CN101701857B - Sensor circuit used for sensitive element of conductive composite material - Google Patents
Sensor circuit used for sensitive element of conductive composite material Download PDFInfo
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- CN101701857B CN101701857B CN2009102372949A CN200910237294A CN101701857B CN 101701857 B CN101701857 B CN 101701857B CN 2009102372949 A CN2009102372949 A CN 2009102372949A CN 200910237294 A CN200910237294 A CN 200910237294A CN 101701857 B CN101701857 B CN 101701857B
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Abstract
The invention relates to a sensor circuit used for a sensitive element of a conductive composite material, which belongs to the technical field of sensors. The sensor circuit comprises an alternating-current signal excitation source, a signal pickup circuit and a detection circuit which are connected sequentially, wherein the alternating-current signal source is used for generating an alternating-current excitation signal and supplying the alternating-current excitation signal to the signal pickup circuit; the signal pickup circuit is used for completing resistance-voltage transformation, outputting a signal with the amplitude value in proportion with the impedance of the sensitive element and the frequency the same as the output frequency of the alternating-current signal source and then supplying the signal to the detection circuit; and the detection circuit is used for completing the transformation from an alternating-current signal to a direct-current signal, extracting the single-side envelope of the alternating-current signal and outputting the direct-current signal in direct proportion with the impedance of the sensitive element. The invention can realize small null shift, good repeatability and high temperature stability and is widely suitable for various sensors based on the conductive composite material.
Description
Technical field
The invention belongs to sensor technical field, particularly based on the Design of Sensor of conducing composite material.
Background technology
Conducing composite material with its pressure-sensitive character, draw character such as quick characteristic, gas-sensitive property and obtain broad research and application in sensor field, all is to adopt DC excitation as U.S. Tekscan company and the production of Interlink Elctronics company based on the conducing composite material pressure sensor circuit, the said firm uses above-mentioned sensor circuit based on the conducing composite material pressure-sensing device as shown in Figure 1, by dc signal source V
T, conducing composite material pressure-sensing device (resistance) Rs, operational amplifier and feedback resistance Rf thereof constitute the sensor circuit based on negative-feedback circuit, output voltage V o=-(R
f/ R
s) V
T
Because the inherent characteristic of conducing composite material causes its dc resistance to have bigger drift, and then cause having big drift based on the sensor of above-mentioned continuous-current excitation circuit; Conducing composite material has the responsive to temperature characteristic, and then causes existing big temperature to float based on the sensor of above-mentioned continuous-current excitation circuit; Conductive composite material resistance has bigger viscous-elastic behaviour, causes repeated relatively poor based on the sensor of above-mentioned continuous-current excitation circuit.
Summary of the invention
The objective of the invention is for overcoming the weak point of continuous-current excitation, a kind of sensor circuit that is used for sensitive element of conductive composite material is proposed, simple, energy-conservation, low drift that sensor circuit of the present invention has, low temperature float, the characteristics of good reproducibility, are suitable for various sensors based on sensitive element of conductive composite material.
The sensor circuit that the present invention proposes based on sensitive element of conductive composite material, it is characterized in that this sensor circuit comprises ac-excited source, signal pickup circuit and the detecting circuit that links to each other successively, wherein, ac signal which, the pumping signal that is used to produce interchange offers signal pickup circuit; Signal pickup circuit is used to finish resistance-voltage transitions, and the signal daytime that output amplitude is proportional with the sensitive element impedance, frequency is identical with the ac signal which output frequency offers detecting circuit; Detecting circuit is used to finish the conversion of AC signal to direct current signal, extracts the monolateral envelope of AC signal, the direct current signal that output is directly proportional with the sensitive element impedance.
Described AC signal driving source is the sine wave of 10kHz-1MHz, and the amplitude of ac-excited signal is 1-5V.
Characteristics of the present invention and effect:
The present invention is directed to based on the sensor sensing element of conducing composite material and adopt the AC signal excitation, with respect to continuous-current excitation, make that this type of sensor has that drift is little, good reproducibility, characteristics that temperature stability is high.
Description of drawings
Fig. 1 is the sensor circuit schematic diagram of Tekscan company.
Fig. 2 is the enforcement circuit theory diagrams of sensor circuit of the present invention.
Embodiment
The sensitive element of conductive composite material sensor circuit that is used for that the present invention proposes is described in detail as follows in conjunction with the embodiments:
The sensor circuit that is used for sensitive element of conductive composite material that the present invention proposes, it is characterized in that this sensor circuit comprises ac-excited source, signal pickup circuit and the detecting circuit that links to each other successively, wherein, ac signal which, the pumping signal that is used to produce interchange offers signal pickup circuit; Signal pickup circuit is used to finish resistance-voltage transitions, and the signal that output amplitude is proportional with the sensitive element impedance, frequency is identical with the ac signal which output frequency offers detecting circuit then; Detecting circuit is used to finish the conversion of AC signal to direct current signal, extracts the monolateral envelope of AC signal, the direct current signal (Rp is used for regulating output voltage) that output is directly proportional with the sensitive element impedance.
Embodiment of the invention circuit, as shown in Figure 2, the composition of part each several part is not mentionleted alone bright as follows:
1. ac signal which: the frequency of the ac-excited signal that the ac signal which of present embodiment produces is 10kHz-1MHz, amplitude is the sine wave of 1-5V, adopt existing function signal generator, AFG3201 function generator as Tektronix company, also can adopt special-purpose waveform generator chip, as MAX038.
2. signal pickup circuit: the signal pickup circuit of present embodiment by amplifier (as AD744, LM158 etc., bandwidth is greater than 1MHz), sensitive element Rs and build-out resistor Rf and Ri form, wherein, first end of build-out resistor Rf links to each other with first end of ac signal which, and second end links to each other with the first input end of amplifier; First end of build-out resistor Ri links to each other with second end of ac signal which, and second end links to each other with second input end of amplifier; Sensitive element Rs is connected across between the output terminal of second end of build-out resistor Rf and amplifier.
3. detecting circuit: the filter network formation that the detecting circuit of present embodiment is made up of detector diode D1 (as adopting 2AP9, CTL22S etc.) and resistance R d, variable resistor RP, capacitor C 1, C2, wherein, the input end of the amplifier of the input of detector diode D1 and signal pickup circuit; The output terminal of detector diode D1 links to each other with the input end of resistance R d; Capacitor C 1 is connected across between second end of the input end of resistance R d and ac signal which; Between the output terminal that is connected across resistance R d of capacitor C 2 and second end of ac signal which, the input end of variable resistor Rp links to each other with the output terminal of resistance R d, the output terminal of variable resistor Rp links to each other with second end of ac signal which and constitutes an output terminal of whole sensor circuit, and the sliding tap end of variable resistor RP is another output terminal of whole sensor circuit.
The present invention can reach excellent performance index:
Sensor circuit of the present invention can reduce by two with this type of existing sensor drift to be eliminated temperature substantially and floats more than the order of magnitude, improves the repeatability of sensor greatly.
Claims (2)
1. sensor circuit that is used for sensitive element of conductive composite material, it is characterized in that this sensor circuit comprises ac-excited source, signal pickup circuit and the detecting circuit that links to each other successively, wherein, ac-excited source, the pumping signal that is used to produce interchange offers signal pickup circuit; Signal pickup circuit is used to finish resistance-voltage transitions, and the signal that output amplitude is proportional with the sensitive element impedance, frequency is identical with the ac signal which output frequency offers detecting circuit then; Detecting circuit is used to finish the conversion of AC signal to direct current signal, extracts the monolateral envelope of AC signal, the direct current signal that output is directly proportional with the sensitive element impedance.
2. sensor circuit as claimed in claim 1 is characterized in that, described ac-excited source is the sine wave of 10kHz-1MHz, and the amplitude of ac-excited signal is 1-5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009102372949A CN101701857B (en) | 2009-11-06 | 2009-11-06 | Sensor circuit used for sensitive element of conductive composite material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009102372949A CN101701857B (en) | 2009-11-06 | 2009-11-06 | Sensor circuit used for sensitive element of conductive composite material |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101701857A CN101701857A (en) | 2010-05-05 |
| CN101701857B true CN101701857B (en) | 2011-02-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
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| CN2009102372949A Expired - Fee Related CN101701857B (en) | 2009-11-06 | 2009-11-06 | Sensor circuit used for sensitive element of conductive composite material |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1877998A (en) * | 2006-06-23 | 2006-12-13 | 北京航空航天大学 | Digital phase-locking loop for resistance vibration-pickup type silicon micro-mechanical resonate sensor |
| CN101458221A (en) * | 2008-12-26 | 2009-06-17 | 无锡尚沃生物科技有限公司 | Metallic oxide/carbon nanotube gas sensors |
-
2009
- 2009-11-06 CN CN2009102372949A patent/CN101701857B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1877998A (en) * | 2006-06-23 | 2006-12-13 | 北京航空航天大学 | Digital phase-locking loop for resistance vibration-pickup type silicon micro-mechanical resonate sensor |
| CN101458221A (en) * | 2008-12-26 | 2009-06-17 | 无锡尚沃生物科技有限公司 | Metallic oxide/carbon nanotube gas sensors |
Non-Patent Citations (2)
| Title |
|---|
| JP特开2001-174428A 2001.06.29 |
| 王鹏,丁天怀,徐峰,覃元臻.炭黑_硅橡胶复合材料的压阻特性研究与改进.《传感技术学报》.2004,15-18. * |
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| CN101701857A (en) | 2010-05-05 |
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Granted publication date: 20110216 Termination date: 20121106 |