SU1252922A1 - Pulse generator - Google Patents

Abstract

The invention relates to the class of relaxed short pulse pulse generators and is intended for use in automation devices and pulse devices. The aim of the invention is to improve the stability of the output pulse frequency. In the device containing the transistor I p - p - n-type, diode 3 ,. output bus 2, resistors 4 and 12 ,, power supply voltage 5, transistor 6 p - p - p type, zener diode 7, capacitor 8, to achieve the purpose of the invention, by stabilizing the pause duration, resistors P and 16, diodes 9, 10, 13 and 14 are inserted , zener diode-15. The pulse duration is determined by the discharge time of the capacitor through the resistors of the resistor 11, it is significantly shorter than the pause duration, therefore, the frequency stability has almost no effect. The generator has a high duty cycle of 50-50. The invention makes it possible to significantly (5-10 times) reduce the dependence of the pulse frequency on temperature, on the supply voltage, as compared with the base object. silt 5 ft 3 v with

Description

I

The invention relates to the class of short pulse n relaxation generators and is intended for use in automation devices and pulsed technology.

The purpose of the invention is to increase the frequency standard of the output pulses following stabilization of the pause duration.

The drawing shows a circuit diagram of a pulse generator.

The generator contains the first transistor 1 p - p - p - type, the emitter of which is connected to the common bus, and the collector - to the output bus 2, the cathode of the first diode 3 and through the first resistor 4 - to the power bus 5, the second transistor 6 p - n - p-type, the collector of which is connected to the emitter of transistor I, the base is connected to the anode of diode 3 and the cathode of the first zener diode 7, capacitor 8, and the connected emitter of transistor 6 to the anode of zener diode 7, second 9 and third 10 diodes and a third resistor 11 connecting the anode of the Zener diode 7 with the common P1INA and the power bus, respectively, the second a resistor 12, the first terminal of which is connected to the emitter of the transistor 6, and the second through the fourth I3 and fifth 4 diodes connected in series to the cathode of the second Zener diode 15 and through the fourth resistor 16 to the power bus, the anode of the Zener diode 15 connecting to the base of the transistor 6o

The pulse generator works as follows

In the initial state, the capacitor is discharged, and transistors 6 and 5 are closed. The capacitor 8 is charged from the power source along the circuit: bus 5 pi

tany, resistors 16 and 12, capacitor 8, diodes 9 and 10, a common bus, the potential difference from which the capacitor is charged, is stabilized by zener diodes 7 and 15 and direct-displaced diodes 13 and 14

When the voltage on the capacitor exceeds the sum of the stabilization voltage of the Zener diode 7 and the threshold voltage of the junction emitter-base transistor 6, the latter opens, the collector current of the transistor 6 opens the transistor. When the voltage at the output of the generator 2 becomes less than the voltage at the cathode of st5

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529222

bilitron 7, diode 3 is opened and an avalanche-like process of switching and saturation of transistors 6 and 1 occurs due to the positive feedback between the bases and collectors of these directors. The capacitor 8 is discharged through the transceivers 6 and 1, the power supply and the resistor 11. Because the voltage drop on the saturated transistors 6 and} is approximately equal to the voltage drop on the diodes 9 and W, the capacitor discharges almost completely (i.e. the voltage on the capacitor is zero), after which an avalanche-like process of closing the transistors occurs and a new charge cycle of the capacitor 8 begins.

The duration of the pause between pulses is determined by the expression

-RC3n H rl2Ug -U, Co), -2U,

razheniem

where is R C

and

and"

and

9S resistor value 52; capacitor capacitance 8; stabilization voltage: 15 stabilizers; voltage drop across the diode,. biased in the forward direction;

threshold voltage of opening of the emitter junction of the transistor 6j - residual voltage on

condenser 8.

Taking into account that U (o) 0 and over a wide range of temperatures and supply voltages, the duration of the pause between pulses is determined by

razheniem

t.RCln2 and has high stability;

The pulse duration is determined by the discharge time of the capacitor through the saturated transistors and the resistor 1I and is significantly shorter than the pause duration, therefore the frequency stability is almost not affected (the generator has a high duty cycle of 50-500)

Compared with the known admixture, the proposed one allows significantly (by a factor of 5–10) to reduce the dependence of the pulse frequency on both temperature and supply voltage.

Claims (1)

Invention Formula The pulse generator containing the first transistor p - p - n - type, the emitter of which is connected to the common voltage, and the collector - to the cathode of the first diode, the output bus and through the first resistor - from the remote power supply, the second transistor p - p - p-type, the collector of which is connected to the base of the first transistor, and the base to the anode of the first diode and the cathode of the first Zener diode, the second emitter transistor is connected to the anode of the first Zener diode through a capacitor and a second resistor, the first output of which is connected to the emitter of the second transistor; In order to increase the frequency stability of the output pulses, the third and fourth resistors were introduced into it, the second Zener diode, the anode of which is connected to the base of the second transistor, connected successively to the second and third diodes connected between the anode of the first Zener diode and the common ground the anode of the first Zener diode is connected to the power bus through a third resistor, the second output of the second resistor is connected to the power bus through a fourth resistor, and also connected in series the fourth and fifth diodes, gk; e between the second output of the second resistor and the cathode of the second Zener diode.