CN106100592A - A kind of low-frequency amplifier circuit - Google Patents
A kind of low-frequency amplifier circuit Download PDFInfo
- Publication number
- CN106100592A CN106100592A CN201610378546.XA CN201610378546A CN106100592A CN 106100592 A CN106100592 A CN 106100592A CN 201610378546 A CN201610378546 A CN 201610378546A CN 106100592 A CN106100592 A CN 106100592A
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- CN
- China
- Prior art keywords
- resistance
- electrical connected
- operational amplifier
- electric capacity
- low
- 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.)
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- 239000003990 capacitor Substances 0.000 claims description 3
- 230000003321 amplification Effects 0.000 abstract 2
- 238000003199 nucleic acid amplification method Methods 0.000 abstract 2
- 230000005611 electricity Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/26—Modifications of amplifiers to reduce influence of noise generated by amplifying elements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
- G01J5/10—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors
- G01J5/34—Radiation pyrometry, e.g. infrared or optical thermometry using electric radiation detectors using capacitors, e.g. pyroelectric capacitors
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Multimedia (AREA)
- Amplifiers (AREA)
Abstract
The invention discloses a kind of low-frequency amplifier circuit, including signal input part, one-level amplifying circuit, second amplifying circuit and signal output part, described signal input part is electrical connected with one-level input amplifier, described one-level amplification circuit output end passes through electric capacity C3, resistance R5 is electrical connected with second amplifying circuit input, described electric capacity C3 connects with resistance R5, described second amplifying circuit outfan is electrical connected with signal output part, described one-level amplifying circuit includes operational amplifier U1, resistance R4 and electric capacity C2, after described resistance R4 and electric capacity C2 parallel connection, one end is electrical connected with operational amplifier U1 negative input end, the other end is electrical connected with operational amplifier U1 outfan, described second amplifying circuit is identical with one-level amplification circuit structure.Low-voltage, low-frequency voltage signal can be amplified by the present invention, circuit highly sensitive, and noise is less, and stability is higher.
Description
Technical field
The present invention relates to low frequency amplifying technique field, be specially a kind of low-frequency amplifier circuit.
Background technology
Pyroelectric infrared sensor is a kind of sensor detecting human body, and its output voltage signal is the least, about 1mV,
Frequency is generally between 0.1Hz to 10Hz, and this is mainly relevant, so must adopt with the correlative factor such as the translational speed of people
By high-gain, low-frequency amplifier is made necessary processing and amplifying, just can be obtained desired data.Requirement to this low-frequency amplifier is
Bandwidth needs between 0.3Hz to 7Hz, and gain needs also exist for being set between 60dB to 70dB, and this is primarily to suppress
The noise impact on output, in low-frequency amplifier circuit, arranging of bandwidth is the most crucial, because it affects the sensitivity of circuit
And reliability, bandwidth is the widest, and noise is the biggest, and the result caused is that misoperation is the highest, otherwise stability is the highest.
It is thus desirable to a kind of can the amplifying circuit that is amplified of voltage signal low-frequency to low pressure.
Summary of the invention
Present invention aims to above-mentioned the deficiencies in the prior art, it is provided that a kind of low-frequency amplifier circuit.
The technical scheme is that and be achieved in that: a kind of low-frequency amplifier circuit, amplify including signal input part, one-level
Circuit, second amplifying circuit and signal output part, described one-level amplifying circuit includes operational amplifier U1, resistance R4 and electric capacity
C2, after described resistance R4 is in parallel with electric capacity C2, one end is electrical connected with operational amplifier U1 negative input end, and the other end is put with computing
Big device U1 outfan is electrical connected, and described signal input part is electrical connected with operational amplifier U1 outfan by resistance R2, institute
Stating signal input part by resistance R1 ground connection, described resistance R3 one end is electrical connected with signal input part, described resistance R3 another
End be electrical connected with electric capacity C1 one end, described electric capacity C1 other end ground connection, the described resistance R3 other end also with operational amplifier U1
Positive input terminal is electrical connected, and described second amplifying circuit includes U2, electric capacity C5 and resistance R8, and described electric capacity C5 is in parallel with resistance R8
Rear one end is electrical connected with operational amplifier U2 negative input end, and the other end is electrical connected with operational amplifier U2 outfan, described
Operational amplifier U2 outfan is electrical connected with signal output part, and described low-frequency amplifier circuit also includes resistance R6 and resistance R7,
Described resistance R6 one end is electrical connected with+5V voltage, and the other end is electrical connected with resistance R7 one end, another termination of described resistance R7
Ground, described operational amplifier U2 positive input terminal is electrical connected with the resistance R6 other end, and described operational amplifier U2 positive input terminal leads to
Cross electric capacity C4 ground connection.
Preferably, described operational amplifier U1 and operational amplifier U2 all uses LM324 chip.
Preferably, described electric capacity C4 uses polar capacitor, described electric capacity C4 positive pole and operational amplifier U2 positive input terminal electricity
Property be connected, described electric capacity C4 minus earth.
Preferably, the resistance value of described resistance R6 is equal with the resistance value of resistance R7.
Compared with prior art, the invention has the beneficial effects as follows: low-voltage, low-frequency voltage signal can be entered by the present invention
Row amplifies, circuit highly sensitive, and noise is less, and stability is higher.
Accompanying drawing explanation
The present invention is described in further detail for embodiment in below in conjunction with the accompanying drawings, but is not intended that the present invention's
Any restriction.
Fig. 1 is circuit diagram of the present invention.
Detailed description of the invention
Referring to Fig. 1, the present invention provides a kind of technical scheme: a kind of low-frequency amplifier circuit, including signal input part, one-level
Amplifying circuit, second amplifying circuit and signal output part, described one-level amplifying circuit includes operational amplifier U1, resistance R4 and electricity
Holding C2, after described resistance R4 is in parallel with electric capacity C2, one end is electrical connected with operational amplifier U1 negative input end, the other end and computing
Amplifier U1 outfan is electrical connected, and described signal input part is electrical connected with operational amplifier U1 outfan by resistance R2,
Described signal input part passes through resistance R1 ground connection, and described resistance R3 one end is electrical connected with signal input part, and described resistance R3 is another
One end is electrical connected with electric capacity C1 one end, described electric capacity C1 other end ground connection, the described resistance R3 other end also with operational amplifier
U1 positive input terminal is electrical connected, and described second amplifying circuit includes U2, electric capacity C5 and resistance R8, and described electric capacity C5 and resistance R8 is also
After connection, one end is electrical connected with operational amplifier U2 negative input end, and the other end is electrical connected with operational amplifier U2 outfan, institute
Stating operational amplifier U2 outfan to be electrical connected with signal output part, described low-frequency amplifier circuit also includes resistance R6 and resistance
R7, described resistance R6 one end is electrical connected with+5V voltage, and the other end is electrical connected with resistance R7 one end, described resistance R7 another
End ground connection, described operational amplifier U2 positive input terminal is electrical connected with the resistance R6 other end, described operational amplifier U2 positive input
End is by electric capacity C4 ground connection.Described operational amplifier U1 and operational amplifier U2 all uses LM324 chip.Described electric capacity C4 uses
Polar capacitor, described electric capacity C4 positive pole is electrical connected with operational amplifier U2 positive input terminal, described electric capacity C4 minus earth.Described
The resistance value of resistance R6 is equal with the resistance value of resistance R7.
Embodiment provided above is the better embodiment of the present invention, is only used for the convenient explanation present invention, not to this
Bright make any pro forma restriction, any art has usually intellectual, if without departing from the carried skill of the present invention
In the range of art feature, disclosed technology contents is utilized to be made the local Equivalent embodiments that changes or modify, and not
Depart from the technical characteristic content of the present invention, all still fall within the range of the technology of the present invention feature.
Claims (4)
1. a low-frequency amplifier circuit, including signal input part, one-level amplifying circuit, second amplifying circuit and signal output part,
It is characterized in that, described one-level amplifying circuit includes operational amplifier U1, resistance R4 and electric capacity C2, described resistance R4 and electric capacity C2
After parallel connection, one end is electrical connected with operational amplifier U1 negative input end, and the other end is electrical connected with operational amplifier U1 outfan,
Described signal input part is electrical connected with operational amplifier U1 outfan by resistance R2, and described signal input part passes through resistance R1
Ground connection, described resistance R3 one end is electrical connected with signal input part, and the described resistance R3 other end is electrical connected with electric capacity C1 one end,
Described electric capacity C1 other end ground connection, the described resistance R3 other end is also electrical connected with operational amplifier U1 positive input terminal, and described two
Level amplifying circuit includes U2, electric capacity C5 and resistance R8, and after described electric capacity C5 is in parallel with resistance R8, one end is born with operational amplifier U2
Input is electrical connected, and the other end is electrical connected with operational amplifier U2 outfan, described operational amplifier U2 outfan and letter
Number outfan is electrical connected, and described low-frequency amplifier circuit also includes resistance R6 and resistance R7, described resistance R6 one end and+5V voltage
Being electrical connected, the other end is electrical connected with resistance R7 one end, and described resistance R7 other end ground connection, described operational amplifier U2 is the most defeated
Entering end to be electrical connected with the resistance R6 other end, described operational amplifier U2 positive input terminal passes through electric capacity C4 ground connection.
A kind of low-frequency amplifier circuit the most according to claim 1, it is characterised in that described operational amplifier U1 and computing are put
Big device U2 all uses LM324 chip.
A kind of low-frequency amplifier circuit the most according to claim 1, it is characterised in that described electric capacity C4 uses polar capacitor,
Described electric capacity C4 positive pole is electrical connected with operational amplifier U2 positive input terminal, described electric capacity C4 minus earth.
A kind of low-frequency amplifier circuit the most according to claim 1, it is characterised in that the resistance value of described resistance R6 and resistance
The resistance value of R7 is equal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610378546.XA CN106100592A (en) | 2016-05-31 | 2016-05-31 | A kind of low-frequency amplifier circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610378546.XA CN106100592A (en) | 2016-05-31 | 2016-05-31 | A kind of low-frequency amplifier circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106100592A true CN106100592A (en) | 2016-11-09 |
Family
ID=57229670
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610378546.XA Withdrawn CN106100592A (en) | 2016-05-31 | 2016-05-31 | A kind of low-frequency amplifier circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106100592A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200966032Y (en) * | 2006-10-08 | 2007-10-24 | 薛文伟 | Weak AC signal preamplifier circuit |
| CN101589548A (en) * | 2007-01-31 | 2009-11-25 | 麦德托尼克公司 | Chopper-stabilized instrumentation amplifier for impedance measurement |
| CN203071877U (en) * | 2013-03-04 | 2013-07-17 | 滁州学院 | Low-frequency power amplifying circuit |
| CN203416230U (en) * | 2013-08-09 | 2014-01-29 | 天津国强科技有限公司 | Filter |
| CN104639094A (en) * | 2015-01-20 | 2015-05-20 | 国家电网公司 | Filtering circuit |
-
2016
- 2016-05-31 CN CN201610378546.XA patent/CN106100592A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN200966032Y (en) * | 2006-10-08 | 2007-10-24 | 薛文伟 | Weak AC signal preamplifier circuit |
| CN101589548A (en) * | 2007-01-31 | 2009-11-25 | 麦德托尼克公司 | Chopper-stabilized instrumentation amplifier for impedance measurement |
| CN203071877U (en) * | 2013-03-04 | 2013-07-17 | 滁州学院 | Low-frequency power amplifying circuit |
| CN203416230U (en) * | 2013-08-09 | 2014-01-29 | 天津国强科技有限公司 | Filter |
| CN104639094A (en) * | 2015-01-20 | 2015-05-20 | 国家电网公司 | Filtering circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20161109 |
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| WW01 | Invention patent application withdrawn after publication |