CN203561373U - Measuring circuit of capacitive transducer - Google Patents

Measuring circuit of capacitive transducer Download PDF

Info

Publication number
CN203561373U
CN203561373U CN201320736619.XU CN201320736619U CN203561373U CN 203561373 U CN203561373 U CN 203561373U CN 201320736619 U CN201320736619 U CN 201320736619U CN 203561373 U CN203561373 U CN 203561373U
Authority
CN
China
Prior art keywords
operational amplifier
input end
resistance
capacitive transducer
model
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN201320736619.XU
Other languages
Chinese (zh)
Inventor
黄友华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chengdu Hongshan Technology Co Ltd
Original Assignee
Chengdu Hongshan Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chengdu Hongshan Technology Co Ltd filed Critical Chengdu Hongshan Technology Co Ltd
Priority to CN201320736619.XU priority Critical patent/CN203561373U/en
Application granted granted Critical
Publication of CN203561373U publication Critical patent/CN203561373U/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Landscapes

  • Measurement Of Resistance Or Impedance (AREA)

Abstract

The utility model discloses the measuring circuit of a capacitive transducer, which comprises a first operational amplifier and a second operational amplifier. A resistor R1 is connected between the non-inverted input end and the output end of the first operational amplifier. A resistor R2 is connected between the inverted output end and the input end of the first operational amplifier. The inverted output end of the first operational amplifier is grounded through a resistor R7. The non-inverted input end of the first operational amplifier is connected with a capacitor C1 and is also connected with the inverted input end of the second operational amplifier. The non-inverted input end of the second operational amplifier is grounded through a resistor R3. A resistor R4 is connected between the inverted input end and the output end of the second operational amplifier. The output end of the second operational amplifier is connected with a zero-crossing comparison circuit. The measuring circuit of the capacitive transducer is high in data measuring accuracy and meets the high measurement requirements in multiple fields.

Description

The metering circuit of capacitive transducer
Technical field
The utility model relates to a kind of metering circuit, relates in particular a kind of metering circuit of capacitive transducer.
Background technology
Capacitive transducer have that measurement range is large, highly sensitive, the advantage such as dynamic response is fast, good stability, especially very little in measurement mechanical moment and do not need to carry out any type of pre-conversion, therefore it has application in a lot of fields, especially in the non-contact measurement field of the physical quantitys such as displacement, pressure or acceleration.The metering circuit of capacitive transducer is mainly the change of electric capacity to be converted to the variation of voltage or electric current.In a lot of fields, in the measuring process of degree speed, acceleration, to the measuring accuracy of data require high.
Utility model content
The utility model provides a kind of metering circuit of capacitive transducer, and the measuring accuracy of its data is high, meets the measurement needs of multi-field high request.
For solving above-mentioned technical matters, the utility model by the following technical solutions:
The metering circuit of capacitive transducer, it comprises the first operational amplifier and the second operational amplifier, between the in-phase input end of the first described operational amplifier and output terminal, be connected with resistance R 1, between the reversed-phase output of the first operational amplifier and output terminal, be connected with resistance R 2, the reversed-phase output of the first operational amplifier is connected to the ground by resistance R 7, on the in-phase input end of the first described operational amplifier, be connected with capacitor C 1, the in-phase input end of the first described operational amplifier is connected on the inverting input of the second operational amplifier, the in-phase input end of the second described operational amplifier is connected to the ground by resistance R 3, between the inverting input of the second operational amplifier and output terminal, be connected with resistance R 4, on the output terminal of the second operational amplifier, be connected with zero passage comparator circuit.
Further technical scheme is:
As preferably, comparator circuit comprises the 3rd operational amplifier, the in-phase input end ground connection of the 3rd described operational amplifier, the reverse input end of the 3rd operational amplifier is connected to by resistance R 5 on the output terminal of the second operational amplifier, and the inverting input of the 3rd operational amplifier is connected to the ground by resistance R 6.
Further, the model of operational amplifier is AD818.
Further, the model of the 3rd described operational amplifier is LT1719.
Compared with prior art, the beneficial effects of the utility model are:
The utility model utilization be take the multivibrator that the first operational amplifier is core the volume change of electric capacity is carried out to converted measurement, and the second operational amplifier carries out negative sense feedback to electric capacity, and utilize zero passage comparator circuit to process capacitance variations value, can effectively improve the measuring accuracy to capacitance variations, make it be applicable to multi-field high-precision measurement demand.
Accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.
Fig. 1 is circuit theory diagrams of the present utility model.
Embodiment
Below in conjunction with accompanying drawing, the utility model is further described.Embodiment of the present utility model includes but not limited to the following example.
[embodiment]
The metering circuit of capacitive transducer as shown in Figure 1, it comprises the first operational amplifier and the second operational amplifier, between the in-phase input end of the first described operational amplifier and output terminal, be connected with resistance R 1, between the reversed-phase output of the first operational amplifier and output terminal, be connected with resistance R 2, the reversed-phase output of the first operational amplifier is connected to the ground by resistance R 7, on the in-phase input end of the first described operational amplifier, be connected with capacitor C 1, the in-phase input end of the first described operational amplifier is connected on the inverting input of the second operational amplifier, the in-phase input end of the second described operational amplifier is connected to the ground by resistance R 3, between the inverting input of the second operational amplifier and output terminal, be connected with resistance R 4, on the output terminal of the second operational amplifier, be connected with zero passage comparator circuit.In the utility model, utilize the first operational amplifier to form multivibrator, the variation of capacitance is converted into the variation of output frequency, it can make to export before and after the pulse of square wave more precipitous.Operational amplifier and peripheral circuit carry out negative sense compensation to the capacity of electric capacity, when compensation power down, hold after the capacity of body, and output frequency will have the rising of certain amplitude.Zero passage comparator circuit can make the output pulse of the first operational amplifier and the level of follow-up frequency senser compatibility, and the conversion between its applicable bidirectional analog signal and single supply logic level, also makes circuit more succinct.Utilize two operational amplifiers and zero passage comparator circuit to measure capacitor's capacity, the accuracy of detection that it is changed capacitor's capacity is high, makes it be applicable to multi-field high-precision measurement demand.
Described zero passage comparator circuit comprises the 3rd operational amplifier, the in-phase input end ground connection of the 3rd described operational amplifier, the reverse input end of the 3rd operational amplifier is connected to by resistance R 5 on the output terminal of the second operational amplifier, and the inverting input of the 3rd operational amplifier is connected to the ground by resistance R 6.Zero passage comparator circuit mainly consists of a pre-computation amplifier, and it is simple in structure, can simplify circuit and connect.
In order to reduce measuring error, improve accuracy of detection, the model of the first described operational amplifier is AD818.AD818 is high precision, low noise operational amplifier, and the representative value of its common mode input capacitance is only 1.5Pf, can reduce the measuring error of operational amplifier when with sensor body Capacitance parallel connection.
In order to improve further raising accuracy of detection, the model of the 3rd described operational amplifier is LT1719.LT1719 is low pressure, dual power supply comparer at a high speed, the dual power supply of chip input end and the single supply of output terminal arrange separately at chip internal, therefore be well suited for the conversion of casing between simulating signal and single supply logic level, make circuit structure simple, can reduce measuring error.
Be as mentioned above embodiment of the present utility model.The utility model is not limited to above-mentioned embodiment, and anyone should learn the structural change of making under enlightenment of the present utility model, every with the utlity model has identical or close technical scheme, within all falling into protection domain of the present utility model.

Claims (4)

1. the metering circuit of capacitive transducer, it is characterized in that: it comprises the first operational amplifier and the second operational amplifier, between the in-phase input end of the first described operational amplifier and output terminal, be connected with resistance R 1, between the reversed-phase output of the first operational amplifier and output terminal, be connected with resistance R 2, the reversed-phase output of the first operational amplifier is connected to the ground by resistance R 7, on the in-phase input end of the first described operational amplifier, be connected with capacitor C 1, the in-phase input end of the first described operational amplifier is connected on the inverting input of the second operational amplifier, the in-phase input end of the second described operational amplifier is connected to the ground by resistance R 3, between the inverting input of the second operational amplifier and output terminal, be connected with resistance R 4, on the output terminal of the second operational amplifier, be connected with zero passage comparator circuit.
2. the metering circuit of capacitive transducer according to claim 1, it is characterized in that: described zero passage comparator circuit comprises the 3rd operational amplifier, the in-phase input end ground connection of the 3rd described operational amplifier, the reverse input end of the 3rd operational amplifier is connected to by resistance R 5 on the output terminal of the second operational amplifier, and the inverting input of the 3rd operational amplifier is connected to the ground by resistance R 6.
3. the metering circuit of capacitive transducer according to claim 1 and 2, is characterized in that: the model of the first described operational amplifier is AD818.
4. the metering circuit of capacitive transducer according to claim 2, is characterized in that: the model of the 3rd described operational amplifier is LT1719.
CN201320736619.XU 2013-11-21 2013-11-21 Measuring circuit of capacitive transducer Expired - Fee Related CN203561373U (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201320736619.XU CN203561373U (en) 2013-11-21 2013-11-21 Measuring circuit of capacitive transducer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201320736619.XU CN203561373U (en) 2013-11-21 2013-11-21 Measuring circuit of capacitive transducer

Publications (1)

Publication Number Publication Date
CN203561373U true CN203561373U (en) 2014-04-23

Family

ID=50511088

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201320736619.XU Expired - Fee Related CN203561373U (en) 2013-11-21 2013-11-21 Measuring circuit of capacitive transducer

Country Status (1)

Country Link
CN (1) CN203561373U (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103743420A (en) * 2013-11-21 2014-04-23 成都市宏山科技有限公司 Measuring circuit for capacitance sensor
CN104316087A (en) * 2014-09-30 2015-01-28 广东合微集成电路技术有限公司 Measuring circuit of capacitive sensor

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103743420A (en) * 2013-11-21 2014-04-23 成都市宏山科技有限公司 Measuring circuit for capacitance sensor
CN104316087A (en) * 2014-09-30 2015-01-28 广东合微集成电路技术有限公司 Measuring circuit of capacitive sensor

Similar Documents

Publication Publication Date Title
CN202928716U (en) High precision intelligent temperature measurement circuit
CN103684408A (en) Capacitance-type sensor interface circuit
CN203561373U (en) Measuring circuit of capacitive transducer
CN103293566B (en) Signal detection circuit of atmospheric ozone sonde
CN203376374U (en) Voltage sensing module based on photoelectric couplers
CN102830262B (en) Alternating current detection circuit based on bidirectional optocoupler
CN206670819U (en) High-precision charging gun temperature sensing circuit
CN104655236A (en) Liquid level measuring system
CN202853834U (en) Pressure measuring device with temperature drift compensation
CN103743420A (en) Measuring circuit for capacitance sensor
CN203587243U (en) Temperature acquiring and processing circuit for electric-bag composite dust collector
CN204559519U (en) The signal detection amplifying circuit of pressure sensor
CN202815064U (en) Sensor for detecting voltage of solar cell assembly
CN203519728U (en) Differential capacitance type sensor detection circuit
CN203177865U (en) Measuring and controlling circuit of capacitance sensor
CN102854367A (en) Sensor used for detecting voltages of solar cell module
CN205958139U (en) Temperature transmitter that accuracy is high
CN203233395U (en) Port multiplexing interface circuit for capacitance-type sensor
CN207501859U (en) High-precision strain measurement system
CN203216569U (en) High-precision underground water level monitoring device
CN103438911B (en) LC resonant transducer reading system under fixed pattern frequently and method
CN203883811U (en) Analog-to-digital converting module of transformer station gas concentration detecting system
CN203364757U (en) Tiny inclination angle detection apparatus
CN203881355U (en) Circuit for converting detected signal in transformer station gas concentration detection system
CN105466609A (en) Capacitance-type micro-differential pressure smart transmitter

Legal Events

Date Code Title Description
C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20140423

Termination date: 20141121

EXPY Termination of patent right or utility model