CN104251938A - Capacitor measurement circuit and system - Google Patents
Capacitor measurement circuit and system Download PDFInfo
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- CN104251938A CN104251938A CN201310261675.7A CN201310261675A CN104251938A CN 104251938 A CN104251938 A CN 104251938A CN 201310261675 A CN201310261675 A CN 201310261675A CN 104251938 A CN104251938 A CN 104251938A
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- resistance
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- capacitance measurement
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- capacitance
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Abstract
The invention discloses a capacitor measurement circuit and system. The system includes the following components: a capacitor measurement unit which is used for measuring a capacitor to be measured so as to output square wave signals, a micro processing unit which is connected with the capacitor measurement unit and is used for receiving the square wave signals and processing the square wave signals so as to output processed signals; and a display unit which is connected with the micro processing unit and is used for displaying the processed signals. With the capacitor measurement circuit and system of the invention adopted, manual calculation is not required, and semi-intellectualization can be realized, and test efficiency is greatly improved compared with the prior art. According to the capacitor measurement circuit and system, after filtering is performed inside the microprocessor, results can be more accurate and have high stability. The capacitor measurement circuit and system are convenient to apply to life and work or commercial promotion.
Description
Technical field
The present invention relates to electronic applications, particularly relate to a kind of circuit and the system of measuring electric capacity.
Background technology
Electric capacity is a kind of with the passive device of electric field form storage power, any two insulated from each other and an electric capacity can be formed between the conductor (comprising wire) of being separated by very near.Electric capacity is one of a large amount of electronic component used in electronic equipment, be widely used in circuit every aspects such as straight-through friendship, coupling, bypass, filtering, resonant tank, energy conversion, controls.
At present, the choosing of size of electric capacity has vital effect to the performance of circuit, even because an electric capacity makes whole circuit cisco unity malfunction, so just seem very important for the measurement of electric capacity in some circuit.
In prior art, test small capacitance, by measuring the change slope of output voltage with test input voltage, calculates testing capacitance value.But its test operation is comparatively difficult, need artificially to calculate, intelligent not, testing efficiency is low, and result is accurate not, and less stable, is not easy to be applied in life or carries out commercialization popularization.Utilize the characteristic of multistage amplification by discharge examination again after capacitor charging in addition, not glittering by judging LED, represent that capacitor internal broken string damages, if the glittering rear luminosity of LED is only dimmed instead of extinguishes, represent that capacitor internal exists electric leakage, if LED Chang Liang does not put out, represent capacitor internal Damage by Short Circuit.But it is for small capacitances, the quality that only can test out electric capacity whether, specifically cannot measure the size of electric capacity.
Summary of the invention
In view of this, the invention provides a kind of method and apparatus of capacitance measurement.
The invention provides a kind of capacitance measurement circuit, it is characterized in that, comprising:
Comparer, the feeder ear of described comparer is connected with power supply, the earth terminal ground connection of described comparer;
First resistance, the first end ground connection of described first resistance, the second end of described first resistance is connected to the in-phase input end of comparer;
Second resistance, the first end of described second resistance is connected to the in-phase input end of described comparer, and the second end of described second resistance is connected with described power supply;
3rd resistance, the first end of described 3rd resistance is connected with the output terminal of described comparer, and the second end of described 3rd resistance is connected to the in-phase input end of described comparer; And
4th resistance, the first end of described 4th resistance is as the first input end of testing capacitance, and the second end of described 4th resistance is connected to the output terminal of described comparer.
More preferably, the first end of described 5th resistance is as the first input end of testing capacitance, and the second end of described 5th resistance is connected to the output terminal of described comparer.
More preferably, the first end of described 6th resistance is as the first input end of testing capacitance, and the second end of described 6th resistance is connected to the output terminal of described comparer.
The invention provides a kind of capacitance measurement system, comprising:
Capacitance measurement unit, for measuring to export square-wave signal to testing capacitance;
Microprocessing unit, is connected with described capacitance measurement unit, for receiving described square-wave signal, and processes described square-wave signal, with the signal after output processing;
Display unit, is connected with described microprocessing unit, for showing the signal after described process.
More preferably, it is characterized in that described capacitance measurement system also comprises:
Extended interface unit, is connected with described microprocessing unit, for directly directly being exported by interface by the signal after described process;
Man-machine interaction unit, is connected with described microprocessing unit, for communicating with described microprocessing unit, selects the signal after by described process to export.
More preferably, described interface comprises serial ports, parallel port, USB, network interface.
More preferably, described capacitance measurement unit comprises:
Comparer, the feeder ear power supply of described comparer connects, the earth terminal ground connection of described comparer;
First resistance, the first end ground connection of described first resistance, the second end of described first resistance is connected to the in-phase input end of comparer;
Second resistance, the first end of described second resistance is connected to the in-phase input end of described comparer, and the second end of described second resistance is connected with described power supply;
3rd resistance, the first end of described 3rd resistance is connected with the output terminal of described comparer, and the second end of described 3rd resistance is connected to the in-phase input end of described comparer; And
4th resistance, the first end of described 4th resistance is as the first input end of testing capacitance, and the second end of described 4th resistance is connected to the output terminal of described comparer.
More preferably, described capacitance measurement unit comprises the 5th resistance, and the first end of described 5th resistance is as the first input end of testing capacitance, and the second end of described 5th resistance is connected to the output terminal of described comparer.
More preferably, described capacitance measurement unit comprises the 6th resistance, and the first end of described 6th resistance is as the first input end of testing capacitance, and the second end of described 6th resistance is connected to the output terminal of described comparer.
The present invention, without the need to artificial calculating, achieves Semi-intelligent Modular, and testing efficiency has greatly improved compared with scheme in the past, carries out filtering make result more accurate through microprocessor internal, and stability is better, is convenient to be applied in life and work or carries out commercialization popularization.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the capacitance measurement circuit figure of the embodiment of the present invention;
Fig. 2 be the embodiment of the present invention to graph of relation during capacitor charging;
Fig. 3 be the embodiment of the present invention to graph of relation during capacitor discharge;
Fig. 4 is the capacitance measurement circuit figure of another embodiment of the present invention;
Fig. 5 is the capacitance measurement system schematic diagram of the embodiment of the present invention.
Embodiment
In order to make technical matters to be solved by this invention, technical scheme and beneficial effect clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.
Please refer to Fig. 1, Fig. 1 is the capacitance measurement circuit figure of the embodiment of the present invention.As shown in the figure, the first end ground connection of resistance R1, second end of resistance R1 is connected to the in-phase input end of comparer.The first end of resistance R2 is connected to the in-phase input end of comparer, and second end of resistance R2 is connected with power Vcc.The first end of resistance R3 is connected with the output terminal of comparer, and second end of resistance R3 is connected to the in-phase input end of comparer.The first end of resistance R is as the first input end of testing capacitance, and second end of resistance R is connected to the output terminal of comparer.Second input end grounding of testing capacitance.
According to physical circuit connected mode as shown in Figure 1, the supply voltage Vcc=V of comparer, the resistor network that R1, R2, R3 that outer three resistances of sheet are equal are formed provides the reference voltage of comparer in-phase input end U+, this reference voltage is subject to the feedback excitation of the output of comparer, the periodic transformation between 1/3VCC and 2/3VCC of its magnitude of voltage.When powering on, the output voltage of circuit
, R2 and R3 parallel equivalent resistance is 0.5R1, is divided to the voltage of comparer in-phase input end with resistance R1
.
Please refer to Fig. 2, Fig. 2 be the embodiment of the present invention to graph of relation during capacitor charging.Uo is charged to electric capacity C by R, the current potential U-t exponentially curve growth in time of comparer inverting input
, as figure (in figure V=3V, RC=0.03s).Voltage comparator can be regarded as the operational amplifier of enlargement factor close to " infinity ", so voltage comparator is for comparing the size of two voltages (with the high or low level of output voltage, represent the magnitude relationship of two input voltages): when "+" input terminal voltage is higher than "-" input end, voltage comparator exports as high level; When "+" input terminal voltage is lower than "-" input end, voltage comparator exports as low level; So work as U-once reach
critical after, U-slightly increases again, and output voltage Uo is just 0 from V transition, and now R1 and R3 parallel equivalent resistance is 0.5R1, and the voltage that R2 is divided to comparer U+ is:
.
Please refer to Fig. 3, Fig. 3 be the embodiment of the present invention to graph of relation during capacitor discharge.Electric capacity C is discharged by R, the voltage U-t exponentially curve reduction in time of inverting input
, U-is tending towards because of electric discharge
; But once when U-slightly reduces (U-< U+) again, Uo is just V from 0 transition, meanwhile electric capacity starts again homophase and charges.Said process goes round and begins again, and circuit creates self-oscillation and exports periodic signal of square wave, this signal high level time be electric capacity by
arrive
duration of charging, low level time is electric capacity
arrive
discharge time, so can this square wave signal period be:
Frequency is:
As can be seen here, when resistance R mono-timing, this square wave signal frequency f becomes inverse relation completely with electric capacity C, so by the regular periodic signal of square wave of this tool of microprocessor repeated detection, again by just being shown by display unit after microprocessor internal process, obtain the size of testing capacitance.
Please refer to Fig. 4, Fig. 4 is the capacitance measurement circuit figure of another embodiment of the present invention.As shown in the figure, the first end ground connection of resistance R1, second end of resistance R1 is connected to the in-phase input end of comparer.The first end of resistance R2 is connected to the in-phase input end of comparer, and second end of resistance R2 is connected with power Vcc.The first end of resistance R3 is connected with the output terminal of comparer, and second end of resistance R3 is connected to the in-phase input end of comparer.The first end of resistance RA is as the first input end of testing capacitance, and second end of resistance RA is connected to the output terminal of comparer.The first end of resistance RB is as the first input end of testing capacitance, and second end of resistance RB is connected to the output terminal of comparer.The first end of resistance RC is as the first input end of testing capacitance, and second end of resistance RC is connected to the output terminal of comparer.Second input end grounding of testing capacitance.Due to the different order of magnitude having pico farad (pf) level, nanofarad (nf) level, microfarad (uf) level etc. to differ greatly when surveying electric capacity, therefore the circuit of the present embodiment is compared with the circuit in Fig. 1, add the switch of more detailed classification, to make measurement more accurate.
Please refer to Fig. 5, Fig. 5 is the capacitance measurement system schematic diagram of the embodiment of the present invention.Capacitance measurement system comprises capacitance measurement unit 501, microprocessing unit 502, display unit 503.
Capacitance measurement unit 501, for measuring to export square-wave signal to testing capacitance;
Microprocessing unit 502, is connected with capacitance measurement unit, for receiving square-wave signal, and processes square-wave signal, with the signal after output processing;
Display unit 503, is connected with microprocessing unit 502, for the signal after Graphics Processing.
In this embodiment, also extended interface unit 504 and man-machine interaction unit 505 can be comprised further.Extended interface unit 504 is connected with microprocessing unit 502, for directly directly being exported by interfaces such as serial ports, parallel port, USB, network interfaces by the signal after output processing.Man-machine interaction unit 505 is connected with microprocessing unit 502, for communicating with microprocessing unit, selects the signal after by process to export with different interfaces.
The brand-new thoughts and methods that the present invention opens for capacitance measurement, is in particular in:
1. comparer of arranging in pairs or groups on the basis of capacitor charge and discharge principle proposes a kind of new capacitance measurement circuit;
2. propose a whole set of implementation automatically to measure electric capacity, intelligence degree is higher;
3. test operation is succinct, without the need to artificial calculating, achieves Semi-intelligent Modular, testing efficiency has greatly improved compared with scheme in the past, carrying out filtering through microprocessor internal makes result more accurate, and stability is better, is convenient to be applied in life and work or carries out commercialization popularization.
It should be noted that, through the above description of the embodiments, those skilled in the art can be well understood to the mode that the present invention can add required hardware platform by software and realize, and can certainly all be implemented by hardware.Based on such understanding, what technical scheme of the present invention contributed to background technology can embody with the form of software product in whole or in part, this computer software product can be stored in storage medium, as ROM/RAM, magnetic disc, CD etc., comprising some instructions in order to make a computer equipment (can be personal computer, server, or the network equipment etc.) perform the method described in some part of each embodiment of the present invention or embodiment.
The above disclosed preferred embodiment be only in the embodiment of the present invention, certainly can not limit the interest field of the present invention, therefore according to the equivalent variations that the claims in the present invention are done, still belong to the scope that the present invention is contained with this.
Claims (9)
1. a capacitance measurement circuit, is characterized in that, comprising:
Comparer, the feeder ear of described comparer is connected with power supply, the earth terminal ground connection of described comparer;
First resistance, the first end ground connection of described first resistance, the second end of described first resistance is connected to the in-phase input end of comparer;
Second resistance, the first end of described second resistance is connected to the in-phase input end of described comparer, and the second end of described second resistance is connected with described power supply;
3rd resistance, the first end of described 3rd resistance is connected with the output terminal of described comparer, and the second end of described 3rd resistance is connected to the in-phase input end of described comparer; And
4th resistance, the first end of described 4th resistance is as the first input end of testing capacitance, and the second end of described 4th resistance is connected to the output terminal of described comparer.
2. capacitance measurement circuit as claimed in claim 1, is characterized in that, the first end of described 5th resistance is as the first input end of testing capacitance, and the second end of described 5th resistance is connected to the output terminal of described comparer.
3. capacitance measurement circuit as claimed in claim 2, is characterized in that, the first end of described 6th resistance is as the first input end of testing capacitance, and the second end of described 6th resistance is connected to the output terminal of described comparer.
4. a capacitance measurement system, comprising:
Capacitance measurement unit, for measuring to export square-wave signal to testing capacitance;
Microprocessing unit, is connected with described capacitance measurement unit, for receiving described square-wave signal, and processes described square-wave signal, with the signal after output processing;
Display unit, is connected with described microprocessing unit, for showing the signal after described process.
5. capacitance measurement system as claimed in claim 4, is characterized in that described capacitance measurement system also comprises:
Extended interface unit, is connected with described microprocessing unit, for directly directly being exported by interface by the signal after described process;
Man-machine interaction unit, is connected with described microprocessing unit, for communicating with described microprocessing unit, selects the signal after by described process to export.
6. capacitance measurement system as claimed in claim 5, it is characterized in that, described interface comprises serial ports, parallel port, USB, network interface.
7. capacitance measurement system as claimed in claim 4, is characterized in that described capacitance measurement unit comprises:
Comparer, the feeder ear of described comparer is connected with power supply, the earth terminal ground connection of described comparer;
First resistance, the first end ground connection of described first resistance, the second end of described first resistance is connected to the in-phase input end of comparer;
Second resistance, the first end of described second resistance is connected to the in-phase input end of described comparer, and the second end of described second resistance is connected with described power supply;
3rd resistance, the first end of described 3rd resistance is connected with the output terminal of described comparer, and the second end of described 3rd resistance is connected to the in-phase input end of described comparer; And
4th resistance, the first end of described 4th resistance is as the first input end of testing capacitance, and the second end of described 4th resistance is connected to the output terminal of described comparer.
8. capacitance measurement system as claimed in claim 7, it is characterized in that described capacitance measurement unit comprises the 5th resistance, the first end of described 5th resistance is as the first input end of testing capacitance, and the second end of described 5th resistance is connected to the output terminal of described comparer.
9. capacitance measurement system as claimed in claim 8, it is characterized in that described capacitance measurement unit comprises the 6th resistance, the first end of described 6th resistance is as the first input end of testing capacitance, and the second end of described 6th resistance is connected to the output terminal of described comparer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310261675.7A CN104251938A (en) | 2013-06-27 | 2013-06-27 | Capacitor measurement circuit and system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310261675.7A CN104251938A (en) | 2013-06-27 | 2013-06-27 | Capacitor measurement circuit and system |
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| CN104251938A true CN104251938A (en) | 2014-12-31 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116559545A (en) * | 2023-07-10 | 2023-08-08 | 宏晶微电子科技股份有限公司 | Capacitor frequency conversion circuit and integrated circuit chip |
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| US4175239A (en) * | 1978-04-12 | 1979-11-20 | P. R. Mallory & Co. Inc. | Detection means for touch control switches |
| CN1766660A (en) * | 2004-09-08 | 2006-05-03 | 欧姆龙株式会社 | Capacitance measuring arrangement, method, and program |
| CN101499794A (en) * | 2008-01-31 | 2009-08-05 | 杭州利尔达科技有限公司 | Capacitor induction type touch press-key and measuring method for touch press-key capacitor |
| CN102385009A (en) * | 2010-09-01 | 2012-03-21 | 錞镱科技股份有限公司 | Measuring device for capacitance and method thereof |
| CN103176053A (en) * | 2011-12-23 | 2013-06-26 | 鸿富锦精密工业（深圳）有限公司 | Measuring circuit for capacity and parasitic resistance of capacitor |
-
2013
- 2013-06-27 CN CN201310261675.7A patent/CN104251938A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4175239A (en) * | 1978-04-12 | 1979-11-20 | P. R. Mallory & Co. Inc. | Detection means for touch control switches |
| CN1766660A (en) * | 2004-09-08 | 2006-05-03 | 欧姆龙株式会社 | Capacitance measuring arrangement, method, and program |
| CN101499794A (en) * | 2008-01-31 | 2009-08-05 | 杭州利尔达科技有限公司 | Capacitor induction type touch press-key and measuring method for touch press-key capacitor |
| CN102385009A (en) * | 2010-09-01 | 2012-03-21 | 錞镱科技股份有限公司 | Measuring device for capacitance and method thereof |
| CN103176053A (en) * | 2011-12-23 | 2013-06-26 | 鸿富锦精密工业（深圳）有限公司 | Measuring circuit for capacity and parasitic resistance of capacitor |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116559545A (en) * | 2023-07-10 | 2023-08-08 | 宏晶微电子科技股份有限公司 | Capacitor frequency conversion circuit and integrated circuit chip |
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Application publication date: 20141231 |