CN103048546A - Input circuit for measuring liquid electricity conductivity - Google Patents
Input circuit for measuring liquid electricity conductivity Download PDFInfo
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- CN103048546A CN103048546A CN2012105478237A CN201210547823A CN103048546A CN 103048546 A CN103048546 A CN 103048546A CN 2012105478237 A CN2012105478237 A CN 2012105478237A CN 201210547823 A CN201210547823 A CN 201210547823A CN 103048546 A CN103048546 A CN 103048546A
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- circuit
- input circuit
- operational amplifier
- electricity conductivity
- input end
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- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Abstract
The invention discloses an input circuit for measuring liquid electricity conductivity. The input circuit comprises an operational amplifier, wherein an in-phase input end of the operational amplifier is connected with a sine-wave oscillator, an out-of-phase input end of the operational amplifier is connected with an electricity conductivity measuring electrode, and a resistor is connected between an operational amplifying output end and the out-of-phase input end in a bridging way. The input circuit disclosed by the invention has the benefits that the circuit is simple, cheap and easy to realize, and a linear relationship exists between the output voltage signal of the circuit and a to-be-measured electricity conductivity value; and as long as the output voltage signal of the circuit is sent to sequent rectifying, filtering, amplifying, A/D (Analog-to-Digital) and singlechip circuits, the electricity conductivity value can be accurately and reliably measured.
Description
Technical field
The present invention relates to a kind of input circuit for measuring conductance of liquid, belong to the surveying instrument technical field.
Background technology
Conductance of liquid is as a kind of important electrochemical analysis parameter, and it measures the fields such as chemical industry, metallurgy, biology, medical science, grain, water conservancy, environmental protection, the energy that have been widely used in.Yet the input circuit part of conductivity meter all adopts the principle of balance bridge design at present, but there are the shortcomings such as complex structure, nonlinearity erron in null-type bridge circuit, and there are the shortcomings such as accuracy is low, use inconvenience in the conductivity meter of making thus.
Summary of the invention
Technical matters solved by the invention provides a kind of linearity, simple, accurate, the reliable input circuit that is used for measuring conductance of liquid.
The invention provides a kind of input circuit for measuring conductance of liquid, it is characterized in that this input circuit comprises operational amplifier, the in-phase input end of this operational amplifier connects sine-wave oscillator, anti-phase input termination conductance measurement electrode, resistance is connected across between the output terminal and reverse input end of amplifier.
Described sine-wave oscillator adopts RC bridge-type sine-wave oscillator.
Adopt beneficial effect of the present invention to be: this circuit not only simple, cheap, be easy to realize, and the output voltage signal of this circuit and electric conductivity value to be measured have linear relationship, the output voltage signal of this circuit is delivered to follow-up rectification, filtering, amplification, A/D, single chip circuit, can record accurately and reliably electric conductivity value.
Description of drawings
Fig. 1 is a kind of input circuit figure for measuring conductance of liquid of the present invention.
Embodiment
The present invention is specifically introduced as follows below in conjunction with drawings and Examples:
A kind of input circuit for measuring conductance of liquid described in the invention, comprise operational amplifier U1, and the in-phase input end (+) of operational amplifier U1 connects the RC oscillator, inverting input (-) connects the conductance measurement electrode, resistance is connected across between the output terminal Uo and reverse input end (-) of amplifier, and namely this amplifier forms the in-phase proportion amplifying circuit.
That is, amplifier in-phase end (+) connects the RC oscillator, namely accesses sine wave signal ui, and inverting input (-) connects the conductance measurement electrode, namely accesses measuring resistance Rx to be measured, and its inverse is then led Gx for electricity to be measured, and feedback resistance is Rf, then
Because ui is stable signal, i.e. constant.Can draw according to following formula, Uo and Gx are linear, and the output voltage signal of this circuit is delivered to follow-up rectification, filtering, amplification, A/D, single chip circuit, can record accurately and reliably electric conductivity value.
Below announced the present invention with preferred embodiment, so it is not intended to limiting the invention, all take to be equal to replace or technical scheme that the form of equivalent transformation obtains, all drop within protection scope of the present invention.
Claims (2)
1. input circuit of be used for measuring conductance of liquid, it is characterized in that this input circuit comprises operational amplifier, the in-phase input end of this operational amplifier connects sine-wave oscillator, anti-phase input termination conductance measurement electrode, and resistance is connected across between the output terminal and reverse input end of amplifier.
2. a kind of input circuit for measuring conductance of liquid according to claim 1 is characterized in that described sine-wave oscillator adopts RC bridge-type sine-wave oscillator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012105478237A CN103048546A (en) | 2012-12-11 | 2012-12-11 | Input circuit for measuring liquid electricity conductivity |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012105478237A CN103048546A (en) | 2012-12-11 | 2012-12-11 | Input circuit for measuring liquid electricity conductivity |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103048546A true CN103048546A (en) | 2013-04-17 |
Family
ID=48061255
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012105478237A Pending CN103048546A (en) | 2012-12-11 | 2012-12-11 | Input circuit for measuring liquid electricity conductivity |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103048546A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105444822A (en) * | 2014-08-29 | 2016-03-30 | 桓达科技股份有限公司 | Electromagnetic flow meter with amplitude modulation type measurement function for measuring electrical conductivity of pipeline liquid |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1545204A (en) * | 2003-11-27 | 2004-11-10 | 上海精密科学仪器有限公司 | Circuit for eliminating amplitude temperature drift of Venturi oscillator |
| CN1619318A (en) * | 2004-12-07 | 2005-05-25 | 苏州大学 | Measuring method of electroconductirity of water |
| CN1821763A (en) * | 2006-03-22 | 2006-08-23 | 黄伟忠 | Method for measuring solution conductivity |
| WO2008025775A1 (en) * | 2006-08-30 | 2008-03-06 | Mettler-Toledo Ag | A method for measuring the electrical conductivity of solutions |
| CN203054095U (en) * | 2012-12-11 | 2013-07-10 | 南京化工职业技术学院 | Input circuit used for measuring conductance of liquid |
-
2012
- 2012-12-11 CN CN2012105478237A patent/CN103048546A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1545204A (en) * | 2003-11-27 | 2004-11-10 | 上海精密科学仪器有限公司 | Circuit for eliminating amplitude temperature drift of Venturi oscillator |
| CN1619318A (en) * | 2004-12-07 | 2005-05-25 | 苏州大学 | Measuring method of electroconductirity of water |
| CN1821763A (en) * | 2006-03-22 | 2006-08-23 | 黄伟忠 | Method for measuring solution conductivity |
| WO2008025775A1 (en) * | 2006-08-30 | 2008-03-06 | Mettler-Toledo Ag | A method for measuring the electrical conductivity of solutions |
| CN203054095U (en) * | 2012-12-11 | 2013-07-10 | 南京化工职业技术学院 | Input circuit used for measuring conductance of liquid |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105444822A (en) * | 2014-08-29 | 2016-03-30 | 桓达科技股份有限公司 | Electromagnetic flow meter with amplitude modulation type measurement function for measuring electrical conductivity of pipeline liquid |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C05 | Deemed withdrawal (patent law before 1993) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20130417 |