CN205898622U - A processing circuit for light scattering method raise dust monitor - Google Patents
A processing circuit for light scattering method raise dust monitor Download PDFInfo
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- CN205898622U CN205898622U CN201620838827.4U CN201620838827U CN205898622U CN 205898622 U CN205898622 U CN 205898622U CN 201620838827 U CN201620838827 U CN 201620838827U CN 205898622 U CN205898622 U CN 205898622U
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Abstract
The utility model discloses a processing circuit for light scattering method raise dust monitor, including photoelectric detector, small signal sampling circuit, filtering and amplifying circuit, comparison discriminator circuit, photoelectric detector and small signal sampling circuit are connected, and the PN junction in the photoelectric detector adds reverse bias, and small signal sampling circuit and filtering and amplifying circuit are connected, filtering and amplifying circuit and relatively examine circuit connection, and the comparison discriminator circuit is connected with microprocessor. The utility model relates to a precision is high, the response is quick, stability is good, can directly be applied to the signal acquisition and the processing of light scattering method raise dust monitor.
Description
Technical field
This utility model is related to ambient air particulate matter (pm10/pm2.5Deng) field is and in particular to a kind of be used for light scattering method
The signal processing circuit of airborne dust monitor.
Background technology
The monitor method of ambient air particulate matter can be divided mainly into: (1) β ray method；(2) oscillating balance method；(3) light dissipates
Penetrate method.Wherein, β ray method instrument maintenance low cost but measure the cycle is long, oscillating balance method Instrument measuring precision is high but operation is multiple
Miscellaneous.The key components and partss of both instruments rely primarily on import simultaneously, and instrument cost is higher, are not suitable for the large spaces such as industrial park
In the range of ambient air particulate matter monitoring requirements.Light scattering method airborne dust monitor adopts cheap semiconductor laser conduct
Light source, photodiode, as photodetector, just can realize ambient air particulate matter by designing simple optical texture
Fast monitored.Because its cost is relatively low, it is particularly suitable for large area, the monitoring of layouting in wide scope, the market demand is urgent.
Utility model content
The purpose of this utility model be provide a kind of design accuracy high, good stability for light scattering method airborne dust monitor
Signal processing circuit.
The technical solution adopted in the utility model is:
A kind of signal processing circuit for light scattering method airborne dust monitor it is characterised in that: include photodetector, micro-
Weak signal sample circuit, filter amplification circuit, compare discriminator circuit；Described photodetector is with small-signal sample circuit even
Connect, the pn-junction in photodetector adds reverse bias, small-signal sample circuit is connected with filter amplification circuit, filter and amplification electricity
Road is connected with comparing discriminator circuit, compares discriminator circuit and is connected with microprocessor.
A kind of described signal processing circuit for light scattering method airborne dust monitor it is characterised in that: described smooth electrical resistivity survey
Survey device and include photodiode d1, small-signal sample circuit includes resistance r4, electric capacity c3, and filter amplification circuit includes
Operational amplifier u1a, u1b, compare discriminator circuit and include voltage comparator u3a, the positive pole of photodiode d1 accesses computing
The inverting input of amplifier u1a, bridging between the inverting input of operational amplifier u1a and outfan has the resistance being in parallel
R4, electric capacity c3, the output voltage of operational amplifier u1a is linked into the inverting input of operational amplifier u1b through electric capacity c6, fortune
Calculate another input of amplifier u1b to be grounded by resistance r9, the outfan of operational amplifier u1b accesses 3 feet of voltage comparator,
The resistance that 2 feet of voltage comparator pass through the different resistance of series connection obtains different reference voltages, by arranging different magnitudes of voltage
The i/o mouth obtaining pulse signal to the microprocessor of different frequency is counted.
A kind of described signal processing circuit for light scattering method airborne dust monitor it is characterised in that: described faint letter
The resistance of number sample circuit resistance r4 is 4m ω, and the capacitance of electric capacity c3 is 2.2pf.
A kind of described signal processing circuit for light scattering method airborne dust monitor it is characterised in that: described computing is put
Model opa2132u of big device u1a, u1b.
A kind of described signal processing circuit for light scattering method airborne dust monitor it is characterised in that: described voltage ratio
Model lm393 compared with device.
Principle of the present utility model is:
Photodetector exports the current signal of very little, and signal processing circuit is exactly first current signal to be converted to voltage
Signal, is then filtered to signal, amplifies and screens, and finally exports continuous potential pulse.If real using series resistance
Existing i/v conversion, then a higher voltage will be obtained and require that the resistance of load resistance is very big.Resistance is bigger, reality output
The upper cut-off frequency of circuit is less, the larger pressure drop that output current produces on load resistance simultaneously, lead to probably due to
Output signal saturation and cause photodetector output nonlinear.Load resistance is replaced to realize current/voltage using operational amplifier
Conversion just can solve the above problems.The straight of hundreds of mv or a few v is typically include in voltage signal after amplifier sampling
Flow component.Signal circuit of very little when the amplifying circuit of next stage can make signal reach saturation.Therefore, then carry out two
DC component in signal is filtered by an electric capacity of first will connecting in circuit before secondary amplification.Signal amplitude after secondary amplification
Change in the range of (0-5) v.Signal can be accessed discriminator circuit, by arranging different threshold values, pulse separation is several groups
Different pulse signals, corresponds to the signal intensity of different-grain diameter (tsp, pm10, pm4, pm2.5) respectively.Signal processing circuit
It is critical only that the rc parameter setting match circuit, the sample resistance that this utility model selects is 4m ω, filter capacitor is 1uf.
In one 2.2pf electric capacity of resistor in parallel on sample circuit, it is possible to reduce the high-frequency noise in signal, can also change
Kind signal to noise ratio.
The beneficial effect that this utility model adopts is:
This utility model design accuracy height, response quickly, good stability, may be directly applied to light scattering method airborne dust monitor
Signal sampling and processing.
Brief description
Fig. 1 is this utility model schematic diagram.
Fig. 2 is this utility model circuit diagram.
Specific embodiment
With reference to Fig. 1 and Fig. 2, this utility model is described further.
A kind of signal processing circuit for light scattering method airborne dust monitor, including photodetector 1, small-signal sampling
Circuit 2, filter amplification circuit 3, compare discriminator circuit 4；Photodetector is connected with 1 small-signal sample circuit 2, photodetection
Pn-junction in device 1 adds reverse bias, and small-signal sample circuit 2 is connected with filter amplification circuit 3, filter amplification circuit 3 with than
Connect compared with discriminator circuit 4, compare discriminator circuit 4 and be connected with microprocessor 5.
Photodetector includes photodiode d1, and small-signal sample circuit includes resistance r4, electric capacity c3, filtering
Amplifying circuit includes operational amplifier u1a, u1b, compares discriminator circuit and includes voltage comparator u3a, photodiode d1
Positive pole access operational amplifier u1a inverting input, between the inverting input of operational amplifier u1a and outfan bridge
There are the resistance r4 being in parallel, electric capacity c3, the output voltage of operational amplifier u1a is linked into operational amplifier u1b through electric capacity c6
Inverting input, another input of operational amplifier u1b is grounded by resistance r9, and the outfan of operational amplifier u1b accesses
3 feet of voltage comparator, 2 feet of voltage comparator obtain different reference voltages by the resistance of the different resistances of series connection, pass through
The i/o mouth arranging pulse signal to the microprocessor that different voltages are worth to different frequency is counted.
The resistance of small-signal sample circuit resistance r4 is 4m ω, and the capacitance of electric capacity c3 is 2.2pf.Operational amplifier u1a,
Model opa2132u of u1b.Model lm393 of voltage comparator.
Claims (5)
1. a kind of signal processing circuit for light scattering method airborne dust monitor it is characterised in that: include photodetector, faint
Signal sampling circuit, filter amplification circuit, compare discriminator circuit；Described photodetector is connected with small-signal sample circuit,
Pn-junction in photodetector adds reverse bias, and small-signal sample circuit is connected with filter amplification circuit, filter amplification circuit
It is connected with comparing discriminator circuit, compare discriminator circuit and be connected with microprocessor.
2. a kind of signal processing circuit for light scattering method airborne dust monitor according to claim 1 it is characterised in that:
Described photodetector includes photodiode d1, and small-signal sample circuit includes resistance r4, electric capacity c3, filter and amplification
Circuit includes operational amplifier u1a, u1b, compares discriminator circuit and includes voltage comparator u3a, photodiode d1 is just
The inverting input of operational amplifier u1a is accessed in pole, and bridging between the inverting input of operational amplifier u1a and outfan has phase
Resistance r4, electric capacity c3 in parallel, the output voltage of operational amplifier u1a is linked into the anti-of operational amplifier u1b through electric capacity c6
Phase input, another input of operational amplifier u1b is grounded by resistance r9, and the outfan of operational amplifier u1b accesses voltage
3 feet of comparator, 2 feet of voltage comparator obtain different reference voltages by the resistance of the different resistances of series connection, by setting
The i/o mouth that different voltage is worth to pulse signal to the microprocessor of different frequency is counted.
3. a kind of signal processing circuit for light scattering method airborne dust monitor according to claim 2 it is characterised in that:
The resistance of described small-signal sample circuit resistance r4 is 4m ω, and the capacitance of electric capacity c3 is 2.2pf.
4. a kind of signal processing circuit for light scattering method airborne dust monitor according to claim 2 it is characterised in that:
Model opa2132u of described operational amplifier u1a, u1b.
5. a kind of signal processing circuit for light scattering method airborne dust monitor according to claim 2 it is characterised in that:
Model lm393 of described voltage comparator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620838827.4U CN205898622U (en) | 2016-08-04 | 2016-08-04 | A processing circuit for light scattering method raise dust monitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620838827.4U CN205898622U (en) | 2016-08-04 | 2016-08-04 | A processing circuit for light scattering method raise dust monitor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205898622U true CN205898622U (en) | 2017-01-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620838827.4U Active CN205898622U (en) | 2016-08-04 | 2016-08-04 | A processing circuit for light scattering method raise dust monitor |
Country Status (1)
| Country | Link |
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| CN (1) | CN205898622U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108007833A (en) * | 2017-11-20 | 2018-05-08 | 合肥硕佳电子科技有限公司 | A kind of automatic range dust detector |
| CN108039013A (en) * | 2017-10-25 | 2018-05-15 | 宁波威兹马特电子有限公司 | Scatter-type infrared light electric-type smoke fire detector smokescope signal amplification circuit |
-
2016
- 2016-08-04 CN CN201620838827.4U patent/CN205898622U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108039013A (en) * | 2017-10-25 | 2018-05-15 | 宁波威兹马特电子有限公司 | Scatter-type infrared light electric-type smoke fire detector smokescope signal amplification circuit |
| CN108007833A (en) * | 2017-11-20 | 2018-05-08 | 合肥硕佳电子科技有限公司 | A kind of automatic range dust detector |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: 230000 Huguang Road Independent Innovation Industrial Base, Shushan Economic Development Zone, Hefei City, Anhui Province Patentee after: Anhui Anguang Environmental Technology Co., Ltd. Address before: Tianda high tech Zone 230031 Hefei Road, Anhui province No. 71 Huayi Science Park C-201 Patentee before: Anhui Province Anguang Environmental Optical Engineering Technology Research Center Co., Ltd. |
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| CP03 | Change of name, title or address |