CN207408332U - The pH signal conditioning circuits of water body pH detecting systems - Google Patents
The pH signal conditioning circuits of water body pH detecting systems Download PDFInfo
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- CN207408332U CN207408332U CN201721391957.9U CN201721391957U CN207408332U CN 207408332 U CN207408332 U CN 207408332U CN 201721391957 U CN201721391957 U CN 201721391957U CN 207408332 U CN207408332 U CN 207408332U
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Abstract
The utility model discloses the pH signal conditioning circuits of water body pH detecting systems, including impedance matching network, primary operational amplifier circuit, programmable amplifying circuit and the voltage follower being sequentially connected, input terminal of the input terminal of the impedance matching network as pH signal conditioning circuits, the output terminal of the output terminal of the voltage follower as pH signal conditioning circuits.Weak voltage signals from PH electrodes first carry out impedance matching, it is re-fed into rear stage and pre-amplification is carried out to signal by the primary operational amplifier circuit that low offset voltage operational amplifier is formed, purpose is the input signal strength for improving programmable amplifying circuit, gain is stepped up by programmable amplifying circuit again, measurement is finely divided to pH signals, improve the resolution ratio and measurement accuracy of pH value voltage signal to the full extent.
Description
Technical field
The utility model is related to water body pH detecting systems, and in particular to the pH signal conditioning circuits of water body pH detecting systems.
Background technology
There is vital effect at water source to the health of resident, once water quality parameter is more than national safety standard,
Directly harm will be generated to health.If the pH (acid-base value) of water is exceeded, the acid-base balance of human body is influenced whether, it is long
Phase drinks the exceeded water of pH value and body immunity but will be caused to decline, and induces panimmunity class disease.
With the promotion of quality of life in all parts of the country, people also more pay attention to the safety of drinking water, so region
The standard of water quality detection is also promoted constantly, and the high standard of water quality, tight requirement are to the ability of China's water quality detection and technology water
The flat challenge for proposing bigger.Existing water body pH detecting systems generally amplify pH electrodes using fixed gain amplifier
Signal, when small variations occur for water quality pH, PH combination electrodes output change in electric very little（It can according to Nernst equation
Know）, then also with regard to very little, the AD conversion device of water body pH detecting systems can not divide the output voltage that fixed gain amplifier obtains
It distinguishes, measurement accuracy is relatively low.
The content of the invention
The technical problem to be solved by the present invention is to provide a kind of PH signal conditioning circuits of water body pH detecting systems, can
Amplify the signal of pH electrodes to solve the pH signal conditioning circuits of existing water body pH detecting systems using fixed gain amplifier,
The problem of causing measurement accuracy relatively low.
The utility model is achieved through the following technical solutions：
The pH signal conditioning circuits of water body pH detecting systems, including impedance matching network, the primary amplifier electricity being sequentially connected
Road, programmable amplifying circuit and voltage follower, the input of the input terminal of the impedance matching network as pH signal conditioning circuits
End, the output terminal of the output terminal of the voltage follower as pH signal conditioning circuits.
The further scheme of the utility model is that the impedance matching network includes operational amplifier U3, and the computing is put
The 1st pin and the 5th pin of big device U3 connect two definite value ends of potentiometer R2 respectively, and adjustable end and the computing of potentiometer R2 are put
In the first power cathode, first power cathode also connects the 4th pins in parallel of big device U3 through capacitance C1, capacitance C4 in parallel
Ground；The 2nd pin and the 6th pins in parallel of the operational amplifier U3 is in the input terminal of primary operational amplifier circuit；The operation amplifier
The 3rd pin connection input signal anode of device U3；The 7th pin of the operational amplifier U3 connects the first positive pole, described
First positive pole is also grounded through capacitance C9, capacitance C13 in parallel.
The further scheme of the utility model is that the primary operational amplifier circuit includes low offset voltage operational amplifier U2,
The 2nd pin of the operational amplifier U2 is through resistance R4 connection impedance matching network output terminals, and the 3rd of the operational amplifier U2 the
Pin is grounded through resistance R3, and the 4th pin connection second source cathode of the operational amplifier U2, the second source cathode is also
It is grounded through capacitance C2, capacitance C5 in parallel；The 6th pin of the operational amplifier U2 connects three articles of branches, the wherein first branch
Programmable amplifying circuit input terminal is connected, the second branch is grounded through resistance R1, and the 3rd branch is through capacitance C8 in parallel, resistance R5 connections
The 2nd pin of operational amplifier U2；The 7th pin connection second source anode of the operational amplifier U2, the second source
Anode is also grounded through capacitance C10, capacitance C14 in parallel.
The further scheme of the utility model is that the programmable amplifying circuit includes programmable gain amplifier U1, described
VIN- pins, DGND pins, the REF pins of programmable gain amplifier U1 is grounded respectively, and V+ pins and V- pins connect respectively
3rd positive pole and the 3rd power cathode, the 3rd positive pole are grounded through capacitance C3, C6 in parallel, the 3rd power cathode
It is grounded through capacitance C12, C15 in parallel；The primary operational amplifier circuit output terminal of VIN+ pins connection, A0 pins and A1 pins connect respectively
A2 pins and A3 pins, the A2 pins and A3 pins are also grounded through resistance R7, resistance R8 respectively；FeedBack pins and VOUT
Voltage follower is connected after pins in parallel, two VADJ pins connect two definite value ends of potentiometer R6, the potentiometer respectively
The adjustable end of R6 connects the 4th positive pole.
The further scheme of the utility model is that the voltage follower includes operational amplifier U4, the operation amplifier
The 3rd pin connection programmable amplifying circuit output terminal of device U4, the 4th pin and the 7th pin of the operational amplifier U4 connect respectively
The 5th power cathode and the 5th positive pole are connect, the 5th power cathode and the 5th positive pole are respectively through capacitance C7 and capacitance
C11 is grounded；The 2nd pin and the 6th pins in parallel of the operational amplifier U4 is as output terminal.
The utility model compared with prior art the advantages of be：
Weak voltage signals from pH electrodes first carry out impedance matching, are re-fed into rear stage and are put by low offset voltage computing
The primary operational amplifier circuit that big device is formed carries out pre-amplification to signal, it is therefore intended that the input signal for improving programmable amplifying circuit is strong
Degree, then gain is stepped up by programmable amplifying circuit, measurement is finely divided to pH signals, pH value voltage is improved to the full extent
The resolution ratio and measurement accuracy of signal.
Description of the drawings
Fig. 1 is the circuit diagram of the utility model.
Specific embodiment
The pH signal conditioning circuits of water body pH detecting systems as shown in Figure 1, including be sequentially connected impedance matching network,
Primary operational amplifier circuit, programmable amplifying circuit and voltage follower, the input terminal of the impedance matching network is as pH signal conditions
The input terminal connection pH combination electrodes of circuit, the output terminal of the voltage follower connect as the output terminal of pH signal conditioning circuits
The processor of water receiving body pH detecting systems.
The impedance matching network include CA3140 type operational amplifiers U3, the 1st pin of the operational amplifier U3 and
5th pin connects two definite value ends of potentiometer R2 respectively, and the adjustable end of potentiometer R2 and the 4th pin of operational amplifier U3 are simultaneously
The first power cathode is coupled to, first power cathode is also grounded through capacitance C1, capacitance C4 in parallel；The operational amplifier U3
The 2nd pin and the 6th pins in parallel in the input terminal of primary operational amplifier circuit；The 3rd pin connection of the operational amplifier U3 is defeated
Enter signal anode；The 7th pin of the operational amplifier U3 connects the first positive pole, and first positive pole is also through parallel connection
Capacitance C9, capacitance C13 ground connection.
The primary operational amplifier circuit includes the of OP07 types low offset voltage operational amplifier U2, the operational amplifier U2
2 pins are grounded through resistance R4 connection impedance matching network output terminals, the 3rd pin of the operational amplifier U2 through resistance R3, institute
The 4th pin connection second source cathode of operational amplifier U2 is stated, the second source cathode is also through capacitance C2 in parallel, capacitance
C5 is grounded；The 6th pin of the operational amplifier U2 connects three articles of branches, wherein first branch connection programmable amplifying circuit input
End, the second branch are grounded through resistance R1, and capacitance C8 of the 3rd branch through parallel connection, the 2nd of resistance R5 concatenation operation amplifiers U2 the are drawn
Foot；The 7th pin connection second source anode of the operational amplifier U2, the second source anode is also through capacitance in parallel
C10, capacitance C14 are grounded.
The programmable amplifying circuit includes PGA204AU type programmable gain amplifier U1, the programmable gain amplifier
VIN- pins, DGND pins, the REF pins of U1 is grounded respectively, and V+ pins and V- pins connect the 3rd positive pole and respectively
Three power cathodes, the 3rd positive pole are grounded through capacitance C3, C6 in parallel, capacitance C12 of the 3rd power cathode through parallel connection,
C15 is grounded；The primary operational amplifier circuit output terminal of VIN+ pins connection, A0 pins and A1 pins connect A2 pins and A3 pins respectively,
The A2 pins and A3 pins are also grounded through resistance R7, resistance R8 respectively；It is connected after FeedBack pins and VOUT pins in parallel
Voltage follower, two VADJ pins connect two definite value ends of potentiometer R6, the adjustable end connection of the potentiometer R6 respectively
4th positive pole.
The 3rd pin that the voltage follower includes OP07GSZ type operational amplifiers U4, the operational amplifier U4 connects
Programmable amplifying circuit output terminal, the 4th pin and the 7th pin of the operational amplifier U4 connect the 5th power cathode and respectively
Five positive poles, the 5th power cathode and the 5th positive pole are grounded respectively through capacitance C7 and capacitance C11；The computing is put
The 2nd pin and the 6th pins in parallel of big device U4 is as output terminal.
Claims (5)
1. the pH signal conditioning circuits of water body pH detecting systems, it is characterised in that：Including be sequentially connected impedance matching network, just
Grade operational amplifier circuit, programmable amplifying circuit and voltage follower, the input terminal of the impedance matching network is as pH signal conditions electricity
The input terminal on road, the output terminal of the output terminal of the voltage follower as pH signal conditioning circuits.
2. the pH signal conditioning circuits of water body pH detecting systems as described in claim 1, it is characterised in that：The impedance matching
The 1st pin and the 5th pin that network includes CA3140 type operational amplifiers U3, the operational amplifier U3 connect potentiometer respectively
Two definite value ends of R2, the adjustable end of potentiometer R2 and the 4th pins in parallel of operational amplifier U3 are described in the first power cathode
First power cathode is also grounded through capacitance C1, capacitance C4 in parallel；The 2nd pin and the 6th pin of the operational amplifier U3 is simultaneously
It is coupled to the input terminal of primary operational amplifier circuit；The 3rd pin connection input signal anode of the operational amplifier U3；The computing is put
The 7th pin of big device U3 connects the first positive pole, and first positive pole is also grounded through capacitance C9, capacitance C13 in parallel.
3. the pH signal conditioning circuits of water body pH detecting systems as described in claim 1, it is characterised in that：The primary amplifier
The 2nd pin that circuit includes OP07 types low offset voltage operational amplifier U2, the operational amplifier U2 is hindered through resistance R4 connections
Anti- matching network output terminal, the 3rd pin of the operational amplifier U2 are grounded through resistance R3, and the 4th of the operational amplifier U2 the
Pin connects second source cathode, and the second source cathode is also grounded through capacitance C2, capacitance C5 in parallel；The operation amplifier
The 6th pin of device U2 connects three articles of branches, wherein first branch connection programmable amplifying circuit input terminal, and the second branch is through resistance R1
Ground connection, 2nd pin of the 3rd branch through capacitance C8 in parallel, resistance R5 concatenation operation amplifiers U2；The operational amplifier U2
The 7th pin connection second source anode, the second source anode is also grounded through in parallel capacitance C10, capacitance C14.
4. the pH signal conditioning circuits of water body pH detecting systems as described in claim 1, it is characterised in that：The programming amplifying
Circuit includes PGA204AU type programmable gain amplifiers U1, and VIN- pins, the DGND of the programmable gain amplifier U1 draw
Foot, REF pins are grounded respectively, and V+ pins and V- pins connect the 3rd positive pole and the 3rd power cathode respectively, and the described 3rd
Positive pole is grounded through capacitance C3, C6 in parallel, and the 3rd power cathode is grounded through capacitance C12, C15 in parallel；VIN+ pins connect
Primary operational amplifier circuit output terminal is connect, A0 pins and A1 pins connect A2 pins and A3 pins, the A2 pins and A3 pins respectively
Also it is grounded respectively through resistance R7, resistance R8；Voltage follower, two VADJ are connected after FeedBack pins and VOUT pins in parallel
Pin connects two definite value ends of potentiometer R6 respectively, and the adjustable end of the potentiometer R6 connects the 4th positive pole.
5. the pH signal conditioning circuits of water body pH detecting systems as described in claim 1, it is characterised in that：The voltage follow
Device includes the 3rd pin connection programmable amplifying circuit output terminal of OP07GSZ type operational amplifiers U4, the operational amplifier U4,
The 4th pin and the 7th pin of the operational amplifier U4 connects the 5th power cathode and the 5th positive pole respectively, and the described 5th
Power cathode and the 5th positive pole are grounded respectively through capacitance C7 and capacitance C11；The 2nd pin of the operational amplifier U4 and
6 pins in parallel are as output terminal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721391957.9U CN207408332U (en) | 2017-10-26 | 2017-10-26 | The pH signal conditioning circuits of water body pH detecting systems |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721391957.9U CN207408332U (en) | 2017-10-26 | 2017-10-26 | The pH signal conditioning circuits of water body pH detecting systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207408332U true CN207408332U (en) | 2018-05-25 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721391957.9U Expired - Fee Related CN207408332U (en) | 2017-10-26 | 2017-10-26 | The pH signal conditioning circuits of water body pH detecting systems |
Country Status (1)
| Country | Link |
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| CN (1) | CN207408332U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111464143A (en) * | 2020-04-03 | 2020-07-28 | 南京中岭艾恩环保科技有限公司 | Circuit for conditioning electric signals of electrostatic sensor |
-
2017
- 2017-10-26 CN CN201721391957.9U patent/CN207408332U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111464143A (en) * | 2020-04-03 | 2020-07-28 | 南京中岭艾恩环保科技有限公司 | Circuit for conditioning electric signals of electrostatic sensor |
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Legal Events
| Date | Code | Title | Description |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180525 Termination date: 20191026 |