CN204740293U - Capacitive sensor circuit - Google Patents
Capacitive sensor circuit Download PDFInfo
- Publication number
- CN204740293U CN204740293U CN201520296701.4U CN201520296701U CN204740293U CN 204740293 U CN204740293 U CN 204740293U CN 201520296701 U CN201520296701 U CN 201520296701U CN 204740293 U CN204740293 U CN 204740293U
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- triode
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- compensator
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Abstract
The utility model discloses a capacitive sensor circuit wherein, uses two -stage triode amplifier circuit, and first order circuit comprises resistance R1, R2, triode T1, R1's the one end VCC that connects wherein, and triode T1's collecting electrode is connected to the other end, and triode T1's projecting pole is connected to resistance R2's one end, and the other end is connected to refers to ground, detects the base that the utmost point was connected to triode T1, second level circuit comprises triode T2 and resistance R4, and triode T2's collecting electrode links to each other with power VCC, and the base is connected to triode T1's collecting electrode, and the projecting pole links to each other with resistance R4's one end, and resistance R4's the other end with linking to each other with referring to. The utility model provides a pair of capacitive sensor circuit compared with former RC oscillator, had the detectivity height, the reliable and stable advantage of circuit.
Description
Technical field
The utility model relates to a kind of sensor circuit, particularly relates to a kind of capacitive transducer realizing circuit.
Background technology
Capacitive transducer may be used for the measurements such as thing position, material level, liquid level, shift length.Existing capacitive transducer, generally by resistance-capacitance oscillator, single-chip microcomputer and special chip three kinds of mode practical functions.Though general resistance-capacitance oscillator has the simple advantage of structure, its less stable, can only the larger change of Detection capacitance amount, its sensitivity is also poor in addition.And not high by microprocessor detect detection sensitivity, special chip price comparison is high.For the above-mentioned defect that capacitive transducer in prior art exists, the utility model proposes a kind of capacitive transducer realizing circuit.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of capacitive transducer realizing circuit, compares, have detection sensitivity high with existing resistance-capacitance oscillator, the reliable advantage of circuit stability.
The utility model is solve the problems of the technologies described above the technical scheme adopted to be to provide a kind of capacitive transducer realizing circuit, use two-stage transistor amplifier, first order electricity routing resistance R1, R2, triode T1 are formed, wherein one end of R1 connects power supply VCC, the collector of other end connecting triode T1, the emitter of one end connecting triode T1 of resistance R2, the other end is connected to reference to ground, detects the base stage that pole is connected to triode T1;
Second level circuit is made up of triode T2 and resistance R4, and the collector of triode T2 is connected with power supply VCC, and base stage is connected to the collector of triode T1, and emitter is connected with one end of resistance R4, and the other end of resistance R4 is connected with reference to ground;
Resistance R3 is the biasing resistor of first order circuit triode T1, and one end of resistance R3 follows the emitter of triode T2 to be connected, and the other end is connected with the base stage of triode T1;
Also comprise electric capacity C1, its one end is connected with the emitter of triode T2, and the other end is connected with the emitter of triode T1.
Above-mentioned a kind of capacitive transducer realizing circuit, wherein, second level circuit also comprises thermo-compensator NTC2, and the emitter of triode T2 follows one end of thermo-compensator NTC2 to be connected, and the other end of thermo-compensator NTC2 is connected with one end of resistance R4.
Above-mentioned a kind of capacitive transducer realizing circuit, wherein, also comprise a back electrode, back electrode is connected with triode T2.
The utility model has following beneficial effect relative to prior art:
A kind of capacitive transducer realizing circuit that the utility model provides, compare with existing resistance-capacitance oscillator, there is detection sensitivity high, the reliable advantage of circuit stability, by the parameter of rational regulating circuit, namely can realize the sensitivity that overlength distance detects, also can realize the resolution closely detected, the high linearity under certain detecting distance can also be realized.
Accompanying drawing explanation
Fig. 1 is the circuit diagram of this patent;
Fig. 2 is the another kind of circuit diagram that capacitive transducer realizes identical function.
Embodiment
Below in conjunction with drawings and Examples, the utility model will be further described.
The circuit that this patent provides uses two-stage transistor amplifier, first order electricity routing resistance R1, R2, triode T1 are formed, wherein one end of R1 connects power supply VCC, the collector of other end connecting triode T1, the emitter of one end connecting triode T1 of resistance R2, the other end is connected to reference to ground, detects the base stage that pole is connected to triode T1.
Second level circuit is made up of triode T2 and resistance R4 and optional thermo-compensator NTC2, the collector of triode T2 is connected with power supply VCC, base stage is connected to the collector of triode T1, emitter is connected with one end of optional thermo-compensator NTC2, the other end of thermo-compensator NTC2 is connected with one end of resistance R4, the other end of resistance R4 with reference to be connected.
Resistance R3 and optional thermo-compensator NTC1 is the biasing resistor of first order circuit T1, one end of resistance R3 is connected with the emitter of triode T2, the other end is connected with one end of optional thermo-compensator NTC1, the other end of thermo-compensator NTC1 is connected with the base stage of triode T1, is improved circuit stability effect as negative voltage feedback.
Electric capacity C1 is the primary feedback electric capacity of circuit, and its one end is connected with the emitter of triode T2, and the other end is connected with the emitter of triode T1, by the feedback factor regulating C1 can change circuit, thus obtains reliable and stable concussion.An optional back electrode is connected with triode T2, as introduced back electrode, can improve directive property and the sensitivity of sensor.
The emitter of triode T2, as the output of this circuit, can obtain with testing capacitance change and the frequency of change and range signal.Just capacitance now to be measured can be known by detection frequency or power supply.
By to introduce and to select suitable optional thermo-compensator NTC1, NTC2 that circuit can be made to export under different temperature conditions basicly stable, reduce the temperature drift of circuit, be conducive to improving the operating temperature range of the sensitivity of circuit, resolution, signal to noise ratio (S/N ratio), the linearity, stability, reliability and circuit.
As shown in Figure 2, triode T1, triode T2 that the circuit diagram that this patent provides can use operational amplifier to come in replacement circuit, to improve stability and the reliability of circuit further.Its connected mode is as accompanying drawing 2, and its output OA detecting pole concatenation operation amplifier IC holds, and the inverting input of back electrode concatenation operation amplifier.Here R1 is negative feedback resistor, can regulate the enlargement factor of whole circuit, and improves the stability of circuit, in order to improve the stability of circuit further, uses a crystal oscillator or ceramic resonator to carry out the electric capacity C1 of alternative transistor circuit here.Such circuit output frequency stabilization is fallen and shake amplitude with Detection capacitance change and change AC signal.Because its frequency is more stable, can further improve the EMC performance of circuit.This circuit is applicable to the occasion of high reliability, low EMI.
Claims (3)
1. a capacitive transducer realizing circuit, is characterized in that:
Use two-stage transistor amplifier, first order electricity routing resistance R1, R2, triode T1 are formed, wherein one end of R1 connects power supply VCC, the collector of other end connecting triode T1, the emitter of one end connecting triode T1 of resistance R2, the other end is connected to reference to ground, detects the base stage that pole is connected to triode T1;
Second level circuit is made up of triode T2 and resistance R4, and the collector of triode T2 is connected with power supply VCC, and base stage is connected to the collector of triode T1, and emitter is connected with one end of resistance R4, and the other end of resistance R4 is connected with reference to ground;
Resistance R3 is the biasing resistor of first order circuit triode T1, and one end of resistance R3 follows the emitter of triode T2 to be connected, and the other end is connected with the base stage of triode T1;
Also comprise electric capacity C1, its one end is connected with the emitter of triode T2, and the other end is connected with the emitter of triode T1.
2. a kind of capacitive transducer realizing circuit as claimed in claim 1, it is characterized in that: second level circuit also comprises thermo-compensator NTC2, the emitter of triode T2 follows one end of thermo-compensator NTC2 to be connected, and the other end of thermo-compensator NTC2 is connected with one end of resistance R4.
3. a kind of capacitive transducer realizing circuit as claimed in claim 2, is characterized in that: also comprise a back electrode, back electrode is connected with triode T2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520296701.4U CN204740293U (en) | 2015-05-08 | 2015-05-08 | Capacitive sensor circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520296701.4U CN204740293U (en) | 2015-05-08 | 2015-05-08 | Capacitive sensor circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204740293U true CN204740293U (en) | 2015-11-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520296701.4U Expired - Fee Related CN204740293U (en) | 2015-05-08 | 2015-05-08 | Capacitive sensor circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN204740293U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107229277A (en) * | 2017-05-31 | 2017-10-03 | 湖南海翼电子商务股份有限公司 | A kind of steep cliff detection circuit and its sweeping robot |
| CN113452325A (en) * | 2021-07-24 | 2021-09-28 | 山东大学 | Envelope detection circuit based on Schmitt circuit and working method thereof |
-
2015
- 2015-05-08 CN CN201520296701.4U patent/CN204740293U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107229277A (en) * | 2017-05-31 | 2017-10-03 | 湖南海翼电子商务股份有限公司 | A kind of steep cliff detection circuit and its sweeping robot |
| CN113452325A (en) * | 2021-07-24 | 2021-09-28 | 山东大学 | Envelope detection circuit based on Schmitt circuit and working method thereof |
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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: 20151104 Termination date: 20180508 |