SU531257A1 - Controlled Multivibrator - Google Patents

Description

(54) CONTROLLED MULTI VIBRATOR

one

The invention relates to software, measuring and computing technology.

A known controlled multivibrator, made on transistors with capacitive collector-base connections, contains a power supply voltage divider and a control unit.

However, in the known multivibrator, the equality of the first and subsequent periods is not ensured after their transfer from the inhibited mode to the self-oscillatory one.

The aim of the invention is to obtain equality of the first and subsequent periods of oscillation.

For this, a controlled multivibrator, made on transistors with capacitive collector-base connections, contains a power supply voltage divider, a control unit, a coupling capacitor connected to one collector of the original open transistor of the multivibrator, another terminal of the closed transistor of the multivibrator through the closing contacts, and to the middle one, the divider voltage is -1

| Power supply source - through the break contacts of the control unit switch.

The drawing shows an electrical configuration of the multivibrator.

The controlled multivibrator contains an initially closed. Transistor 1 and an initially open transistor 2, coupling capacitors 3 and 4, a control unit 5, resistors 6 and 7 of the power supply voltage divider, stabilizing emitter followers 8-10 in the charge and discharge circuit. yes coupling capacitors 3 and 4 and output terminal I.

Multivibrator works as follows.

In the initial state, transistor 1 is closed, transistor 2 is open. The capacitor plate 3, connected to block 5, has a potential equal to the отп ни l voltage. transistor 1. This value is set by the voltage divider at resistors 6 and 7. At the same time, the current set by the stabilizing emitter follower 9 flows through the collector-emitter junction of the open transistor 2, the current of the emitter follower 10 passes through the base-emitter junction of transistor 2 and current emitter repeater 8 flows through the resistor 7.

When switching contacts of the block 5 facing

the capacitor 3 is connected to the base circuit

; transistor 1 and a voltage is applied to its input

.11 Qjf In this case, transistor 1 opens, and tran Transistor 2 closes.

The capacitor 4, which is charged to this day before the supply voltage E JJ, is discharged by the current specified by the emitter follower 10, and the capacitor 3 is charged by the current set by the emitter repeater 9, while the charge current of the capacitor 3 flows through the base-emitter junction of the open transistor 1. During the discharge of the capacitor 4 and the charge of the capacitor 3, the first part of the first period is formed. When the capacitor 4 is completely discharged and the voltage across its transistor 2 connected to the input of transistor 2 is equal to U, transistor 2 opens and transistor 1 closes. This moment defines the first part of the first period. Then, the formation of the second part of the period begins, which is determined by the process of discharge of the capacitor 3. In this case, the discharge current of the capacitor 3 flows through the diode 12 and the collector-emitter junction of the open transistor 2.

The value of the second part of the first period will be determined by the time required for the full discharge of capacitor 3, plus the time to recharge it in the opposite direction until the voltage Ug is reached at the input of transistor 1.

When the voltage of the capacitor 3 at the input of the transistor 1 is equal to Ujj j, the transistor opens and the transistor 2 closes and the first part of the second period forms.

The processes occurring during the formation of the second and subsequent periods are repeated. To the moment of the beginning of the formation of the second period, the capacitor 4 has time to be charged before the voltage

since its constant

of time

food

P

less time

charge essentially capacitor 3.

The first and subsequent periods of the multivibra j oscillator are equal. This is because

in the inhibited mode, the initial capacitor 3 is supplied with such an initial charge, which appears in the auto-oscillating mode at the moment of unlocking the transistor 1, and the capacitor 4 is always charged before the source starts its discharge

The switch Ip, by switching the contacts of the switch b in block 5 to the initial state, the control multivibrator is switched to the retarded mode.

Claims (1)

Invention Formula A controlled multivibrator, made on transistors with capacitive collector-base connections, contains a power supply voltage divider, a controllable unit, characterized in that, in order to obtain equality of the first and subsequent periods of robbing, a communication capacitor connected to the collector of the initially open transistor of the multivibrator, is connected by another output to the base of the originally closed transmultivibrator the multivibrator resistors through the make contacts, and to the middle section of the voltage divider, via the break contacts of the control unit switch.