SU1465793A1 - Device for two-threshold monitoring of power source voltage - Google Patents

Abstract

The invention relates to electrical measuring equipment and allows to simplify the device. Due to the Zener diode 11, the voltage change at the base of the transistor (T) 8 occurs in smaller limits than at the base T 7. Therefore, the increase in the voltage of the power source (PI) reduces the current through the T 8 up to the locking T 10. The decrease of the voltage PI reduces the current through T 7 and locks T 9 at the lower limit of the voltage PI. In this case, the current through the diode of the optocoupler 12 stops and its T goes into a low conductivity state, indicating a malfunction of the IF. The selection of resistor values (P) 5 and 6 establishes the center of the allowable voltage zone PI. The width is adjusted by P2. The required current through the diode of the optocoupler 12 at the nominal voltage of the IC is set by P3. 1 sludge. (L

Description

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The invention relates to electrical measuring equipment and can be used in systems of automatic monitoring and control.

The purpose of the invention is to simplify the device.

The drawing shows a diagram of the device,

The device contains a resistive divider of resistors 1 and 2, two resistors 3,4, a resistive divider of resistors 5, 6 through transistor 7 - 10, a zener diode 11, an optocoupler 12, a first input terminal 13, the second

input terminal 14 and output terminals 15, 16. The emitters of transistors 7 and 8 through a resistor 4 are connected to the input terminal 14. The base of transistor 8 is connected to the output resistive

divider - common point resistors

I 2, the first input divides (w - resistor 2 - connected via a zener diode

I1c second input terminal 14, the second input delitap - resistor 1st first input: terminal 13, to which the emitter of the transistor is also connected

9. The base of the transistor 7 is connected through a resistor 5 to terminal 13 and through a resistor 6 to 1Shema 14, the collector of transistor 10 through a registor 3 and the optocoupler 12 is connected to e; mm 14, its base is connected to the collector of transistor 8, the emitter is connected to the collector of the transistor

The device works as follows.

The device is connected to the power supply of the monitored power source with the polarity of its input terminals. The parameters of resistors and stabilizers are such that if the voltage of the power source is within the specified limits, transistors 7 and 8 are open, providing, due to the flow of current through the bases of transistors 9 and 10, their E: saturation and, consequently, leakage; LED of the optocoupler 12. At the same time, the output condition of the transistor of the optocoupler can be fixed at the output terminals 15, 15, which indicates the normal operation of the power supply.

A change in the voltage of the power supply leads to a change in the voltage of the research institutes at the bases of the transistors 7–8 due to resistive dividers, the formation of a resistor 1 ”m 1, 2 and 5., 6, However, due to the stabilization of the zener diode 11 At the base of the transistor 8 will occur in smaller limits than at the base of the transistor 7. Therefore, increasing the voltage of the power source will lead to a decrease in current through the transistor 8 up to the locking of the transistor 10 at the upper permissible value of the source voltage. Similarly, a decrease in the voltage of the power supply will lead to a decrease in the current through the transistor 7 and to the locking of the transistor 9 at the lower permissible boundary of the source voltage. In either case, the current through the diode of the optocoupler 12 stops and its output transistor goes into a low conductivity state indicating a malfunction of the monitored power source.

By selecting the values of resistors 5, 6, the middle of the allowable voltage zone of the power supply source is knocked down, its width is adjusted by resistor 2. Resistor 3 establishes the required current through the diode of the optocoupler 12 at the rated voltage of the power source

Claims (1)

Invention Formula A device for two-threshold voltage supply voltage control, containing two resistive dividers, the first terminals of which are connected respectively to the first input terminal, the second output of the first resistive divider is connected to the second input terminal to which the emitters of the first and second transistors, the third transistor are connected The emitter of which is connected to the first input terminal, a zener diode, characterized in that, in order to simplify the device, a fourth transistor, a second resistor and an optocoupler are introduced, The outputs of the first and second resistive dividers are connected to the bases of the first and second transistors, the second output of the second resistive divider is connected to the second input terminal via a zener diode, the bases of the third and fourth transistors are connected to the collectors of the first and second transistors, the collector of the third transistor is connected to the emulator of the third transistor. the transistor, the collector of which is the input of the optocoupler, the output of which is connected via a second resistor connected to the output of the device.