SU138957A1 - Multivibrator - Google Patents

Description

Cathodic coupled multivibrators used to produce bursts of pulses are known. The main disadvantage of such devices is the difficulty of adjusting the pack duration and pulses and the duration of individual pulses.

In the described device, an additional lamp is connected parallel to the lamp of the amplifying stage, the grid circuit of which includes a source of control voltage. An additional lamp performs the same functions as the main lamp, but generates pulses of a different duration. This makes it possible to receive at the output of the multivibrator packs of pulses of variable duration and it is quite simple to adjust the duration of the pack of pulses and the duration of individual pulses.

A schematic diagram of the multivibrator is shown in the drawing.

Positive load voltages of batteries 1, 2, and 3 determine the generation mode. The device can work in the delayed and periodic modes. In the delayed mode, the voltage of the battery 1 must be less than the voltage of the battery 2, which, in turn, is less than the voltage of the battery 3. Diodes 4 and 5 are open, and lamps b and 7 are locked. The capacitor 8 is charged up to the voltage of the difference between the anode power supply and the batteries 5. The capacitor 9 is charged up to the battery voltage. After the trigger pulse, the diodes 4} 5 are closed, and the lamps and 7 open like an avalanche. The capacitor 9 is discharged to the resistance 10, which closes the lamp 6. The capacitor 9 is recharged. The discharge period of the capacitor 9 is determined by the capacitance of the capacitor and the resistance 10. During the recharging of the capacitor 9, the lamp 7 remains open, because the capacitor 8 during the discharge period of the capacitor 9 does not have time to completely discharge to the resistance 11, and discharges only partially . Thus, relaxation oscillations occur, in

the generation of which involves lamps 6 and 7. As the capacitor 8 discharges, the voltage on the grid of the lamp 12 and the a C of the resistance 13 increases. When the voltage on the capacitor 9 at the time of the charge becomes equal to the battery voltage /, the diode 4 will open and shunts capacitor 9. The further discharge of capacitor 8 lasts until the moment when the voltage on resistance 13 becomes equal to the voltage of battery 2. At this moment diode 5 opens and lamp 7 closes like an avalanche. Capacitor 8 is re-charged until the voltage is in the initial state. Thus, the trigger pulse causes a complex oscillation in the device containing a series of pulses. The number of pulses in a series is determined by the time constant of the chain, consisting of a capacitor 9 and a resistance 10, as well as the battery voltage. At constant values of the capacitance of the capacitor 9 and the resistance 10, the number of pulses in a series depends only on the battery voltage /.

Subject invention

A cathode-coupled multivibrator, characterized in that, in order to obtain bursts of pulses and to simplify control of the duration of the packs and the duration of individual pulses parallel to the lamp of the amplifier stage, an additional lamp is connected, the grid circuit of which is connected to the control voltage source.