SU604137A1 - Square pulse generator - Google Patents

Description

the resistor-capacitance circuit of the second cell is connected by a resistor to the collector of the output transistor of the first cell, the middle one; point to the base of the input transistor of the second cell, a capacitor - to the power supply bus

and to the collector of the output transistor of the second cell, respectively, through a resistor and a series of diode and a resistor, the midpoint of which is connected to the base and through a resistor with an emitter of a transistor switch connected to the base of the other transistor switch, the collector of which is connected transistor first cell.

FIG. 1 shows an electrical circuit of the generator, and FIG. 2 - time diagram of his work

The oscillator is made up of two similar relaxation cells, the first of which contains the timing chain from resistor 1 and capacitor 2, input transistor 3, resistive voltage relay from resistors 4.5 of resistor 6 of output transistor 7, the collector of which is connected to the output bus 8 of the generator. The second relaxation cell contains the timing chain of resistor 9, capacitor 10, resistor 11, input 12 and output 13 / transistors. In addition, the generator contains two different types of transistor switch, made on the basis of i 4 and transistors. 15 and {Eesistors 16 J; nineteen,. j as well as resistors 2O - 23, diodes 24 and 5 with the collector of the key transistor 14 connected to the encoder bus 26 of the generator, and the emitter of this transistor connected to the supply bus 27.

The generator of rectangular pulses works as follows,. ,

When the power supply voltage (E j) is connected to the bus 27, all the transistors for some time remain in the closed state of the scientific research institute, and through the resistor 1 the capacitor 2 will be charged to the potential (lu.,) Vmvtg. tera of transistor 3 (fig. 2a),: formed by a voltage divider cf of resistors 4.5. Capacitor 2 is also charged through resistor .6. However, its nominal is several orders of magnitude less than the nominal value of resistor 1, therefore, the constant charge time 11 of capacitor 2 will be determined only by resistor 1.

When the potential is exceeded; the base of transistor 3 (due to the charge of capacitor 2) 1 over the emitter potential of the same transistor, through its base-ammitter junction, the unlocking current will flow, and transistor 3 will go from the cut-off zone to the active zone mode (partially open).

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Since the collector current of transistor 3 is the base current of transistor 7, the latter passes already close to the border of the saturation region. Due to this, the potential of the PA facing of the capacitor 2 connected to the collector of transistor 7 will change and be positive) (until that time it was negative due to the supply voltage). The capacitor will be forced to unload through the base-emitter junction of transistor 3, which will lead to an avalanche-like opening of transistors 3.7 and the formation of a steep leading edge on sh 8, (see Fig. 2a).

Starting from the moment of time {:, on the bus 8 of the generator there is a positive potential (Fig. 26), under the heading & through which resistors 9 and 11 will charge: capacitor 10 to voltage UIQ (Fig. 2c). The value of the resistor 11 in comparison with the value of the resistor 9 is small and the constant charging time of the capacitor 1O will be determined by the resistor 9,

If the potential of the base of the transistor 12 is alarming (due to the charge of the capacitor U) over the emitter potential of the same transistor through its base-emitter ne; the transistor will flow a unlocking current, which at. leads to avalanche-like; opening transistors 12, 13, i.e. all the processes are repeated as in the first relaxation generator. ditsd-to. maximum threshold; urr Щn sh.,., i where; 11.2, respectively The voltage of transistors b2 0 13, .Geipn tr of charge of capacitor 1b is greater than t of discharge of capacitor 2-plus ID recharge and capacitor 2. In the other case, the level of recharge of the divider 2 is determined for the warmth of the pulse.

Just because the charge current through the shock absorber and the capacitor 2 flows through the base-emitter junction of the trazistor 3, then all this time the transistors of the first cell of the generator: are in a vyshivy state

As the trazistor 13 opens so much, its collector current opens the key transistor 14, which also opens into the transistor 15. The open trazistor 15 connects the trazistor 7 base to the ground and the transistor 7 closes. The re-coupled capacitor 2 begins to first discharge through resistor I and then charge through the same resistor to the threshold level

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in, equal to the emitter voltage of the transistor 3.

Then all the processes are repeated.

The capacitor 1.0 is discharged in the interpipe pulses.

The duration of the generated pulses of the frequency limit is determined as well as the pause between the pulses of only a constant charge time of the capacitors 2 to 1O through constant resistors 1.9. As a result, maximum stability is achieved for the duration of both the output pulses and the pauses between them.

For comparison (in Fig. 2d), output pulses (bus 26) are shown, the strength of which is unstable, since they are formed during the discharge and recharge times of the capacitor 10 through the input resistance of the transistor 12, which varies for many reasons.

Claims (2)

1. Author's certificate of the USSR N9 22737O, cl. H 03 K 3 / C2, U966, 2. USSR author's certificate number 362423, cl. N OZ K 3 / O2, 197O. Sria i to V