SU1429194A1 - Device for switching on a relay with low supply voltage - Google Patents

Abstract

The invention relates to electrical engineering and can be used in switching devices. The purpose of the invention5 is to enhance operational capabilities. When applied through the resistor 2 to the base of the transistor 1 of the first control pulse, the transistor 1 opens. A negative voltage is applied to the cathode of the thyristor 7. Thyristor 7 opens. A double voltage is applied to the winding of the relay 5. The device is disconnected by applying a second control pulse. In this case, the thyristor 7 is shunted by a transistor 1 and a diode 4. 1 sludge.

Description

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- The invention relates to electrical engineering and can be used by switching devices.

The aim of the invention is to expand the operational capabilities of the device by pulsing the on-off control of the relay on one input.

1 The drawing is a schematic diagram of a device for turning on a relay when the supply voltage is low.

The device contains a transistor 1, the base of which is through the first resistor

2 is connected to the input of the device, the emitter is connected to the common bus j; the collector is connected to the first terminal of the electrolytic capacitor 3 and through the diode | 4 to the first terminal of the connection of the winding of the relay 5, the second terminal of which is connected to the power bus, the second terminal

I capacitor 3 through diode 6 is connected 1C by a common bus, thyristor 7 and resistor 8, and the thyristor 7 anode is connected to the first output terminal of the winding of relay 5, the cathode is connected to the junction point of capacitor 3 and diode 6, the control electrode through resistor 9 is connected to common bus, and the resistor 8 is connected between the collector of the transistor 1 and the common bus.

The device works as follows.

In the initial state, a zero voltage is applied to the input terminals (for example, from TTL logic). The transistor 1 is closed, and the capacitor 3 is charged through the winding of the relay 5 and the diodes 4 and 6 almost to the supply voltage. Thyristor 7 is closed, i.e. the current through the winding of the relay 5 does not leak. When the first positive voltage pulse arrives, transistor 1 opens, switching the positive side of capacitor 3 to the common bus. At the same time, a negative voltage is applied to the cathode of the thyristor 7. The thyristor 7 is opened, so that the control electrode is connected via resistor 9 to a common bus. Thus, almost double the supply voltage is applied to the winding of the relay 5. Relay 5 is activated, capacitor 3 is discharged, and relay 5 remains in the on state due to the flow of current through the open thyristor 7 and diode 6. Transistor 1 is closed at the same time. Duration

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the control pulse must be no less than the on time of the relay 5.. When the second positive voltage pulse arrives, the transistor I opens and the thyristor 7 shunts with diode 4 and the open transistor 1, which puts it in the closed state. And since the capacitor 3 in this case is in a discharged state (due to resistor 8), it does not affect the operation of the device. The duration of the closing pulse must be no less than the turn-off time of the thyristor 7. Subsequently, transistor 1 and thyristor 7 are in the closed state, the capacitor 3 is charged almost to the supply voltage. The device is ready to turn on the relay 5.

Thus, in the proposed device, pulsed control of switching on and off of the relay on one input is carried out, which expands its operational capabilities.

Claims (1)

Invention Formula A device to turn on the relay at low voltage supply, containing terminals for connecting the relay coil, two key elements, one of which used a transistor, two diodes, two resistors, an electrolytic capacitor, and the dd terminals of the power supply, and the base of the transistor the resistor is connected to the input of the device, the emitter of the transistor is connected to the output to connect the negative pole of the power source, and the collector to the first output of the electrolytic capacitor and the cathode the first diode, the second electrolytic capacitor output is connected via a second diode to the output for connecting the negative pole of the power supply, the second key element is connected between the connection point of the second output of the electrolytic capacitor and the second diode and the first operating device for connecting the relay coil, the second output for connecting which is connected to the output for connecting the positive pole of the power source, the control electrode of the second key element is connected via a second resistor to the output terminal yuche31429194 neither the negative pole of the source thyristor, and the anode of the first power supply diode, is differently connected to the first output for the purpose that, in order to expand the operation of the relay coil, the third resistor capability is connected between the collector and the emitter of the second key element is selected transistor.