CN203025143U - Dew point measuring circuit based on lithium chloride humidity sensitive resistance - Google Patents
Dew point measuring circuit based on lithium chloride humidity sensitive resistance Download PDFInfo
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- CN203025143U CN203025143U CN 201220590923 CN201220590923U CN203025143U CN 203025143 U CN203025143 U CN 203025143U CN 201220590923 CN201220590923 CN 201220590923 CN 201220590923 U CN201220590923 U CN 201220590923U CN 203025143 U CN203025143 U CN 203025143U
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- resistance
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- lithium chloride
- dew point
- bridge
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Abstract
The utility model relates to a dew point measuring circuit based on lithium chloride humidity sensitive resistance. A lithium chloride humidity sensitive resistance sensor with a humidity measuring range of 0.4%RH-7%RH is taken as a measuring element; a bridge type oscillating circuit is used for carrying out alternating-current power supply; a signal is measured by an electric bridge after being amplified; and the accurate measurement of the signal is realized through an amplification circuit, a rectification circuit and a filtering display circuit. The dew point measuring circuit disclosed by the utility model is high in precision and sensitivity, can monitor a current humidity signal in real time, and can dispose of obvious humidity change in time so as to avoid damages to instruments and equipment caused by too high humidity.
Description
Technical field
The utility model relates to a kind of dew point measurement circuit based on the lithium chloride hygristor, belongs to environment measurement, field tests.
Background technology
In industry, agricultural production, meteorology, scientific research, national defence, all departments such as space flight often need to measure and monitor ambient humidity.But in common environmental parameter, humidity is one of parameter of the most difficult accurate measurement, measure humidity with methods such as hair hygrometer and psychrometers, can't satisfy the needs of modern development in science and technology already, this is more complicated than measuring temperature because measure humidity, temperature be one independently measured, but humidity is affected by a lot of other factors, such as atmospheric pressure, temperature etc.The standard of humidity is also a difficult problem in addition, and external humidity demarcating equipment price is extremely expensive.The measurement of the dew point in low wet environment, need especially it is carried out real-time online measuring, in order to avoid humidity is excessive, equipment is produced unnecessary damage, and in compressed environment, for the environment that relative humidity is 0.4%RH ~ 7%RH, the method of general measurement humidity is for precision, and sensitivity does not all reach requirement.
The utility model content
For solving the problems of the technologies described above, the purpose of this utility model is to provide a kind of dew point measurement circuit based on the lithium chloride hygristor, can carry out accurate real time and on line monitoring to the environment of this specific compression drying air.
The technical scheme that the utility model adopts is:
A kind of dew point measurement circuit based on the lithium chloride hygristor comprises bridge oscillator circuit 1, the first amplifying circuit 2, measuring bridge circuit 3, the second amplifying circuits 4, rectification circuit 5, filtering display circuit 6; The measuring sensor of described measuring bridge circuit 3 is lithium chloride resistive humidity sensor 27.
In aforesaid bridge oscillator circuit 1, electric capacity 1, resistance 1, electric capacity 2 23, resistance 29 is the connection in series-parallel frequency selection network, is connected to the homophase input and output side of operational amplifier 7, consists of positive feedback, produces self-sustained oscillation; Resistance 3 10, resistance 4 11 and resistance 5 12 are connected to reverse input end and the output terminal of operational amplifier 7, consist of negative feedback; Two diodes 25 are parallel to resistance 5 12.
Aforesaid the first amplifying circuit 2 comprises an operational amplifier 7, and resistance 6 13 and resistance 7 14 are connected to its input and output side.
In aforesaid measuring bridge circuit 3, resistance 8 15, resistance 9 16, resistance 10 connection in series-parallel form electric bridge in the two ends of lithium chloride resistive humidity sensor 27 and measure.
Aforesaid the second amplifying circuit 4 comprises an operational amplifier 7, and resistance 11 and resistance 12 are connected to its input and output side.
In aforesaid filtering display circuit 6, be serially connected with a resistance 13, electric capacity 3 24 and resistance 14 are parallel to the output terminal of rectification circuit, use as filtering, show by D.C. voltmeter 26 at last.
By technique scheme, the beneficial effects of the utility model are:
(1) adopt the lithium chloride resistive humidity sensor, when measuring temperature and be 26 ° of C ~ 50 ° C scope, the resistance variations scope is 110K Ω ~ 50M Ω, range of humidity variation is 0.4%RH ~ 7%RH, measuring accuracy is high, and sensitivity is good, is particularly suitable for the dew point measurement of low humidity industrial environment.
(2) size that can the on line real-time monitoring dew point is in time found the variation of dew point, and can in time be made feedback, avoids because humidity is excessive, equipment being caused unnecessary damage.
Description of drawings
The utility model is described in further detail below in conjunction with drawings and Examples;
Fig. 1 is that the utility model is based on the dew point measurement circuit diagram of lithium chloride hygristor.
Embodiment
Be to reach the technological means that the expection purpose is taked for further setting forth the utility model, below in conjunction with drawings and the specific embodiments, the utility model be described in detail.
As shown in Figure 1, the dew point measurement circuit based on the lithium chloride hygristor that the utility model proposes comprises bridge oscillator circuit 1, the first amplifying circuit 2, measuring bridge circuit 3, the second amplifying circuits 4, rectification circuit 5 and filtering display circuit 6; In bridge oscillator circuit 1, electric capacity 1, resistance 1, electric capacity 2 23, resistance 29 is the connection in series-parallel frequency selection network, is connected to the homophase input and output side of operational amplifier 7, consists of positive feedback, produces self-sustained oscillation, with this, measuring sensor is carried out Alternating Current Power Supply; Resistance 3 10, resistance 4 11 and resistance 5 12 are connected to reverse input end and the output terminal of operational amplifier 7, consist of negative feedback; Two diodes 25 are parallel to resistance 5 12, play the gain of automatic adjustment negative feedback amplifier circuit, keep the stable effect of output voltage amplitude; The first amplifying circuit 2 comprises an operational amplifier 7, and resistance 6 13 and resistance 7 14 are connected to its input and output side, is used for amplifying the voltage that bridge oscillator circuit 1 produces, and drives the needed voltage of measuring sensor work thereby satisfy; In measuring bridge circuit 3, adopt lithium chloride resistive humidity sensor 27 as measuring sensor, resistance 8 15, resistance 9 16, resistance 10 connection in series-parallel like this, just can convert the resistance change rate of resistor disc to Voltage-output in its two ends; The second amplifying circuit 4 comprises an operational amplifier 7, and resistance 11 and resistance 12 are connected to its input and output side, is used for the voltage of measurement by magnification bridge diagram 3 outputs; Rectification circuit 5 consists of bridge rectifier circuit by four diodes 25, and like this, the AC signal that just will export after bridge measurement is converted to direct current signal; At last, in filtering display circuit 6, be connected in series a resistance 13, electric capacity 3 24 and resistance 14 are parallel to the output terminal of rectification circuit 5, and the ripple in the elimination rectifier output voltage shows by D.C. voltmeter 26 at last.
As preferred version, the operational amplifier in the present embodiment adopts chip OP07, and diode is IN4148, and the parameter value of each element is referring to table 1.
The corresponding table of table 1 device parameter values
| The element title | Resistance one | Resistance two | Resistance three | Resistance four | Resistance five | Resistance six | Resistance seven | Resistance eight | Resistance nine |
| Parameter value | 3KΩ | 3KΩ | 2KΩ | 3KΩ | 10KΩ | 100Ω | 1KΩ | 22K?Ω | 22KΩ |
| The element title | Resistance ten | |
|
|
|
Electric capacity one | Electric capacity two | Electric capacity three | ? |
| Parameter value | 22KΩ | 100KΩ | 100KΩ | 1KΩ | 1KΩ | 1μF | 1μF | 10μF | ? |
The supply voltage that the lithium chloride resistive humidity sensor requires is the alternating current of 5 ~ 10V, the supply voltage of operational amplifier OP07 is+12V and-12V, so the oscillating voltage that bridge oscillator circuit produces needs to amplify through the first amplifying circuit, could drive the work of lithium chloride resistive humidity sensor, then the change in resistance of its resistance is voltage signal through the measuring bridge circuit conversion, this voltage signal is after the second amplifying circuit amplifies, again via rectification circuit, be converted into direct current signal, through filtering, show by D.C. voltmeter at last, realized the Real Time Monitoring to dew point.
It is more than further detailed description of the utility model in conjunction with specific embodiments.The technician of the industry should understand; the utility model is not restricted to the described embodiments; without departing from the concept of the premise utility, can also make some changes or replacement, these changes or replacement all fall in claimed the utility model scope.The utility model protection domain is defined by appending claims and equivalent thereof.
Claims (4)
1. the dew point measurement circuit based on the lithium chloride hygristor, is characterized in that: comprise bridge oscillator circuit (1), the first amplifying circuit (2), measuring bridge circuit (3), the second amplifying circuit (4), rectification circuit (5), filtering display circuit (6); The measuring sensor of described measuring bridge circuit (3) is lithium chloride resistive humidity sensor (27); In described bridge oscillator circuit (1), electric capacity one (22), resistance one (8), electric capacity two (23), resistance two (9) is the connection in series-parallel frequency selection network, is connected to the homophase input and output side of operational amplifier (7), consists of positive feedback, produces self-sustained oscillation; Resistance three (10), resistance four (11) and resistance five (12) are connected to reverse input end and the output terminal of operational amplifier (7), consist of negative feedback; Two diodes (25) are parallel to resistance five (12); In described measuring bridge circuit (3), resistance eight (15), resistance nine (16), resistance ten (17) connection in series-parallel are in the two ends of lithium chloride resistive humidity sensor (27), and three resistance and sensor consist of bridge measuring circuit; In described filtering display circuit (6), be connected in series a resistance ten three (20), electric capacity three (24) and resistance ten four (21) are parallel to the output terminal of rectification circuit, show by D.C. voltmeter (26) at last.
2. a kind of dew point measurement circuit based on the lithium chloride hygristor according to claim 1, it is characterized in that, described the first amplifying circuit (2) comprises an operational amplifier (7), and resistance six (13) and resistance seven (14) are connected to its input and output side.
3. a kind of dew point measurement circuit based on the lithium chloride hygristor according to claim 1, it is characterized in that, described the second amplifying circuit (4) comprises an operational amplifier (7), and resistance ten one (18) and resistance ten two (19) are connected to its input and output side.
4. a kind of dew point measurement circuit based on the lithium chloride hygristor according to claim 1, is characterized in that, described rectification circuit (5) consists of bridge rectifier circuit by four diodes (25).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220590923 CN203025143U (en) | 2012-11-09 | 2012-11-09 | Dew point measuring circuit based on lithium chloride humidity sensitive resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220590923 CN203025143U (en) | 2012-11-09 | 2012-11-09 | Dew point measuring circuit based on lithium chloride humidity sensitive resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203025143U true CN203025143U (en) | 2013-06-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220590923 Expired - Fee Related CN203025143U (en) | 2012-11-09 | 2012-11-09 | Dew point measuring circuit based on lithium chloride humidity sensitive resistance |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203025143U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111998895A (en) * | 2020-08-26 | 2020-11-27 | 广东电网有限责任公司广州供电局 | Humidity monitoring method and device |
-
2012
- 2012-11-09 CN CN 201220590923 patent/CN203025143U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111998895A (en) * | 2020-08-26 | 2020-11-27 | 广东电网有限责任公司广州供电局 | Humidity monitoring method and device |
| CN111998895B (en) * | 2020-08-26 | 2022-07-08 | 广东电网有限责任公司广州供电局 | Humidity monitoring method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130626 Termination date: 20131109 |