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A capacitance signal measurement circuit and measurement method

A signal measurement and capacitance technology, applied in capacitance measurement, measurement of electrical variables, measurement of resistance/reaction/impedance, etc. Effect

Active Publication Date: 2021-04-06
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, most of the current measurement methods are difficult to measure a larger range on the basis of ensuring a higher measurement resolution

Method used

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  • A capacitance signal measurement circuit and measurement method
  • A capacitance signal measurement circuit and measurement method
  • A capacitance signal measurement circuit and measurement method

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Embodiment 1

[0026] This embodiment discloses a capacitance signal measurement circuit, such as figure 1 As shown, including the measured capacitor C1, the reference capacitor C2, the controlled switch S1, the controlled switch S2, the controlled switch S3, the operational amplifier U1, the operational amplifier U2 and the adjustable voltage source, the power supply Vcc is connected to the Node A, one end of the measured capacitor C1 is connected to node A through a resistor R1, and the other end is grounded, one end of the controlled switch S2 is connected to node A, and the other end is grounded through a resistor R2, one end of the controlled switch S3 is connected to node A, and the other end is connected to To the non-inverting input of operational amplifier U1, the reference capacitor C2 is connected between the non-inverting input of operational amplifier U1 and ground; the adjustable voltage source is connected to node B through resistor R7, and node B is connected to the negative p...

Embodiment 2

[0032] This embodiment discloses a capacitance signal measurement method, the measurement method is based on such as figure 2As shown in the measurement system, the measurement system includes a microcontroller and a capacitance signal measurement circuit, and the capacitance signal measurement circuit is exactly the capacitance signal measurement circuit described in Embodiment 1. During work, the microcontroller supplies the adjustable voltage source, the subject The control switch S1, the controlled switch S2, and the controlled switch S3 send control signals, and adjust the control signals according to the output voltages Vout1, Vout2 of the operational amplifiers U1, U2, thereby realizing the measurement of the capacitance signal.

[0033] The concrete steps of this method are:

[0034] S01), discharge the measured capacitor C1 and the reference capacitor C2, so that the positive input terminal voltage Vin of the operational amplifier U1 is zero, the specific process is:...

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Abstract

The invention discloses a capacitance signal measurement circuit and measurement method, including a measured capacitance C1, a reference capacitance C2, a controlled switch S1, a controlled switch S2, a controlled switch S3, an operational amplifier U1, an operational amplifier U2 and an adjustable voltage source , to realize capacitance signal measurement by repeatedly charging the measured capacitance. The present invention can achieve higher measurement resolution, and can adjust the capacitance measurement range through the adjustable voltage source to realize a larger range of capacitance value measurement, eliminate the influence of parasitic capacitance by controlling the output voltage of the voltage regulator, and increase the measurement range. It has great application value for capacitive sensors with large parasitic capacitance.

Description

technical field [0001] The invention relates to weak signal measurement technology, in particular to the measurement of weak capacitance changes, and relates to a capacitance signal measurement circuit and measurement method, which can be used for capacitance sensor measurement. Background technique [0002] With the development of microelectronics and sensor technology, capacitive sensors are widely used in biopharmaceuticals, medical equipment, industrial control and other fields. Capacitive sensors generally have the advantages of simple structure, high precision, reliable operation, fast dynamic response, and non-contact measurement. Features. [0003] Capacitive sensors are getting smaller and smaller, resulting in very small changes in capacitance. Results The effect of the stray capacitance of the capacitive sensor cable is very significant. And the stray capacitance will change with the influence of many factors such as temperature, structure, position, internal an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R27/26G01D5/24
CPCG01D5/24G01R27/2605
Inventor 王冬雪王中华房文静李猛李荣伟
Owner UNIV OF JINAN