CN102478609A - Capacitor measuring method and capacitor test circuit - Google Patents
Capacitor measuring method and capacitor test circuit Download PDFInfo
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- CN102478609A CN102478609A CN2010105909671A CN201010590967A CN102478609A CN 102478609 A CN102478609 A CN 102478609A CN 2010105909671 A CN2010105909671 A CN 2010105909671A CN 201010590967 A CN201010590967 A CN 201010590967A CN 102478609 A CN102478609 A CN 102478609A
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Abstract
The invention relates to a capacitor measuring method and a capacitor test circuit which are used for measuring a capacitance of a capacitor. The capacitor measuring method comprises the following steps: inputting power to a capacitor; when the voltage of the capacitor reaches a first preset voltage, stopping inputting the power to the capacitor; electrically connecting the capacitor to a discharge resistor, and recording a discharge start time point; when the voltage of the capacitor drops to a second preset voltage, recording a discharge stop time point; and calculating the capacitance of the capacitor according to the discharge start time point, the discharge stop time point and the resistance of the discharge resistor. When being used for measuring the capacitance of the capacitor, the capacitor measuring method and the test circuit not only can effectively lower the complexity of the existing detection method, but also can achieve the goals of reducing errors and facilitating implementation.
Description
Technical field
The present invention relates to a kind of capacitor measuring method and capacitor testing circuit, relate in particular to a kind of measuring method and its test circuit in order to the capacitance that detects capacitor.
Background technology
Generally speaking, electric capacity actual voltage that bears in different circuit can not surpass its withstand voltage.Therefore, different circuits should be selected different types of electric capacity for use.For example, circuit loop such as resonance, transformation can be selected high frequency capacitances such as mica, pottery for use; And filtering circuit can be selected the electrolysis shunt capacitance for use.Before all kinds of electric capacity dispatch from the factory and electrically are arranged at side circuit, all must accomplish its electrical detection, just measure the whether correct check operation of its capacitance.
For example, when whether the capacitance that detects electric capacity is correct, mainly be fixing voltage source to be provided, with the charging testing capacitance through a test circuit.Then, after testing capacitance is accomplished charging, the action of again testing capacitance being discharged.Conventional detection is through the discharge curve of acquisition testing capacitance, and the linear segments that is directed against in this discharge curve is carried out data sampling, the continuous capacitance that obtains testing capacitance with the estimation of differential formula.
Yet mostly general capacitance discharges curve is the polynomial parabolic curve that binomial or binomial are above.With regard to actual horizon, conventional detection, necessary extra assistant is with the computing formula of approximately linear, to obtain the linear segments that is suitable in its curve as data sampling.Under this situation, conventional detection has not only increased the complexity in the computation process (complexity), has more intangibly brought the error of calculation in the computation process, therefore, is more difficult to get accurate data.
Secondly, in order to obtain accurate capacitance, conventional detection is also relatively high for the accuracy requirement of discharge curve.Under this situation, in order to the voltage source of charging power to be provided, the stability of its output power (reliability) important that promptly seems.In other words; Charge voltage source must provide stable power source; And has stable output characteristics; With the probability of effectively avoiding surging in the discharge curve (spikes), harmonic wave (harmonics) and noise (noises) etc. to take place, in this, conventional detection is in the rising that also causes testing cost virtually.
In sum, how to solve the problem that existing detection method is produced, and a kind of the have easy method of measuring capacitance of low error, pin-point accuracy and operation, the real problem that presses for solution for the correlative technology field person at present are provided.
Summary of the invention
Seeing that more than, the object of the present invention is to provide a kind of measuring method and test circuit that is suitable for the capacitance of Measurement of capacitor, to solve the existing problem that exists.
To achieve these goals, the present invention provides a kind of capacitor measuring method, is suitable for measuring the capacitance of a capacitor.This kind capacitor measuring method may further comprise the steps: import a power supply in this capacitor; When the magnitude of voltage of this capacitor reaches one first scheduled voltage, stop to import power supply in this capacitor; Electrically connect this capacitor to one discharge resistance, and write down a discharge starting time point; When the magnitude of voltage of this capacitor drops to one second scheduled voltage, record 1 discharge point closing time; And, calculate the capacitance of this capacitor according to the resistance value of discharge starting time point, discharge point closing time and discharge resistance.
Capacitor measuring method according to an embodiment of the invention, when wherein first scheduled voltage was E0, second scheduled voltage can be 0.37E0.
Capacitor measuring method according to an embodiment of the invention, wherein the resistance value of discharge resistance is R, discharge starting time point with put the closing time of discharging between the formation time interval of delta t, the capacitance of this capacitor is to be Δ t/R.
To achieve these goals, the present invention also provides a kind of capacitor testing circuit, is suitable for measuring the capacitance of a capacitor.This kind capacitor testing circuit comprises: a power supply module, a discharge resistance, a switch element and a detection record module.Wherein, power supply module is in order to provide a power supply, and switch element optionally electrically connects this capacitor to discharge resistance or power supply module, and the detection record module is in order to write down a magnitude of voltage of this capacitor.When this magnitude of voltage reached one first scheduled voltage, detection record module controls switch element electrically connected this capacitor to discharge resistance, and write down a discharge starting time point.When this magnitude of voltage drops to one second scheduled voltage, detection record module records 1 discharge point closing time.The capacitance of this capacitor calculates according to the resistance value of discharge starting time point, discharge point closing time and discharge resistance in detection record module system.
So capacitor measuring method and capacitor testing circuit that the present invention proposes are through power supply module the power supply that charges in testing capacitor to be provided earlier.Thereafter, the ratio that detection record module records testing capacitor voltage in discharge process descends, with and corresponding institute elapsed time.According to the resistance value of those data and discharge resistance, the detection record module can calculate the capacitance of testing capacitor.
Capacitor measuring method and capacitor testing circuit that the present invention proposes have not only been save the restriction of existing detection method to the charge power supply accuracy requirement, and it is higher also to reach accuracy rate simultaneously, and the effect of being convenient to implement.
Describe the present invention below in conjunction with accompanying drawing and specific embodiment, but not as to qualification of the present invention.
Description of drawings
Fig. 1 is the flow chart of steps according to the capacitor measuring method of the embodiment of the invention;
Fig. 2 is the circuit block diagram according to the test circuit of the embodiment of the invention;
The circuit block diagram of Fig. 3 A for charging according to the test circuit of Fig. 2 when the capacitor;
The circuit block diagram of Fig. 3 B for discharging according to the test circuit of Fig. 2 when the capacitor.
Wherein, Reference numeral
10 power supply modules
12 discharge resistances
14 switch elements
16 detection record modules
18 capacitors
100 test circuits
Embodiment
Below in embodiment, be described in detail detailed features of the present invention and advantage; Its content is enough to make any those skilled in the art to understand technology contents of the present invention and implements according to this; And according to content, claim scope and the accompanying drawing that this instructions disclosed, any those skilled in the art can understand purpose and the advantage that the present invention is correlated with easily.
Fig. 1 is the flow chart of steps according to the capacitor measuring method of the embodiment of the invention, and this kind measuring method is applicable to the test circuit of Fig. 2, to measure the capacitance of capacitor in this test circuit.Wherein, it should be noted that the measuring method that the present invention proposes, do not exceed with the capacitor of measuring in the test circuit shown in Figure 2.Below about the two cooperation explanation, only as the usefulness of explaining technology contents demonstration of the present invention.Any those skilled in the art are when being applied to measure the capacitance of testing capacitor in other test circuit according to summary of the invention of the present invention, with purpose and the advantage that realizes that the present invention is correlated with voluntarily.
According to embodiments of the invention; As shown in Figure 2; Test circuit 100 comprises power supply module 10, discharge resistance 12, switch element 14 and detection record module 16; Wherein power supply module 10 is in order to provide a power supply Vin, and switch element 14 is connected between power supply module 10, discharge resistance 12 and the capacitor 18.Switch element 14 also optionally switches between contact A and the contact B, to electrically connect capacitor 18 to power supply module 10 or discharge resistance 12.Detection record module 16 is parallel to capacitor 18, with the magnitude of voltage Uc of record capacitor 18.According to embodiments of the invention, test circuit 100 can be in order to the capacitance of Measurement of capacitor 18, its measuring method, and the flow chart of steps of please consulting Fig. 1 in the lump, explanation now is as follows.
At first, shown in Fig. 3 A, switch element 14 connects contact A, to electrically connect capacitor 18 to power supply module 10, makes power supply Vin charge in capacitor 18 (corresponding step S100).Then, detection record module 16 judges whether the magnitude of voltage Uc of capacitor 18 reaches one first scheduled voltage E0 (corresponding step S102), and wherein the first scheduled voltage E0 can be but be not limited to 1.2 volts (V).When the magnitude of voltage Uc of capacitor 18 reaches the first scheduled voltage E0; Power supply module 10 stops to import power supply Vin in capacitor 18; And shown in Fig. 3 B, switch element 14 transfers to connect contact B, so that capacitor 18 is electrically connected to discharge resistance 12; In this, detection record module 16 records one discharge starting time point T0 (corresponding step S104 and S106).
Following in this situation, discharge resistance 12 forms a discharge loop with capacitor 18.Then according to following formula:
U
c+iR＝0；
Wherein R is the resistance value of discharge resistance 12, and i is the electric current of discharge resistance 12 of flowing through; And
When Δ t=0 (promptly corresponding discharge starting time point T0), the magnitude of voltage Uc of capacitor 18 is the first scheduled voltage E0, can solve thus:
When Δ t=RC, U
c=E
0* e
-1=0.37E
0
Therefore, shown in step S108, detection record module 16 judges whether the magnitude of voltage Uc of capacitor 18 drops to one second scheduled voltage, and wherein second scheduled voltage can be set at 0.37E0.In this, when the magnitude of voltage Uc of capacitor 18 dropped to 0.37E0, detection record module 16 promptly write down a discharge and puts T1 (corresponding step S110) closing time.So according to Δ t=RC, Δ t puts the time interval between T1 and the discharge starting time point T0 for discharge closing time, detection record module 16 can calculate the capacitance C=Δ t/R (corresponding step S112) of capacitor 18.
Secondly, the capacitor testing method that proposes according to the present invention, the ratio of second scheduled voltage and the first scheduled voltage E0 can be but be not limited to 0.37 times.In detail; Wherein Δ t also can be selected from 0.5RC or 2RC according to
, makes Uc=0.608E0 or 0.1369E0.Through setting second scheduled voltage is 0.608 times or 0.1369 times of the first scheduled voltage E0; Record discharges and puts the time interval Δ t between T1 and the discharge starting time point T0 closing time; According to Δ t=0.5RC or 2RC, can calculate the capacitance C of capacitor 18 again.
In sum; The capacitor measuring method that the present invention proposes; Capacitor testing circuit with its application; The magnitude of voltage that only needs to detect testing capacitor from first scheduled voltage drop to second scheduled voltage between institute's elapsed time, and the resistance value of discharge resistance can calculate the capacitance of testing capacitor.
The capacitor measuring method and the capacitor testing circuit that utilize the present invention to propose; When detecting the capacitance of capacitor; Not only can effectively save existing complicated calculation procedure; More need not to write down the concrete magnitude of voltage of capacitor each in discharge process, a low error, accuracy height and operation intuition capacitance test method simply and easily is provided by this.
Certainly; The present invention also can have other various embodiments; Under the situation that does not deviate from spirit of the present invention and essence thereof; Those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection domain of the appended claim of the present invention.
Claims (6)
1. capacitor measuring method is suitable for measuring the capacitance of a capacitor, it is characterized in that this capacitor measuring method comprises:
Import a power supply in this capacitor;
When the magnitude of voltage of this capacitor reaches one first scheduled voltage, stop to import this power supply in this capacitor;
Electrically connect this capacitor to one discharge resistance, and write down a discharge starting time point;
When the magnitude of voltage of this capacitor drops to one second scheduled voltage, record 1 discharge point closing time; And
According to the resistance value of this discharge starting time point, this discharge point closing time and this discharge resistance, calculate the capacitance of this capacitor.
2. capacitor measuring method according to claim 1 is characterized in that, when this first scheduled voltage was E0, this second scheduled voltage was 0.37E0.
3. capacitor measuring method according to claim 2 is characterized in that, the resistance value of this discharge resistance is R, formation time interval of delta t between this discharge starting time point and this discharge point closing time, and the capacitance of this capacitor is Δ t/R.
4. capacitor testing circuit is suitable for measuring the capacitance of a capacitor, it is characterized in that this capacitor testing circuit comprises:
One power supply module is in order to provide a power supply;
One discharge resistance;
One switch element optionally electrically connects this capacitor to this discharge resistance or this power supply module; And
One detection record module writes down a magnitude of voltage of this capacitor;
Wherein, When this magnitude of voltage reached one first scheduled voltage, this switch element of this detection record module controls electrically connected this capacitor to this discharge resistance, and write down a discharge starting time point; When this magnitude of voltage drops to one second scheduled voltage; This detection record module records 1 discharge point closing time, this detection record module calculate the capacitance of this capacitor according to the resistance value of this discharge starting time point, this discharge point closing time and this discharge resistance.
5. capacitor testing circuit according to claim 4 is characterized in that, when this first scheduled voltage was E0, this second scheduled voltage was 0.37E0.
6. capacitor testing circuit according to claim 5 is characterized in that, the resistance value of this discharge resistance is R, formation time interval of delta t between this discharge starting time point and this discharge point closing time, and the capacitance of this capacitor is Δ t/R.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010105909671A CN102478609A (en) | 2010-11-30 | 2010-11-30 | Capacitor measuring method and capacitor test circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010105909671A CN102478609A (en) | 2010-11-30 | 2010-11-30 | Capacitor measuring method and capacitor test circuit |
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| CN102478609A true CN102478609A (en) | 2012-05-30 |
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| CN2010105909671A Pending CN102478609A (en) | 2010-11-30 | 2010-11-30 | Capacitor measuring method and capacitor test circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103308777A (en) * | 2013-05-29 | 2013-09-18 | 漳州师范学院 | Measurement method of capacitor and inductor |
| CN105425050A (en) * | 2015-12-17 | 2016-03-23 | 河源广工大协同创新研究院 | Farad meter for ultrahigh capacitance detection |
| CN112485640A (en) * | 2020-11-18 | 2021-03-12 | 苏州华兴源创科技股份有限公司 | Detection method and device for built-in capacitor, detection equipment and storage medium |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5329239A (en) * | 1991-05-24 | 1994-07-12 | Abb Patent Gmbh | Circuit for measuring a capacitance during constant charging and discharging periods |
-
2010
- 2010-11-30 CN CN2010105909671A patent/CN102478609A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5329239A (en) * | 1991-05-24 | 1994-07-12 | Abb Patent Gmbh | Circuit for measuring a capacitance during constant charging and discharging periods |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103308777A (en) * | 2013-05-29 | 2013-09-18 | 漳州师范学院 | Measurement method of capacitor and inductor |
| CN103308777B (en) * | 2013-05-29 | 2016-02-03 | 漳州师范学院 | The measuring method of electric capacity and inductance |
| CN105425050A (en) * | 2015-12-17 | 2016-03-23 | 河源广工大协同创新研究院 | Farad meter for ultrahigh capacitance detection |
| CN112485640A (en) * | 2020-11-18 | 2021-03-12 | 苏州华兴源创科技股份有限公司 | Detection method and device for built-in capacitor, detection equipment and storage medium |
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Application publication date: 20120530 |