SU760410A1 - Single-shot multivibrator - Google Patents

Description

The invention relates to a pulse ~ technique and can be used in the design of pulse generators.

Known one-shot containing the output transistor, the collector of which is connected through a resistor and in parallel connected between a resistor and a capacitor with a power bus and the base of the input transistor, respectively, and to the base of the output transistor connected in parallel to each other a capacitor and a diode is connected to one of the capacitor plates of the transient JC- circuit, while the base of the intermediate transistor and the first output of the diode are connected to the Collector of the input transistor, the emitter and the second output of the diode are connected to the second In the time code capacitor, the intermediate transistor collector is connected directly to the power bus [ΐ].

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The disadvantage of this one-shot is its structural complexity.

Known for simple design of the oscillator, two transistors of the same type of conductivity (input and output), interconnected by emitters, which are connected via a register to the zero bus power supply, the base of the input transistor is connected to the junction of the divider on the resistors and through a capacitor with a source of triggering pulses , and the base of the output transistor is connected via a resistor to the power supply bus and via a capacitor to the collector of the input transistor connected via a resistor to the power supply [2].

The disadvantage of this simple, multivibrator is its large recovery time.

The purpose of the invention is to reduce the recovery time.

W 760410 4

This goal is achieved by the fact that in a single-output device containing two transistors of the same type of conductivity (input and output), the emitters of which are interconnected and connected to the first common resistor terminal, and the collectors are connected to the power supply bus through the resistors, through the output transistor a capacitor with an inlet collector, an additional voltage source, opposite to the polarity of the power source, and two diode connected in series, connected between the output terminal nzistora bus and ground potential, the junction of the diodes is connected to the emitters of transistors, wherein the voltage source is connected in common to the second terminal of the resistor and the input transistor base is connected directly to zero potential bus.

The drawing shows a schematic diagram of the one-shot.

The single-oscillator contains input and output transistors 1 and 2, interconnected by emitters and connected to the first output of common resistor 3, the collectors of these transistors through resistors 4 and 5 are connected to bus 6 of power supply · E. The collector of input transistor 1 is connected to base of transistor 2 through the capacitor 7. The base of the transistor 2 through two additional diodes 8 and 9 is connected to the zero potential bus, and the common resistor 3 is connected to the bus 10 of the voltage source + E. The resistor 11 is designed to securely lock the transistor 2 into Resistant able to one-shot. In addition, there is a source 12 trigger pulses with its internal or external resistance 13, connected either to the emitter of the input transistor 1, or through a diode 14 to the collector of the input transistor. one.

In the steady state of the one-shot, transistor 1 is saturated with current flowing from source + E through resistor 3 and emitter-transistor 1, because the collector current, limited by resistor 4, is less than the emitter current, and transistor 2 is locked and the voltage on its collector is close to the supply voltage .

Reliable locking of the transistor 2 is provided by the current of the resistor 11, which creates a certain voltage drop across the open diode 8.

To convert a one-shot into a temporarily stable state, it is necessary for a short time either to exceed the emitter current of transistor 1 in the collector circuit, for example, by applying a pulse from the source 12 trigger pulses to the collector of transistor 1, or by reducing the emitter current of transistor I to a value smaller than the collector current of the transistor specified a resistor 4, for example, by applying triggering pulses to the emitter circuit of transistor 1.

In any of these cases, the transistor! coming out of saturation and transistor 2

1 _{5 is} opened by the charge current of the capacitor7. The emitter current of transistor 2 is greater than the charge current of capacitor 7 and more current from voltage source + E, and therefore the difference between the emitter current and currents of resistors 3 and 11 flows through diode 9, and transistor 1 is reliably locked by a reverse voltage across the emitter. the voltage drop across the diode 9 from the current source -E.

₂₅ After the effect of the input pulse is stopped, the one-shot remains temporarily stable until the capacitor 7 is charged through resistor 4 and the basic transition of transistor _{30 of} resistor 2. After the capacitor 7 stops charging, transistor 2 closes and transistor 1 opens with current from source + E. The capacitor 7 is discharged rapidly through the diode 9 and the emitter-collective ₃₅ Torr transistor 1, since the capacitor discharge current 7 that flows through the diode 8 and the emitter of transistor 2, the capacitor discharge rate increases because of increase in current of transistor 1. After unlocking the rapid discharge of the capacitor 7 the one-shot returns to its original state.

The scheme of the proposed one-shot allows you to set a predetermined threshold

_ί5 pickups according to the amplitude of the current supplied to the input, which is achieved by setting the ratio of the emitter and collector currents of transistor 1. In addition, the output pulse parameters _{50 are} independent from the trigger pulse parameters.

When connecting the Zener diode 15 to the collector of the transistor 1 increases the stability of the generated pulses.

_{! 5} When switching on instead of the diode 8 of the base-emitter junction of the additional transistor, the one-oscillator generates a pulse later, some time after the arrival of the trigger pulse.

Claims (1)

Claim A single-oscillator containing two transistors of the same type of conductivity (input and output), interconnected by emitters and connected to the first common-resistor output, the collectors of which are connected to the power supply bus through resistors, and the output transistor base is connected by a collector of an input transistor through resistors, that, in order to reduce the recovery time, a voltage source opposite to the polarity of the power source and two diodes connected in opposite directions were added to it 0410 6 therefore, connected between the base of the output transistor and the zero potential bus, the connection point of these diodes is connected to the emitters of the transistors, the voltage source is connected to the second common-resistor, and the base of the input transistor is directly connected to the zero potential bus.