CN203870058U - Humidity detection circuit with self-detection function - Google Patents
Humidity detection circuit with self-detection function Download PDFInfo
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- CN203870058U CN203870058U CN201420136792.0U CN201420136792U CN203870058U CN 203870058 U CN203870058 U CN 203870058U CN 201420136792 U CN201420136792 U CN 201420136792U CN 203870058 U CN203870058 U CN 203870058U
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Abstract
The utility model discloses a humidity detection circuit with a self-detection function, the humidity detection circuit comprises a CMOS (complementary metal oxide semiconductor) timer, a resistor R1, a resistor R2, a resistor R3, a resistor R4, an adjustable capacitor C, an alternating current power supply, a light emitting diode D1, a light emitting diode D2, a light emitting diode D3 and a light emitting diode D4, wherein an output port TR of the CMOS timer is sequentially connected with the light emitting diode D1, the resistor R2, the resistor R3 and the alternating current power supply in series; an output port CO of the CMOS timer is sequentially connected with the light emitting diode D2, the resistor R1 and a ground terminal in series; an output port TH of the CMOS timer is sequentially connected with the light emitting diode D3, the adjustable capacitor C and the ground terminal in series; a power port VCC and an output port R of the CMOS timer are connected with the alternating current power supply; an output port D of the CMOS timer is connected with a common port of the resistor R2 and the resistor R3; and an output port out of the CMOS timer is sequentially connected with the light emitting diode D4, the resistor R4 and an output port Vout in series. By means of the principle, the humidity detection circuit with the self-detection function is high in circuit reliability, good in stability, short in reaction time and simple and convenient to use, and can judge whether the ports in the timer work normally through the light emitting diodes.
Description
Technical field
The utility model relates to humidity measuring circuit, is specifically related to have the humidity measuring circuit of self-checking function.
Background technology
The mankind's existence and social activities and humidity are closely related.Along with modern realization, be difficult to find out one and come with the irrelevant field of humidity.Because application is different, also different to the technical requirement of humidity sensor.From manufacturing angle, be both humidity sensor, material, structure difference, technique is different. and its performance and technical indicator have very big-difference, thereby price also differs greatly.Concerning user, while selecting humidity sensor, first to make clear and need which type of sensor; The financial resources of oneself allow to choose the product of what class, weigh the relation of " requirements and potentialities ", are unlikely to blindly to act.With measure weight, temperature is the same, selects humidity sensor first will determine measurement range.In departments such as industrial and agricultural production, meteorology, environmental protection, national defence, scientific research, space flight, often need to ambient humidity be measured and be controlled.But in conventional environmental parameter, humidity is a parameter of difficult Measurement accuracy.With psychrometer or hair hygrometer, measure the method for humidity, cannot meet already the needs of modern development in science and technology.This is that temperature is individual independently measured because measure humidity than measuring the many of temperature complexity, and humidity is subject to the impact of other factors (atmospheric pressure, temperature).In addition, the standard of humidity is also a difficult problem.The external humidity demarcating equipment price of producing is very expensive.Existing humidity sensor reliability is low, poor stability, reaction time slow and timer on port whether normally work and cannot judge.
Utility model content
The utility model has overcome the deficiencies in the prior art, the humidity measuring circuit with self-checking function is provided, this circuit reliability is high, good stability, reaction time fast and can judge whether the individual port on timer normally works by light emitting diode, easy to use.
For solving above-mentioned technical matters, the utility model is by the following technical solutions: the humidity measuring circuit with self-checking function, comprise CMOS timer, resistance R 1, resistance R 2, resistance R 3, resistance R 4, tunable capacitor C, AC power, light emitting diode D1, light emitting diode D2, light emitting diode D3 and light emitting diode D4, the output port TR of described CMOS timer connect successively light emitting diode D1, resistance R 2, resistance R 3 and AC power; The output port CO of CMOS timer connect successively light emitting diode D2, resistance R 1 and earth terminal; The output port TH of CMOS timer connect successively light emitting diode D3, tunable capacitor C and earth terminal; The power port VCC of CMOS timer is all connected AC power with output port R, the output port D contact resistance R2 of CMOS timer and the common port of resistance R 3, the output port out of CMOS timer connect successively light emitting diode D4, resistance R 4 and output port Vout.Light emitting diode D1 wherein, light emitting diode D2, light emitting diode D3 and light emitting diode D4 are the semiconductor electronic original paper that can glow, whether the lattice port mainly as indication CMOS timer normally works, and conventional light emitting diode can be satisfied the demand now.Tunable capacitor C is wherein air tunable capacitor, and its medium is air, and the size that only need allow distance, relative position or the area of two-plate can change electric capacity is very suitable for ambient temperature and humidity and detects.
Described CMOS timer is 7556 timers.This timer is dual timer, supply voltage scope is between+3V-+18V, the maximum current of output can reach 200mA, only need connect a small amount of capacitance-resistance original paper and can form monostable, multi resonant and Schmidt trigger, is very suitable for generation, conversion, control and the detection of signal.The circuit reliability forming with this timer is good, and stability is high.
The Standard resistance range of described resistance R 1 is between 850-930 kilo-ohm.The resistance of R2 is 580 kilo-ohms of left and right.
The scope of described alternating voltage is between 3-12V.
The resistance size of described resistance R 3 is 50 times of resistance R 4 resistances.Wherein the resistance of R3 is 1 kilo-ohm of left and right, and the resistance of resistance R 4 all can 50 kilo-ohms of left and right.
Compared with prior art, the beneficial effects of the utility model are:
1, the utility model adopts 7556 timers, and better effects if is regularly utilized the circuit of tunable capacitor and resistance R 2, R3 composition, converts relative humidity to frequency signal, this circuit reliability is high, good stability and the reaction time fast.
2, on a plurality of ports of CMOS timer, light emitting diode is all set whether normal for detection of each port working, guarantees to measure the accurate of humidity, reduce measuring error.
Accompanying drawing explanation
Fig. 1 is circuit diagram of the present utility model.
Embodiment
Below in conjunction with accompanying drawing, the utility model is further elaborated, embodiment of the present utility model is not limited to this.
Embodiment:
As shown in Figure 1, the utility model comprises CMOS timer, resistance R 1, resistance R 2, resistance R 3, resistance R 4, tunable capacitor C, AC power, light emitting diode D1, light emitting diode D2, light emitting diode D3 and light emitting diode D4, CMOS timer is 7556 timers, the Standard resistance range of resistance R 1 is between 850-930 kilo-ohm, the scope of alternating voltage is between 3-12V, and the resistance size of resistance R 3 is 50 times of resistance R 4 resistances.This timer is dual timer, supply voltage scope is between+3V-+18V, the maximum current of output can reach 200mA, only need connect a small amount of capacitance-resistance original paper and can form monostable, multi resonant and Schmidt trigger, is very suitable for generation, conversion, control and the detection of signal.The resistance of R2 is 580 kilo-ohms of left and right.
The output port TR of the CMOS timer of the present embodiment connect successively light emitting diode D1, resistance R 2, resistance R 3 and AC power; The output port CO of CMOS timer connect successively light emitting diode D2, resistance R 1 and earth terminal; The output port TH of CMOS timer connect successively light emitting diode D3, tunable capacitor C and earth terminal; The power port VCC of CMOS timer is all connected AC power with output port R, the output port D contact resistance R2 of CMOS timer and the common port of resistance R 3, the output port out of CMOS timer connect successively light emitting diode D4, resistance R 4 and output port Vout.
This circuit is placed in environment to be detected, by connecting tunable capacitor C, resistance R 2 and resistance R 3 on 7556 timers, form monostable circuit as shown in the figure, under the effect of extraneous trigger pulse, circuit is turned to transient state from stable state, after maintaining a period of time, transient state returns to again stable state, and produce a rect.p. at output terminal, convert the relative humidity in environment to be measured to frequency signal, by the frequency signal of delivery outlet Vout output 6000-7500Hz, this output signal outputs to frequency meter or single-chip microcomputer can demonstrate rh value.R4, as the current-limiting resistance of output terminal, shields.In addition, on a plurality of ports of 7556 timers, be all connected to light emitting diode, whether working properly for detection of 7556 timer upper port, to reduce the error of Humidity Detection, guarantee the correct of Humidity Detection.This circuit reliability is high, good stability and the reaction time fast.
Just can realize this utility model as mentioned above.
Claims (5)
1. the humidity measuring circuit with self-checking function, it is characterized in that: comprise CMOS timer, resistance R 1, resistance R 2, resistance R 3, resistance R 4, tunable capacitor C, AC power, light emitting diode D1, light emitting diode D2, light emitting diode D3 and light emitting diode D4, the output port TR of described CMOS timer connect successively light emitting diode D1, resistance R 2, resistance R 3 and AC power; The output port CO of CMOS timer connect successively light emitting diode D2, resistance R 1 and earth terminal; The output port TH of CMOS timer connect successively light emitting diode D3, tunable capacitor C and earth terminal; The power port VCC of CMOS timer is all connected AC power with output port R, the output port D contact resistance R2 of CMOS timer and the common port of resistance R 3, the output port out of CMOS timer connect successively light emitting diode D4, resistance R 4 and output port Vout.
2. the humidity measuring circuit with self-checking function according to claim 1, is characterized in that: described CMOS timer is 7556 timers.
3. the humidity measuring circuit with self-checking function according to claim 1, is characterized in that: the Standard resistance range of described resistance R 1 is between 850-930 kilo-ohm.
4. the humidity measuring circuit with self-checking function according to claim 1, is characterized in that: the scope of described alternating voltage is between 3-12V.
5. the humidity measuring circuit with self-checking function according to claim 1, is characterized in that: the resistance size of described resistance R 3 is 50 times of resistance R 4 resistances.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420136792.0U CN203870058U (en) | 2014-03-25 | 2014-03-25 | Humidity detection circuit with self-detection function |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420136792.0U CN203870058U (en) | 2014-03-25 | 2014-03-25 | Humidity detection circuit with self-detection function |
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| Publication Number | Publication Date |
|---|---|
| CN203870058U true CN203870058U (en) | 2014-10-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201420136792.0U Expired - Fee Related CN203870058U (en) | 2014-03-25 | 2014-03-25 | Humidity detection circuit with self-detection function |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103868953A (en) * | 2014-03-25 | 2014-06-18 | 成都国科海博信息技术股份有限公司 | Humidity detection circuit with high reliability |
-
2014
- 2014-03-25 CN CN201420136792.0U patent/CN203870058U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103868953A (en) * | 2014-03-25 | 2014-06-18 | 成都国科海博信息技术股份有限公司 | Humidity detection circuit with high reliability |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| 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: 20141008 Termination date: 20200325 |