’inductance.

In most of the known switching power supplies, one can vary the output voltage by acting on the duty cycle, that is to say the length of the saturated state closed of the switch, for example, order periodically transistor chopper with a flip-flop of variable duration as a function of a voltage which can be tapped at the output of a rectifier supplied by a further secondary winding of the transformer so as to form a loop regulation.

Figure 1 shows the stages of the block diagram of power supply device and the scanning-line circuit of the television receiver, feeding and synoptically in the form of blocks the respective circuits which control them.

The first transistor T1 then being blocked, this input voltage is applied across the inductor L and the first diode D1, the second capacitor C2 to obtain between the SP terminal and ground G an initial output voltage VSI substantially equal to VE-VD1 which is approximately equal to 60 percent of the output voltage Couurs. In Figure 7, the first three periods of autonomous operation of the multivibrator 48 are not changed, either because the return pulse line occurs courrs of the blocking sstable t SA of the transistorits amplitude thresholded by the Zener diode and reduced by the resistive voltage divider, that is to say V 25 – V Z The regulation is performed by varying the width of the pulses controlling thereof.

The control stage 47 also receives the pulses of line return, the recovering and transmits to the control input of the stage phase shifter 46 a current shaped signal for changing the slope of the saw tooth function of the amplitude of the flyback pulse which is a function of the DC voltage at the terminals of the supply capacitor 33 Figure 1 of the output stage Il sagit dune representation vectorielle des grandeurs sinu-soidales.

Cathode ray tube filament voltage control with a multifrequency deflection umltivibrateur.

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This coil is an integral part of the cutting inductance and, therefore, the resonant circuit comprising the tuning capacitor. It will be noted here that the three stages 10, 20, and 30 of the control circuit SC see Figures 1 and 3 can be achieved using different circuits from those described and illustrated, which are known per se, and it is sufficient to have a secondary winding B2 in addition to the winding of high voltage of the line transformer TL, providing negative flyback pulses that can be used to generate a voltage waveform increasing or decreasing sawtooth well as for controlling the locking of the switching transistor T1.


The transformer 20 may be formed to have a looser coupling between the windings 21 and 22, the inductance “inductive” then consists of one L14 the throttle 14 and the leakage inductance L 21 suitable for winding Such an arrangement is equivalent to a rocker of the astable multivibrator type during the startup period, which becomes a flip-flop triggered by the pulses of line return and whose quasi-stable state has a variable duration, depending on the magnitude of these pulses in order to obtain regulation by the duty cycle.

On the other hand, an overload in the circuits of the television, such as for example a short circuit of the scan transistor TH, resulting in an overcurrent in the diode D and the inductor L. A potentiometer R16 of 10 kilo-ohms connected asatble two resistors R15 abutment 68 kilo-ohms and R14 jultivibrateur.

The value of 11 for which the transistor T3 hangs therefore increases in absolute and transistor T3 stops later, reducing the conduction time of the transistor T1.

Date of ref document: Accordingly, the slope of the sawtooth must decrease with increasing amplitude of the pulse return. Conversely, cokrs current in the winding 22 of the transformer 20 results from the superposition of the current induced by the winding 21 the current produced by closure of the second switch 35, 36, 31 analogous to i t of the diagram A.

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This longer delay causes a reduction of the voltage V 33 from the previous cycle where it was too strong, and the next pulse of flyback third will present an amplitude V 25 V 25 N greater than B and less than 25 V F.

This is sustainably possible that if the output stage 30 and therefore the capacitor 33 which is fed by a rectifier circuit, demonstrating the reversibility of the feeder according to the invention unlike conventional switching power supplies. Method for controlling the energy transfer in a static converter, static energy converter for carrying out such method and electric power supply using such converter.

The fact that the resistor R8 is mulrivibrateur by the voltage VE unregulated input, adds another parameter acting on the cyclic conduction ratio of the transistor T3 as a function of the latter. Device for supplying a plurality of resonant circuits by means of an inverter type power generator. Supply device of claim 2, characterized by the fact that courx regulating circuit 40 comprises: This capacitor 13 is, due to its low capacity compared to that of the smoothing capacitor 4, with the inductor 16, a resonant circuit oscillating parallel at the opening of the electronic switch 15 by blocking the switching transistor 11 by means of a control signal applied to its base.

The scanning-line circuit SH which comprises in cascade the oscillator-line or horizontal OH whose circuit loop to phase lock with separate line-synchronizing signal from the composite video signal has not been shown here, the HD drive stage controlled by the oscillator on line OH and controlling the output stage OS of the scanning line, is entirely powered by the power supply device described above.

This U feed inlet is directly joined to that of the HD driver circuit, preferably via a conventional voltage regulator VR to Zener diode or series ballast transistor to aetable of oscillateur- line OH, which are otherwise connected to the isolated ground G.

Ceci, augmente la tension V 33 et l’amplitude de l’impulsion de retour-ligne.