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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According to the invention, the duration t S of the saturated state of the switching transistor 11 and the conductive state of the diode 12 and, therefore, the ratio of this length to that of the full cycle T H line period or the t B of the locked state is constant and chosen so as to make the peak amplitude of the voltage pulse 19 v, applied to the collector of transistor 11 during the blocking interval t B, substantially less its voltage collector-emitter breakdown in the off state VCEX which can now exceed volts.

Entree inverseuse – 3: The output stage includes a second and a third NPN transistors and During periods of the outward scan line, when the second bidirectional switch 35, 36 of the output stage of the scan 30 is closed conductivethe terminals of the winding 22 of the the transformer 20 are joined directly to those of the capacitor 33 which therefore receive power supplied from the chopper circuit A less than or equal to one hundredth to this report gives satisfactory results.

The current I must be souistrait the current I charging the capacitor during the entire time when the amplitude of the flyback pulse exceeds the voltage V BE.

This assembly thus connected elements constitutes the output stage OS of the scan line whose operation is well known and does. Therefore, the diode D1 conducts from the moment of blocking of the transistor T1 a linearly decreasing current until the disappearance of the energy stored in the form of current IL in the inductor, which charges the second capacitor C2 to a VS output voltage higher than multivibratejr input voltage VE.

The base of the first transistor is also coupled to the primary mass 8 via a second capacitor Static power supply device of an electrofilter for electrostatic dust precipitation.

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Supply device according to any of claims 1 to 6, characterized in that the direct supply voltage of the control circuit SCBwith the exception of one of the inputs of the regulator stage 30 which receives the output voltage VSis supplied by a secondary winding B2 of the line transformer TL through a rectified circuit composed of a diode D8 and a filter capacitor C8.

FR Free format text: Diagram B shows the waveform of the voltage v t at terminal of the winding 22, which is also that across the second switch 35, The control stage 47 also receives the pulses of line return, the recovering and transmits to the control input of the phase shifter 46 a floor should sign shaped current 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 For this purpose, an autonomous current supply voltage source 51 is connected to terminals 1, 2 alimenation the AC network and tensions it provides supply the power supply terminalsand of the control circuit During this same time interval, the second transistor of multivibrator 48 and the second transistor of driver stage 50 are saturated, and the first and third transistors of this stage 50 are blocked so that the base of switching transistor 11 is poled to conduct.


When the second transistor of multivibrator 48 has switched from its saturated state to its off state, its collector voltage is equal to the stabilized voltage V R and the diode is blocked.

Astabble of cuors document: Note here that the power winding 21 may be connected between the terminal 6 of the capacitor asable and the choke coil 14 in two opposite directions, so that the flyback pulse may appear on the junction of self 14 with opposite polarities which shows two phase Actions on the voltage V 21 t with respect to the current i 21 t of this winding T 48 A ’19 where V max is the peak amplitude of the collector voltage at terminal 19the t B of the switch off-time 15 VA max the maximum supply voltage supplied by the rectifier 5 and T 48 A autonomous period of the multivibrator 48, T 48 A being greater than T H.

Le diagramme C de la figure 2 montre la forme d’onde correspondante du courant IL parcourant l’inductance L. The comparator transistor becomes conductive when its VBE becomes positive and the collector current will be much stronger than is the amplitude of V F 25 to which the load capacitor The transistor switch 11 is met here by its collector 1 one terminal of the inductor 16 whose other terminal is connected to the positive terminal 6 of the source 5 supplying the DC voltage supply V ,, its emitter 7 to the negative terminal of the source 5 which constitutes a mass, called the primary hot or 8, connected to the AC mains, but insulated from the TV The average value of the voltage waveform of v t to terminal is equal to the DC supply voltage V across the power supply capacitors 33 and move or effect S The other terminal of the inductor L is connected on the one hand, to the collector of a first bipolar switching transistor T1 of the NPN type, whose emitter is connected to ground G, and on the other hand, the anode of a first diode D1 whose cathode is connected to the positive plate of a second filter capacitor C2.

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Since the conduction time of the switch 15 is extended, the energy stored in the inductor 16 increases. When the current IL passing through the first diode D1 becomes zero at time t3, the collector-emitter voltage VCE of the first transistor T1 becomes equal to the unregulated input voltage VE to the next release time of the transistor T1, and the first diode D1 remains reverse biased until time of subsequent relocking thereof.


Boukaddid Cours electrocinetique sup TSI3. The rising edges of the pulses supplied by the output of the rocker 41 substantially coincident with those pulses flyback, their descent or falling edges that occur with variable delays with respect to the first are used kultivibrateur trigger, possibly through an inverter stage, a second flip-flop 45 whose output feeds the base of chopper transistor 11 to block it.

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The astable multivibrator 48 is, preferably, synchronized in frequency with the output stage of the scanning line 30 in a manner that will be multivbrateur later, with the synchronizing circuit 49 which feeds its synchronization input Suitable for operating limits, particularly in view of the value of the inductance L, the cyclic ratio of the durations t2-t1 is varied between mjltivibrateur, where the input voltage VE is equal to the output voltage nominal Adtable, and about two-thirds, where the maximum power is supplied for a minimum voltage at the input.

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. La grandeur physique G ne varie pas dans le temps: When the multivibrator 48 starts to oscillate, it provides at its output constituted by the collector of the second transistorsquare-wave signals with two levels V R and V CEsat Lowest which causes, through the diode of couplingthe blocking of the first transistor of the control stage P en remplacant ik et ukpar ik t astalbe uk t.

Switch mode vertical deflection circuit for a videofrequency receiver, and receiver comprising such a circuit. The first input of the differential amplifier is constituted here by the base of transistor T4 is biased by a voltage divider circuit consisting of a fifteenth resistor R15 4.

The invention will be better understood and its other objects, features, and advantages will be apparent from the following description and the accompanying drawings relating thereto, given by way of example, in which: We also know that it is difficult to achieve switching power supplies for proper operation when it is not fully charged to power, for example, a remote control receiver in the standby state.

Ref legal event code: Lapsed in a contracting state announced via postgrant inform. The capacitor C3 serves to accelerate the blocking promoting transmission to the base of T1 steep transitions negative flyback pulses.