SU1322426A1 - Relaxation oscillator - Google Patents

Abstract

The invention relates to square pulse generators and can be used in automation and television devices. The aim of the invention is to extend the range of the generated pulses in the direction of low frequencies. The goal is achieved by the proposed circuit connection of transistors 1, 5, 6 and And, diode 13, capacitor 4 and resistors shown in the drawing. In the generator, in comparison with the prototype, the range of the generated pulses is expanded towards low frequencies, which allows reducing the size and cost of the generator. 1 il. sl oo to to 4 to o5

Description

The invention relates to pulsed technology and can be used as a generator of square pulses in automation devices and television equipment.

The aim of the invention is to extend the range of the generated pulses in the direction of low frequencies.

The drawing shows a diagram of the device.

The relaxation generator contains a current generator of a pnp type transistor 1, the emitter of which is connected to the power supply bus 3 via a variable resistor 2. The collector of the transistor 1 is connected to the first plate of the integrating capacitor 4 and the input of the regenerative switch on the transistors 5 and 6, included according to the equivalent circuit of a two-base diode. The output of the regenerative key is connected to the output terminal 7 and the voltage divider on the series-connected resistors 8-10 connected between the power bus 3 and the common bus. To the point of connection of resistors 9 and 10 is connected to the base of a key transistor 11 of a pn-type, the emitter of which is connected to the busbar, its bus, and the collector - to the second output bus 12, through a series-connected diode 13 and resistor 14 to the bus 3 power supply and through the voltage divider on the resistors 15 and 16c by the base of the current generator transistor 1. A second plate of the integrated capacitor 4 is connected to the connection point of the resistor 14 and the anode of the diode 13.

Relaxation generator works as follows.

When power is applied to bus 3, transistors 1 and 11 are open, and transistors 5 and 6 are locked. The capacitor 4 begins to charge the collector current of transistor 1 through diode 13, the open collector junction of the emitter of transistor 11. When the voltage on the basis of this transistor reaches the value specified by the voltage divider on the resistors 8-10, the transistors 5 and 6 of the regenerative switch open like an avalanche. The collector-emitter junction of transistor 6 shunts the divider across resistors 9 and 10, therefore, transistor 11 is locked, simultaneously locking transistor 1. The charging current of capacitor 4 stops. The capacitor 4 is recharged by the current flowing from the power supply bus 3 through the resistor 14 and the open transistors 5 and 6, so that the voltage on the second plate of the capacitor 4 becomes equal to the positive voltage on the power supply bus 3. As the recharging of the capacitor 4 is completed, the current through the transistors 5. And 6 decreases to zero and they lock up like an avalanche and the transistors 11 and 1 open. On the output bus 12 ends form0

output of a rectangular output pulse of positive polarity. The positively charged second capacitor plate 4 is grounded through diode 13 and the open collector-emitter junction of transistor 11, therefore, the voltage across the first plate of capacitor 4 and emitter of transistor 5 becomes negative.

The transistor 1 current again charges capacitor 4. A pause between the pulses is formed until the voltage on the capacitor changes from a negative voltage equal to the supply voltage to a positive voltage given by the voltage divider on 8-10 when the regenerative key on transistors 5 and 6 opens again and the next positive output pulse is formed on the output bus 12, and a negative pulse of smaller amplitude is formed on the output terminal 7.

0 A diode 13 prevents negative voltage applied to the collector of transistor 11 that occurs in the initial stage of the formation of the output pulse when the positive first charge is positive.

C of capacitor 4 is grounded through transistors 5 and 6, and the potential on its second plate becomes negative.

Since, in the proposed generator, the period between pulses is determined by the recharging time of the capacitor 4 from a negative voltage equal to the voltage on the supply bus 3 to a positive voltage on the divider of resistors 8-10, which is always less than the supply voltage then the period between pulses increases by 2 times over and over with the same capacitor capacitance and the collector current of transistor 1.

Thus, the invention makes it possible to extend the range of the generated pulses towards the lower frequencies or to obtain the same pulse repetition frequency with a smaller value of the capacitance of the time - driving capacitor, which makes it possible to reduce the size and cost of the generator.

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Claims (1)

Invention Formula A relaxation generator containing a current source at a transistor, the collector of which is connected to one plate of an integrating capacitor and the input of a regenerative key on two transistors connected in the equivalent of a two-base diode, the output of which through a resistor is connected to the power bus, a resistive voltage divider connected between regenerative key output and common bus key transistor, the base of which is connected to the midpoint of the resistive divider, and the collector through a resistor connected to the base of the transistor current source. characterized in that, in order to expand through a series-connected diode and rhenium range of generated impulses, the vpistor and their connection point are connected to the low-frequency side, the collector is transissed to the second plate of the integrated capacitor key connected to the sator power supply bus.