SU563708A1 - Multivibrator - Google Patents

Description

one

The invention relates to radio metering and pulse technique and can be used as a master multivibrator when building a pulse generator.

An I. quest multivibrator containing a Schmidt trigger on a pn-transistor, the input of which is connected to the capacitor plate, the other of which is connected to the OB1, its bus, charge and discharge ycTpoii 1.

However, this multivibrator has insufficient frequency control diaiazon, limited by the input base current} of the south of the Schmidt trigger transistor, as well as the insufficient stability of the duration of the generated pulses due to the change of the charging current when the frequency changes.

The purpose of the invention is to expand the range of stepless frequency control and stabilize the duration of the generated pulses.

For this, in the proposed multivibrator, the inputs of a discharge device made in the form of a current switch “and pnp transistors, whose emitters are connected to an adjustable current source on pnp transistors, and a charging device made in the form of a switch The current is connected to the output of a Schmidt trigger, and the outputs are connected to a capacitor.

The drawing shows; is a schematic diagram of the iodo multivibrator circuit.

The multivibrator contains a Schmidt trigger on transistors 1 and 2, a capacitor 3, a charging device on transistors 4 and 5, a discharge device on transistors 6 and 7, an adjustable current source on transistor 8 connected to the emitters of transistors G and 7, and the collectors of transistors 5 and 7, which are the outputs of a charging n discharge device, are combined and connected to the Schmidt trigger input connected to a common nypüy via a capacitor 3, and the Schmidt trigger outputs are connected to the inputs of a charging and discharge device.

Multivibrator works in the same way.

When powered on, the multivibrator is always in unstable

condition.

Suppose that transistor 1 is turned on, and transistor 2 is turned off, then transistor 5 is turned on, and transistor 4 is turned off, transistor 6 is turned on, and transistor 7 is turned off. The capacitor 3 is charged through the transistor 5. As soon as the voltage on the capacitor 3 exceeds the base of the transistor 2, the Schmidt trigger switches regeneratively. With this, transistors 5, 7 are closed, and transistors 4, 6 are opened. The capacitor 3 begins to discharge through transistors 7 and 8.

.3:, t. -vf:. .

 - The mapping on the capacitor 3 begins to decrease, and as soon as the base potential of transistor 1 becomes less than the base potential of transistor 2, the Schmndt trigger switches regeneratively and the circuit is restored to its original state.

When the capacitor 3 is discharged, the base current of the transistor I is absent, which makes it possible to expand the frequency control range with a constant duration of the generated pulses.

Claims (1)

Invention Formula A multivibrator containing a Schmidt trigger on npn transistors, the input of which is connected to a capacitor plate, another plate of which is connected to a common bus, charging and discharging device, characterized in that in order to extend the range of a smooth frequency adjustment n stabilization for 1 pulse of the generated pulses, the discharge device is designed as a current switch on / 5-np transistors, the emitters of which are connected to an adjustable current source of pa-pnp transistors, and the charger is made as a switch current sensor on p-p-transistors, inputs the discharge and charge of the 1st device are connected to the output of the Schmidt trigger, and their outputs are combined and connected to the capacitor. Sources of information taken into account in the examination l.Triese T., Nentwich H- Eine astabile Kippschaltung fur Hz ... 10 MHz. - “Jnternationale Hlectronische Riiiulbcliau, 1965, 19, As G, c. 334--335.