SU429510A1 - GENERATOR RECTANGULAR PULSES - Google Patents

Description

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The invention relates to a pulse technique.

A known generator of rectangular pulses, which contains the time specifying a capacitor connected in series with a current-stabilizing charging stage, and a discharge stage.

However, the known generator has a limited range of adjustment of the pulse duty ratio and the dependence of the pulse repetition frequency on the pulse duration.

The aim of the invention is to expand the range of adjustment of the pulse duty ratio, ensuring the independence of adjustments of the duration of the output pulses and their repetition rate.

For this purpose, the cathodes of two diodes are connected to the anode of a silicon one-way key, the anode of one diode is connected to one of the time of the driving capacitors, the anode of the second diode is connected to the second time by the driving capacitor and the base of the transistor connected in. the common emitter circuit, the control electrode of the silicon single-sided key is connected via a resistor with the positive pole of the power source, and via zener diodes - with the corresponding emitters of the current-stabilizing cascades transistors.

The invention is illustrated in the drawings.

FIG. 1 shows a circuit diagram of a square pulse generator; in fig. 2 - voltage diagrams on circuit elements.

The square pulse generator contains the time setting capacitors I and 2, connected between the source of the negative voltage i and the collectors of the transistors 3 and 4, respectively, which are current-stabilizing charging stages.

A resistor 5 is connected between the emitter of transistor 3 and the positive pole of the power source E, and a resistor 6 is connected between the emitter of transistor 4 and the same pole of the power source. Resistors 5 and 6 can be variable, including voltage-controlled variable resistance components. (for example by field effect transistors).

A transistor control Uynp is applied to the base of transistor 3. and to the base of transistor 4, the control voltage Uynp Capacitor 1 is connected via diode 7 to the anode of silicon single-sided key 8, and capacitor 2 is connected through diode 9 to silicon anode of single-sided switch 8, and the cathodes of diodes 7 are connected to the anode of key 8 9. The capacitor 2 is also connected to the base of the transistor 10, whose collector load is a resistor 11. The control electrode of the silicon single-sided switch 8 is connected to the positive pole of the power source through a resistor 12, through a zener diode 13 to a transistor emitter 3 and through a zener diode 14 - the emitter of the transistor 4, and to the control electrode of the zener diode 13 are connected anode 14. The cathode of the silicon unilateral switch 8 is connected to the negative pole of the power source EI. The generator works as follows. After switching on the supply and control voltages, capacitors 1 and 2 are charged by the collector currents of transistors 3 and 4, respectively. The voltages on the capacitors increase (see Fig. 2, plot f / c), and the voltage on the control electrode of the silicon single-sided key 8 relative to its cathode is fixed and close to C / n - the unlock voltage (switch), due to the stabilizing properties of the transition control electrode-cathode of a silicon single-sided key (f / A plot), since a current flows through this transition, which is determined by the resistance of the resistor 12.

Until the voltage on the capacitor 1 reaches f / n, diodes 7 and 9, as well as zener diodes 13 and 14, are closed. However, until the voltage on the capacitor 2 exceeds the voltage EI, the transistor 10 is closed and the voltage on its collector is equal (see Fig. 2, plot and B).

For normal operation of the generator, it is necessary that and so where Ta is the charging time of capacitor 2 to i — the opening time of transistor 10, and TI — the charging time of capacitor 1 to -4 — the opening time of silicon single-sided switch 8.

When these conditions are met at time i, transistor 10 opens and the voltage across its collector abruptly drops to almost zero. After that, the voltage on the capacitor 1 continues to increase and at time f2 exceeds Un, as a result of which diode 7 and silicon single-sided key 8 are opened. The opening of the silicon single-sided key 8 occurs like an avalanche, so the capacitors 1 and 2 are quickly discharged through it and the diodes 7 and 9, respectively. At the same time, on the control electrode of the silicon single-sided switch 8, the voltage abruptly decreases, as a result of which the zener diodes 13 and 14 open, which causes a decrease in the voltage at the emitters of transistors 3 and 4, respectively, and the closing of these transistors.

Due to this, after the moment tz, only the discharge current of capacitors 1 and 2 flows into the anode of the silicon single-sided key 8, which quickly decreases and reaches the holding current / beats by the moment the s, therefore the silicon single-sided key 8 is closed. At this point, capacitors 1 and 2 have time to discharge.

The discharge of the capacitor 2 immediately after the moment / g causes an abrupt closing of the transistor 10, as a result of which the voltage on its collector again takes on a value. Closing the silicon single-sided key 8 at the time causes an abrupt increase in voltage on its control electrode and anode, so the diodes 7 and 9, as well as the zener diodes 13 and 14, are closed and transistors 3 and 4 are opened, due to which the capacitors 1 and 2 start to charge again to press. Further, the processes are periodically repeated. In addition, each period during the discharge of the capacitor 1 and 2 and the charge of the capacitor 2 at the collector of the transistor 10 produces positive rectangular pulses, the repetition period of which is equal to the sum of the charge time of the capacitor 1 TI and the time of the discharge of capacitors 1 and 2 Tr, t . e. r Ti + Tp, and the duration of which is Gz Tr + T2 (see Fig. 2, plot Us) Pa Pa of the control electrode of a silicon single-sided key 8 with the same repetition period produces negative rectangular pulses of duration Tp (see Fig. 2, plot UA).

Changing the control voltage / 7pcr, or the resistance of the resistor 5, it is possible within wide limits to regulate the charge current of the capacitor 1, and hence the frequency of repetition of the output pulses, without affecting their duration.

By varying the control voltage or the resistance of the resistor 6, it is possible to regulate the charge current of the capacitor 2 within wide limits, and hence the duration of the output pulses on the collector of the transistor 10, without affecting their repetition frequency.

Closing transistors 3 and 4 during the discharge of capacitors 1 and 2 using Zener diodes 13 and 14 allows you to extend the range of adjustment of the duration and repetition frequency of the output pulses, as it closes the silicon single-sided key 8 with charge currents even much higher than / beats.

Subject invention

A rectangular pulse generator containing two times of a driving capacitor, which are connected in series with current stabilizing charging stages on transistors, and a discharge cascade on a silicon single-sided key, characterized in that, in order to extend the range of adjustment of the pulse duration, to ensure the interdependence of adjustments to the duration of output pulses and their repetition frequency, the cathodes of two diodes are connected to the anode of a silicon one-sided key, the anode of one diode is connected to one of the time The capacitors, the anode of the second diode is connected to the second time by the driving capacitor and the base of the transistor connected according to the common emitter circuit, the control electrode of the silicon single-sided key is connected via a positive zero resistor of the filament source, and through zener diodes to the corresponding emitters of the current-stabilizing transistors.

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