SU1686577A1 - Device ofr protection of load against change of input voltage - Google Patents

Abstract

This invention relates to automatic regulation and can be applied in emergency protection devices. The purpose of the invention is to optimize the operation of the device. As the input voltage rises to the trigger threshold, transistor 7 closes. Threshold element 3 is punctured. The device becomes self-locking. When the supply voltage is turned on, transistor 7 opens. The output voltage is low and the feedback is turned off. The device switches to self-blocking. The device is removed from the lock by briefly pressing button 4. 1 sludge. J

Description

QU,

The invention relates to automatic regulation and can be applied in various technical fields, for example, in emergency protection devices.

The purpose of the invention is to optimize the operation of the device.

The drawing shows a schematic diagram of the device.

The circuit contains an input voltage source 1, a variable resistor 2. a threshold element (a two-channel zener diode) 3, a lock-off button 4, a Schmidt trigger 5, an output switch consisting of a resistor 6 and a transistor 7

The device works as follows.

At the moment of switching on the supply voltage, the instantaneous value of the voltage on the non-inverting input of the trigger is equal to

UH UO,

while at its inverting input voltage is determined by the expression

U,

 (Ui-UBx-UcQ-Rix

Ri + Rs

+ UB

where UCT is the breakdown voltage of a two-anode zener diode;

RIX is the resistance part of the variable resistor 2.

Depending on the position of the slider of the variable resistor 2, the device is either switched to self-locking when turned on, with Deux having a high level (two-anode Zener diode), threshold element 3 is in a conducting state, or into operation mode and 1) Output has a low level, for example A threshold element 3 (a two-anode zener diode) is not enough to break it down.

In the first case, the device is switched to the operating mode by briefly pressing the lock button 4. When the button contact is opened, the positive feedback is turned off, and transistor 7 opens.

When the button is closed, the reverse of the positive connection remains in the disconnected state, since the output voltage

has a low level and the voltage at the threshold element 3 (two-anode zener diode) is lower than its breakdown voltage.

Increasing the input voltage and

when the threshold voltage of the trigger 5 is reached, the trigger closes the transistor 7, the output voltage takes a high level, the two-anode Zener diode 3 pierces, the reverse positive is turned on, the device becomes self-blocking.

In the second case, when the power is turned on, the transistor 7 opens, the output voltage takes a low

Level 5, the voltage at the two-anode zener diode 3 below its breakdown voltage, is inversely connected to the positive link. The transition of the device to self-locking is similar to the first case.

0 The device is unlocked by briefly pressing the lock off button 4.

Using this technical solution allows to optimize the mode

5 of installations where it is used, which ensures economical use of electrical equipment and energy savings

Claims (1)

Invention Formula 0 A device for protecting the load against a change in input voltage containing a Schmidt trigger, a threshold element and a resistor, characterized in that, in order to optimize the operation of the device, 5, an output switch on the transistor, a variable resistor, and a lock-off button are entered, the inverting trigger input is connected to the middle terminal of the variable resistor, the first The 0 pin of which is connected to the terminal for connection to the input voltage source, and the second pin through the threshold element - to the first pin of the lockout off button, the second pin of which is single with the collector of the output key transistor, the base of which is connected to the trigger output via a resistor the output key transistor is connected to a terminal for connecting to a common bus. 0