SU1734027A1 - Device for voltage measuring - Google Patents

Abstract

The invention relates to electrical measuring equipment and can be used in control devices. The purpose of the invention — improving measurement accuracy — is achieved by introducing feedback through the optical channel and using capacitors 7.8. The device also contains an amplifier 1, optopara 2.3, resistors 4,5,6. 1 il.

Description

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The invention relates to electrical measuring equipment and can be used in control devices.

The purpose of the invention is to improve the accuracy of voltage measurement.

The drawing shows a functional diagram of the device.

The device for measuring voltage consists of amplifier 1, optocouples 2.3, resistors 4, 5, 6, 6, capacitors 7, 8, LED 9, transistors 10, 11, LED 12.

The device works as follows.

The measured voltage is applied to the non-inverting input of amplifier 1. With respect to the first common bus, this voltage is positive and constant. In this case, the potential at the inverting input of amplifier 1 is equal to the potential of the first common bus. As a result, the output of amplifier 1 is set to a positive voltage. Current begins to flow through the limiting resistor 5 and the LED 9. The transistor 10 opens and a current appears in the circuit: the second power input, the LED 12, the transistor 10, the resistor 6, the second common bus. As a result, the transistor 11 opens and a current in the circuit appears: the first power input, the transistor 11, the second resistor 4, the first common bus. On the resistor 6, the output voltage of the device is isolated, and on the resistor 4, the negative feedback voltage. At the same time, capacitors 7.8 are charged, which prevent the device from going into generation mode. Under the action of feedback voltage, a linear transmission mode of the input signal is established. In addition, stabilization of the regime occurs. With the influence of external factors, the current through the transistor 10 increases at a constant input voltage. Then, the currents flowing through the LED 12 and the transistor 11 also increase. Is increasing

feedback voltage value. As a result, the current through the LED 9 is reduced, and the parameters of the transistor 10 are returned to the starting point of the characteristic. Similar processes occur when the current flowing through any element of optocoupler 2 or 3 changes. The instability of the power supply sources is also compensated for by negative feedback. An increase in measurement accuracy is achieved by increasing the linearity of the device and the stability of the characteristics during temperature changes.

Claims (1)

Claims A device for measuring voltage, containing an amplifier, two optocouplers, three resistors, the first output of the second resistor is connected to the inverting input of the amplifier, the output of which is connected to the first output of the third resistor, characterized in that in order to improve the measurement accuracy, two capacitors , the emitter of the transistor of the second optocoupler is connected to the first output of the second resistor and the first output of the second capacitor, the second output of the third resistor is connected to the anode of the LED of the first optocoupler, the second output d the second capacitor, the second output of the first resistor, the cathode of the LED of the first optocoupler is connected to the first common bus; the output of the first resistor, the second output of the first capacitor is connected to the second common bus, the non-inverting amplifier input is the device input, the collector of the transistor is the second opto-element ry and the anode of the LED connected to the second optocoupler unit power rails.