CN215574636U - Air particulate matter detection circuit, air particulate matter detector and air purifier - Google Patents
Air particulate matter detection circuit, air particulate matter detector and air purifier Download PDFInfo
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- CN215574636U CN215574636U CN202120220053.XU CN202120220053U CN215574636U CN 215574636 U CN215574636 U CN 215574636U CN 202120220053 U CN202120220053 U CN 202120220053U CN 215574636 U CN215574636 U CN 215574636U
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Abstract
The embodiment of the utility model relates to the technical field of detection, and discloses an air particulate matter detection circuit, an air particulate matter detector and an air purifier. The circuit comprises: the device comprises a light emitting module, a light sensing module, a signal amplifying module, a filtering module and a signal processing module; the light emitting module is used for generating an optical signal; the optical sensing module is used for receiving a scattered light signal formed after the light signal passes through air particles and generating a current signal according to the scattered light signal; the signal amplification module is used for converting and amplifying the current signal into a voltage signal and transmitting the voltage signal to the filtering module; the filtering module is used for filtering the voltage signal and transmitting the voltage signal after filtering to the signal processing module; and the signal processing module is used for carrying out signal processing on the voltage signal after filtering processing so as to generate an air particulate matter detection result. The embodiment of the utility model has a simple structure and can accurately detect the particulate matters in the air.
Description
Technical Field
The embodiment of the utility model relates to the technical field of detection, in particular to an air particle detection circuit, an air particle detector and an air purifier.
Background
With the enhancement of environmental awareness of people, the air quality detection is more and more widely applied. Air particulate matters are one of the indexes of air quality, and are mainly used for detecting the concentration and the size of the particulate matters in the air.
In the related art, air particulate detection is performed by an optical measurement instrument. Commonly used optical measurement instruments for airborne particulate detection include photometers and optical particle counters. However, both photometers and optical particle counters have drawbacks when performing airborne particle detection. The particle size of the air particles can not be measured when the photometer detects the air particles, and the optical particle counter can not detect the air particles with higher concentration.
SUMMERY OF THE UTILITY MODEL
In view of the above problems, embodiments of the present invention provide an air particulate matter detection circuit, an air particulate matter detector, and an air purifier, which implement accurate detection of particulate matter in air.
According to an aspect of an embodiment of the present invention, there is provided an airborne particle detection circuit, the circuit comprising: the device comprises a light emitting module, a light sensing module, a signal amplifying module, a filtering module and a signal processing module;
the light emitting module is used for generating a light signal;
the optical sensing module is used for receiving scattered light signals formed after the optical signals pass through the air particles and generating current signals according to the scattered light signals;
the signal amplification module is used for converting and amplifying the current signal into a voltage signal and transmitting the voltage signal to the filtering module;
the filtering module is used for filtering the voltage signal and transmitting the filtered voltage signal to the signal processing module;
and the signal processing module is used for carrying out signal processing on the voltage signal after filtering processing so as to generate an air particulate matter detection result.
In an alternative form, the light emitting module includes: the light-emitting unit is connected with the switch unit;
the light-emitting unit comprises a positive terminal and a negative terminal;
the switch unit comprises an input end, a control end and an output end;
the positive end of the light-emitting unit is connected with a direct-current power supply, and the negative end of the light-emitting unit is connected with the input end of the switch unit;
the control end of the switch unit is connected with the drive circuit, and the output end of the switch unit is grounded.
In an alternative mode, the light emitting unit includes a light emitting diode, and the switching unit includes a transistor.
In an alternative approach, the light sensing module includes a photodiode.
In an alternative form, the signal amplification module includes: the first operational amplifier, the second operational amplifier, the third resistor and the fourth resistor;
the positive phase input end of the first operational amplifier is connected with a direct current power supply, the negative phase input end of the first operational amplifier is connected with one end of the third resistor, and the output end of the first operational amplifier is connected with the other end of the third resistor;
one end of the third resistor is connected with the positive electrode end of the photodiode, and the other end of the third resistor is connected with the negative phase input end of the third operational amplifier;
the negative end of the photodiode is respectively connected with one end of the fourth resistor and the negative phase input end of the second operational amplifier;
the positive phase input end of the second operational amplifier is connected with the direct current power supply, and the output end of the second operational amplifier is connected with the other end of the fourth resistor;
the other end of the fourth resistor is also connected with a positive phase input end of the third operational amplifier;
and the output end of the third operational amplifier is connected with the negative phase input end and is connected with the filtering module.
In an optional manner, the filtering module includes a first-order filtering unit and a second-order filtering unit, and the first-order filtering unit is connected to the second-order filtering unit;
the first-order filtering unit is connected with the signal amplifying module;
the second-order filtering unit is connected with the signal processing module.
In an alternative manner, the first-order filtering unit includes: the first capacitor, the second capacitor, the fifth resistor, the sixth resistor, the seventh resistor and the fourth operational amplifier;
one end of the first capacitor is connected with the signal amplification module, and the other end of the first capacitor is respectively connected with one end of the fifth resistor and the positive phase input end of the fourth operational amplifier;
the other end of the fifth resistor is grounded;
a negative phase input end of the fourth operational amplifier is respectively connected with one end of the sixth resistor, one end of the seventh resistor and one end of the second capacitor, and an output end of the fourth operational amplifier is respectively connected with the other end of the seventh resistor, the other end of the second capacitor and the second-order filtering unit;
the other end of the sixth resistor is grounded.
In an optional manner, the second-order filtering unit includes: a third capacitor, a fourth capacitor, an eighth resistor, a ninth resistor, a tenth resistor and a fifth operational amplifier;
one end of the third capacitor is connected with the first-order filtering unit, and the other end of the third capacitor is respectively connected with one end of the eighth resistor and the positive-phase input end of the fifth operational amplifier;
the other end of the eighth resistor is grounded;
a negative phase input end of the fifth operational amplifier is respectively connected with one end of the ninth resistor, one end of the tenth resistor and one end of the fourth capacitor, and an output end of the fifth operational amplifier is respectively connected with the other end of the tenth resistor, the other end of the fourth capacitor and the signal processing module;
the other end of the ninth resistor is grounded.
According to another aspect of embodiments of the present invention, there is provided an airborne particulate matter detector including the airborne particulate matter detection circuit described above.
According to a further aspect of an embodiment of the present invention, there is provided an air purifier including the above-described air particulate matter detection circuit.
The embodiment of the utility model is provided with a light-emitting module, a light sensing module, a signal amplification module, a filtering module and a signal processing module; the light emitting module generates a light signal, the light sensing module can receive a scattered light signal formed by the light signal passing through air particles, and a current signal is generated according to the scattered light signal; the signal amplification module further amplifies the current signal into a voltage signal and transmits the voltage signal to the filtering module; the filtering module carries out filtering processing on the voltage signal, and the signal processing module carries out signal processing on the voltage signal after the filtering processing so as to generate an air particulate matter detection result. According to the embodiment of the utility model, the size of the air particulate matters can be detected according to the amplitude of the voltage signals, and the concentration of the air particulate matters is detected according to the number of the voltage signals, so that the detection result is more accurate.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the utility model. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 illustrates a block diagram of an air particulate detector provided by an embodiment of the present invention;
fig. 2 is a block diagram showing the construction of an air purifier provided by an embodiment of the present invention;
fig. 3 is a block diagram illustrating a configuration of an air particle detection circuit according to an embodiment of the present invention;
fig. 4 is a block diagram illustrating another air particle detection circuit according to an embodiment of the present invention;
fig. 5 is a circuit diagram of an air particle detection circuit according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and therefore are only examples, and the protection scope of the present invention is not limited thereby.
FIG. 1 shows a block diagram of an air particulate detector provided by an embodiment of the present invention. Referring to FIG. 1, the air particulate matter detector includes an air particulate matter detection circuit. The air particulate matter detection circuit is used for detecting the particulate matter in the air, including but not limited to detecting the size and the quantity of the particulate matter in the air.
Fig. 2 shows a block diagram of an air purifier according to an embodiment of the present invention. Referring to fig. 2, the air purifier includes an air particulate matter detection circuit. The air particulate matter detection circuit is used for detecting the particulate matter in the air, including but not limited to detecting the size and the quantity of the particulate matter in the air.
Fig. 3 is a block diagram illustrating a configuration of an air particle detection circuit according to an embodiment of the present invention. The air particulate matter detection circuit may be applied to the air purifier described above. Referring to fig. 3, the air particle detection circuit includes: the light emitting module 10, the light sensing module 20, the signal amplifying module 30, the filtering module 40 and the signal processing module 50.
A light emitting module 10 for generating an optical signal;
the optical sensing module 20 is configured to receive a scattered light signal formed after the optical signal passes through the air particulate matter, and generate a current signal according to the scattered light signal;
the signal amplifying module 30 is configured to amplify the current signal into a voltage signal, and transmit the voltage signal to the filtering module 40;
the filtering module 40 is configured to perform filtering processing on the voltage signal, and transmit the filtered voltage signal to the signal processing module 50;
and the signal processing module 50 is configured to perform signal processing on the filtered voltage signal to generate an air particulate detection result.
The embodiment of the utility model is provided with a light-emitting module, a light sensing module, a signal amplification module, a filtering module and a signal processing module; the light emitting module generates a light signal, the light sensing module can receive a scattered light signal formed by the light signal passing through air particles, and a current signal is generated according to the scattered light signal; the signal amplification module further amplifies the current signal into a voltage signal and transmits the voltage signal to the filtering module; the filtering module carries out filtering processing on the voltage signal, and the signal processing module carries out signal processing on the voltage signal after the filtering processing so as to generate an air particulate matter detection result. The circuit of the embodiment of the utility model has simple structure and can accurately detect the particles in the air.
Fig. 4 is a block diagram illustrating another air particle detection circuit according to an embodiment of the present invention. The air particulate matter detection circuit may be applied to the air purifier described above. Please refer to fig. 4, in which: the light emitting module 10 includes: the light emitting unit 11 and the switch unit 12, wherein the light emitting unit 11 and the switch unit 12 are connected;
the light emitting unit 11 includes a positive terminal 111 and a negative terminal 112;
the switching unit 12 includes an input terminal 122, a control terminal 121, and an output terminal 123;
the positive terminal 111 of the light-emitting unit 11 is connected with a direct-current power supply, and the negative terminal is connected with the input terminal 122 of the switch unit 12;
the control terminal 121 of the switch unit 12 is connected to the driving circuit, and the output terminal 123 is grounded.
The light emitting module provided by the embodiment of the utility model can emit light through the light emitting unit and the switch unit, and the switch unit controls the light emitting unit to be switched on or switched off, so that the light emitting unit is controlled to emit light when being switched on and not emit light when being switched off, and the air particle detection circuit provided by the embodiment of the utility model is indirectly controlled to execute air particle detection or not execute the air particle detection.
Fig. 5 shows a circuit schematic of an air particulate matter detection circuit according to an embodiment of the present invention. The air particulate matter detection circuit may be applied to the air purifier described above.
Referring to fig. 5, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, a resistor R10, and a resistor R11 are respectively used to identify a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor; the capacitor C1, the capacitor C2, the capacitor C3 and the capacitor C4 are respectively used for identifying a first capacitor, a second capacitor, a third capacitor and a fourth capacitor; the operational amplifier U1, operational amplifier U2, operational amplifier U3, operational amplifier U4, and operational amplifier U5 are used to identify a first operational amplifier, a second operational amplifier, a third operational amplifier, a fourth operational amplifier, and a fifth operational amplifier, respectively.
The light emitting unit of the light emitting module 10 includes a light emitting diode D1, and the switching unit includes a transistor Q1. The input end of the switch unit is a collector c of a triode Q1, the control end is a base b of a triode Q1, and the output end is an emission set e of a triode Q1.
The positive electrode of the light emitting diode D1 is connected with a direct current power supply V2, the negative electrode is connected with the collector c of the triode Q1 through a resistor R1, the base b of the triode Q1 is connected with the output end V1 of the driving circuit through a resistor R2, and the emission set e is grounded.
When the output end V1 of the driving circuit outputs high level, the triode Q1 is conducted, and the light-emitting diode D1 emits light; when the output end V1 of the driving circuit outputs low level, the transistor Q1 is turned off, and the light emitting diode D1 does not emit light. Resistor R2 may limit the current at the base b of transistor Q1 and resistor R1 may limit the current at the collector c of transistor Q1.
The photo-sensing module 20 includes a photodiode D2. The photodiode D2 can generate different current signals according to different light signals, and the region between the photodiode D2 and the light emitting diode D1 is a sensing region and can sense air particles. The size of air particles in the sensing area is different, and the photodiode D2 can generate different current signals; the photodiode D2 will produce different current signals as the concentration of airborne particles in the sensing region varies.
The signal amplification block 30 is a differential amplification circuit. The differential amplification circuit includes: an operational amplifier U1, an operational amplifier U2, an operational amplifier U3, a resistor R3 and a resistor R4; the positive phase input end of the operational amplifier U1 is connected with a direct-current power supply V2, the negative phase input end is connected with one end of a resistor R3, and the output end is connected with the other end of the resistor R3; one end of the resistor R3 is connected with the positive end of the photodiode D2, and the other end of the resistor R3 is connected with the negative phase input end of the operational amplifier U3; the negative electrode end of the photodiode D2 is respectively connected with one end of the resistor R4 and the negative phase input end of the operational amplifier U2; the positive phase input end of the operational amplifier U2 is connected with a direct current power supply V2, and the output end is connected with the other end of the resistor R4; the other end of the resistor R4 is also connected with the non-inverting input end of the operational amplifier U3; the output of the operational amplifier U3 is connected to the negative phase input and to the filtering module 40.
The current signal of the photodiode D2 may be amplified into a voltage signal by a differential amplification circuit. The voltage signal is typically a voltage pulse signal, the amplitude of which is indicative of the size of the air particles, and the number of which is indicative of the concentration of the air particles. The gain G output by the differential amplifier circuit is equal to the output terminal voltage of the operational amplifier U3/the sensing current of the photodiode D2 is equal to R7+ R10.
The filtering module 40 includes a first-order filtering unit 41 and a second-order filtering unit 42, and the first-order filtering unit 41 is connected with the second-order filtering unit 42; the first-order filtering unit 41 is connected with the signal amplifying module 30; the second-order filtering unit 42 is connected to the signal processing module 50.
The first-order filtering unit 41 includes: a capacitor C1, a capacitor C2, a resistor R5, a resistor R6, a resistor R7 and an operational amplifier U4; one end of the capacitor C1 is connected to the output end of the operational amplifier U3 of the signal amplification module 30, and the other end is connected to one end of the resistor winding and the non-inverting input end of the operational amplifier U4, respectively; the other end of the resistor R5 is grounded; the negative phase input end of the operational amplifier U4 is respectively connected with one end of a resistor R6, one end of a resistor R7 and one end of a capacitor C2, and the output end of the operational amplifier U4 is respectively connected with the other end of the resistor R7, the other end of the capacitor C2 and the second-order filtering unit 42; the other end of the resistor R6 is connected to ground.
The second-order filtering unit 42 includes: a capacitor C3, a capacitor C4, a resistor R8, a resistor R9, a resistor R10 and an operational amplifier U5; one end of the capacitor C3 is connected to the first-order filtering unit 41, and the other end is connected to one end of the resistor R8 and the non-inverting input terminal of the operational amplifier U5; the other end of the resistor R8 is grounded; the negative phase input end of the operational amplifier U5 is respectively connected with one end of the resistor R9, one end of the resistor R10 and one end of the capacitor C4, and the output end of the operational amplifier U5 is respectively connected with the other end of the resistor R10, the other end of the capacitor C4 and the signal processing module 50; the other end of the resistor R9 is connected to ground.
The low-frequency cutoff frequency of the first-order filtering unit 41 is Flow1 ═ 1/(2 pi × R11 × C14), the high-frequency cutoff frequency is Fhigh1 ═ 1/(2 pi × R5 × C8), and the gain is G1 ═ 1+ R5/R13.
The low-frequency cutoff frequency of the second-order filtering unit 42 is Flow2 ═ 1/(2 pi × R12 × C15), the high-frequency cutoff frequency is Fhigh2 ═ 1/(2 pi × R6 × C9), and the gain is G2 ═ 1+ R6/R14.
The low frequency cutoff values of the first order filtering unit 41 and the second order filtering unit 42 set the lower limit of the flow rate of the air particulate matter passing through the sensing region, the high frequency critical values of the first order filtering unit 41 and the second order filtering unit 42 set the upper limit of the flow rate of the air particulate matter passing through the sensing region, and the total gain of the first order filtering unit 41 and the second order filtering unit 42 is: the Gtot is (1+ R5/R13) × (1+ R6/R14), and interference in the voltage pulse signal can be filtered out through the processing of the first-order filtering unit 41 and the second-order filtering unit 42.
The signal processing module 50 includes a single chip microcomputer and a resistor R11. The resistor R11 can limit the input current of the singlechip. The single chip microcomputer can further perform signal processing on the voltage pulse signals of the second-order filtering unit 42, the size of the air particulate matters is detected by identifying the amplitude of the voltage pulse signals, and the concentration of the air particulate matters is detected by identifying the number of the voltage pulse signals in preset time.
According to the embodiment of the utility model, the sensing area is formed by the light emitting diode and the photodiode, the photodiode generates the induced current according to the air particulate matters in the sensing area, the differential amplification circuit converts the induced current into the voltage pulse signals, the amplitude of the voltage pulse signals represents the size of the air particulate matters, the number of the voltage pulse signals represents the concentration of the air particulate matters, and the voltage pulse signals are filtered by the filtering module and then processed by the singlechip, so that the size and the concentration of the air particulate matters can be detected.
It is to be noted that technical or scientific terms used herein shall have the ordinary meaning as understood by those skilled in the art to which embodiments of the present invention belong, unless otherwise specified.
In the description of the present embodiments, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate orientations and positional relationships that are based on the orientations and positional relationships shown in the drawings, and are used only for convenience in describing the embodiments of the present invention and for simplicity in description, but do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the embodiments of the present invention.
Furthermore, the technical terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description of the novel embodiments of the present invention, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "fixed" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral part; mechanical connection or electrical connection is also possible; either directly or indirectly through intervening media, either internally or in any other relationship. Specific meanings of the above terms in the embodiments of the present invention can be understood by those of ordinary skill in the art according to specific situations.
In describing the novel embodiments of this embodiment, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention, and they should be construed as being included in the following claims and description. In particular, the technical features mentioned in the embodiments can be combined in any way as long as there is no structural conflict. It is intended that the utility model not be limited to the particular embodiments disclosed, but that the utility model will include all embodiments falling within the scope of the appended claims.
Claims (9)
1. An airborne particle detection circuit, the circuit comprising: the device comprises a light emitting module, a light sensing module, a signal amplifying module, a filtering module and a signal processing module;
the light emitting module is used for generating a light signal;
the optical sensing module is used for receiving scattered light signals formed after the optical signals pass through the air particles and generating current signals according to the scattered light signals;
the signal amplification module is used for converting and amplifying the current signal into a voltage signal and transmitting the voltage signal to the filtering module;
the filtering module is used for filtering the voltage signal and transmitting the filtered voltage signal to the signal processing module;
the signal processing module is used for carrying out signal processing on the voltage signal after the filtering processing so as to generate an air particulate matter detection result;
the filtering module comprises a first-order filtering unit and a second-order filtering unit, and the first-order filtering unit is connected with the second-order filtering unit;
the first-order filtering unit is connected with the signal amplifying module;
the second-order filtering unit is connected with the signal processing module.
2. The airborne particle detection circuit of claim 1, wherein the light emitting module comprises: the light-emitting unit is connected with the switch unit;
the light-emitting unit comprises a positive terminal and a negative terminal;
the switch unit comprises an input end, a control end and an output end;
the positive end of the light-emitting unit is connected with a direct-current power supply, and the negative end of the light-emitting unit is connected with the input end of the switch unit;
the control end of the switch unit is connected with the drive circuit, and the output end of the switch unit is grounded.
3. The airborne particle detection circuit of claim 2, wherein the light emitting unit comprises a light emitting diode and the switching unit comprises a triode.
4. The airborne particle detection circuit of claim 1, wherein the light sensing module comprises a photodiode.
5. The airborne particle detection circuit of claim 4, wherein the signal amplification module comprises: the first operational amplifier, the second operational amplifier, the third resistor and the fourth resistor;
the positive phase input end of the first operational amplifier is connected with a direct current power supply, the negative phase input end of the first operational amplifier is connected with one end of the third resistor, and the output end of the first operational amplifier is connected with the other end of the third resistor;
one end of the third resistor is connected with the positive electrode end of the photodiode, and the other end of the third resistor is connected with the negative phase input end of the third operational amplifier;
the negative end of the photodiode is respectively connected with one end of the fourth resistor and the negative phase input end of the second operational amplifier;
the positive phase input end of the second operational amplifier is connected with the direct current power supply, and the output end of the second operational amplifier is connected with the other end of the fourth resistor;
the other end of the fourth resistor is also connected with a positive phase input end of the third operational amplifier;
and the output end of the third operational amplifier is connected with the negative phase input end and is connected with the filtering module.
6. The airborne particle detection circuit of claim 1, wherein the first order filtering unit comprises: the first capacitor, the second capacitor, the fifth resistor, the sixth resistor, the seventh resistor and the fourth operational amplifier;
one end of the first capacitor is connected with the signal amplification module, and the other end of the first capacitor is respectively connected with one end of the fifth resistor and the positive phase input end of the fourth operational amplifier;
the other end of the fifth resistor is grounded;
a negative phase input end of the fourth operational amplifier is respectively connected with one end of the sixth resistor, one end of the seventh resistor and one end of the second capacitor, and an output end of the fourth operational amplifier is respectively connected with the other end of the seventh resistor, the other end of the second capacitor and the second-order filtering unit;
the other end of the sixth resistor is grounded.
7. The air particulate matter detection circuit according to claim 1, wherein the second-order filter unit includes: a third capacitor, a fourth capacitor, an eighth resistor, a ninth resistor, a tenth resistor and a fifth operational amplifier;
one end of the third capacitor is connected with the first-order filtering unit, and the other end of the third capacitor is respectively connected with one end of the eighth resistor and the positive-phase input end of the fifth operational amplifier;
the other end of the eighth resistor is grounded;
a negative phase input end of the fifth operational amplifier is respectively connected with one end of the ninth resistor, one end of the tenth resistor and one end of the fourth capacitor, and an output end of the fifth operational amplifier is respectively connected with the other end of the tenth resistor, the other end of the fourth capacitor and the signal processing module;
the other end of the ninth resistor is grounded.
8. An airborne particle detector, characterized in that it comprises an airborne particle detection circuit according to any of claims 1 to 7.
9. An air purifier, characterized in that the air purifier comprises an air particulate matter detection circuit according to any one of claims 1 to 7.
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| CN202120220053.XU CN215574636U (en) | 2021-01-26 | 2021-01-26 | Air particulate matter detection circuit, air particulate matter detector and air purifier |
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