CN103439581B - A kind of metering circuit - Google Patents
A kind of metering circuit Download PDFInfo
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- CN103439581B CN103439581B CN201310384808.XA CN201310384808A CN103439581B CN 103439581 B CN103439581 B CN 103439581B CN 201310384808 A CN201310384808 A CN 201310384808A CN 103439581 B CN103439581 B CN 103439581B
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- electric capacity
- effect transistor
- field effect
- output terminal
- divider
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Abstract
The present invention discloses a kind of metering circuit, comprise: signal source, voltage-divider, measuring circuit and millivoltmeter, the input terminus of voltage-divider is connected with the output terminal of signal source, and the output terminal of this voltage-divider is connected with the input terminus of measuring circuit, and the output terminal of described measuring circuit is connected with millivoltmeter; Material required for the present invention can be looked for everywhere, and makes simple, and cost is low, is applicable to impedance measurement accurately little, but needs the crowd comparing impedance magnitude to use, particularly User, stable performance of the present invention.
Description
Technical field
The present invention relates to a kind of metering circuit, in particular to the circuit for impedance measurement.
Background technology
At present, the multiple range impedance measuring Instrument of multi-usage, can in order to measure the natural impedance etc. of the Q value in high-frequency inductor or resonance loop, the inductance amount of inducer and distributed capacity amount, the electrical capacity of electrical condenser and loss angle, the high-frequency dielectric loss of electrical material, effective parallel connection in high frequency loop and series resistance, transmission line. Although but current impedance measuring Instrument Q table precision height, but it is expensive, and applicable crowd is narrower, and popularity rate is low, and particularly for students, when testing, required surveying instrument accuracy requirement is not high, but should expensive and unable undertake.
Therefore need a kind of new technical scheme to solve the problem.
Summary of the invention
Goal of the invention: for above-mentioned prior art Problems existing and deficiency, it is an object of the invention to provide a kind of metering circuit, and its cost is low, stable performance.
Technical scheme: the technical solution used in the present invention is a kind of metering circuit, comprise signal source, measuring circuit and voltage-divider, the input terminus of voltage-divider is connected with the output terminal of signal source, and the output terminal of this voltage-divider is connected with the input terminus of measuring circuit, and the output terminal of measuring circuit is connected with millivoltmeter; 5th electric capacity of voltage-divider (all in parallel to the 14 electric capacity, then the one end with the 4th electric capacity is connected; Described signal source is made up of LC oscillator circuit, first inductance and the 2nd Capacitance parallel connection, its side is ground connection simultaneously, another side is connected with the grid of field effect transistor, the source electrode of field effect transistor is connected with the input terminus of two-stage common base amplifier, and the output terminal of two-stage common base amplifier is connected with the grid of field effect transistor.
Integrally, and side simultaneously ground connection, is easy to starting of oscillation, and oscillation amplitude is stablized, and device parameter values is insensitive, and oscillation wave is good, vibration regulation range width, regulates the amplitude-frequency characteristic of oscillating capacitance steady in LC shunt-resonant circuit.
Preferably, two-stage common base amplifier is made up of triode, and the emtting electrode of the first triode is connected with the source electrode of field effect transistor, and its collector electrode is connected with the emtting electrode of the 2nd triode, and the collector electrode of the 2nd triode is connected with the grid of field effect transistor. .
Preferably, the source electrode of field effect transistor is the output terminal of signal source, and the other end of the 4th electric capacity is connected with the source electrode of field effect transistor.
Preferably, the 5th electric capacity is identical to the capacitance of the 14 electric capacity, and the capacitance of the 4th electric capacity is 1/10th of the 5th electric capacity.
Useful effect: compared with prior art, the material that its advantage is required for the present invention can be looked for everywhere in the present invention, and make simple, cost is low, is applicable to impedance measurement accurately little, but needs the crowd comparing impedance magnitude to use, particularly User, stable performance of the present invention.
Accompanying drawing explanation
Fig. 1 is the structural representation of the present invention;
Fig. 2 is the signal source circuit figure of invention;
Fig. 3 is the overall schematic circuit of the present invention.
Embodiment
As shown in Figure 1, this circuit of the present invention comprises signal source, measuring circuit and voltage-divider, the input terminus of described voltage-divider is connected with the output terminal of signal source, and the output terminal of this voltage-divider is connected with the input terminus of measuring circuit, and the output terminal of described measuring circuit is connected with millivoltmeter;
As shown in Figure 2, signal source is made up of LC oscillator circuit, first inductance L 1 and the 2nd electric capacity C2 are in parallel, its side is ground connection simultaneously, another side is connected with the grid of field effect transistor Q1, the source electrode of field effect transistor Q1 is connected with the input terminus of two-stage common base amplifier, and the output terminal of two-stage common base amplifier is connected with the grid of field effect transistor Q1; Two-stage common base amplifier is made up of triode, and the emtting electrode of the first triode Q3 is connected with the source electrode of field effect transistor Q1, and its collector electrode is connected with the emtting electrode of the 2nd triode Q2, and the collector electrode of the 2nd triode Q2 is connected with the grid of field effect transistor Q1
As shown in Figure 3, the 5th electric capacity C5 of voltage-divider is all in parallel to the 14 electric capacity C14, then the one end with the 4th electric capacity C4 is connected; The source electrode of field effect transistor Q1 is the output terminal of signal source, and the other end of the 4th electric capacity C4 is connected with the source electrode of field effect transistor Q1; 5th electric capacity C5 is identical to the capacitance of the 14 electric capacity C14, and the capacitance of the 4th electric capacity C4 is 1/10th of the 5th electric capacity C5.
The other end of the 5th electric capacity C5 accesses tested inductance LXOne end, tested inductance LXThe other end be connected with one end of variable capacity, the other end ground connection of variable capacity, measured capacitance CXIn parallel with variable capacity.
Fixed signal source exports with the positive string signal of frequency with amplitude, and millivoltmeter can be converted by voltmeter, i.e. impedance value is output voltage and input voltage ratio.
Material required for the present invention can be looked for everywhere, and makes simple, and cost is low, is applicable to impedance measurement accurately little, but needs the crowd comparing impedance magnitude to use, particularly User, stable performance of the present invention.
Claims (2)
1. a metering circuit, it is characterized in that: this circuit comprises signal source, measuring circuit and voltage-divider, the input terminus of described voltage-divider is connected with the output terminal of signal source, and the output terminal of this voltage-divider is connected with the input terminus of measuring circuit, and the output terminal of described measuring circuit is connected with millivoltmeter, 5th electric capacity (C5) of described voltage-divider is all in parallel to the 14 electric capacity (C14), then the one end with the 4th electric capacity (C4) is connected, the other end of the 5th electric capacity (C5) accesses one end of tested inductance, the other end of tested inductance is connected with one end of variable capacity, the other end ground connection of variable capacity, measured capacitance is in parallel with variable capacity, described signal source is made up of LC oscillator circuit, first inductance (L1) and the 2nd electric capacity (C2) are in parallel, its side is ground connection simultaneously, another side is connected with the grid of field effect transistor (Q1), the source electrode of field effect transistor (Q1) is connected with the input terminus of two-stage common base amplifier, the output terminal of two-stage common base amplifier is connected with the grid of field effect transistor (Q1), described two-stage common base amplifier is made up of triode, the emtting electrode of the first triode (Q3) is connected with the source electrode of field effect transistor (Q1), its collector electrode is connected with the emtting electrode of the 2nd triode (Q2), the collector electrode of the 2nd triode (Q2) is connected with the grid of field effect transistor (Q1), the source electrode of field effect transistor (Q1) is the output terminal of signal source, the other end of the 4th electric capacity (C4) is connected with the source electrode of field effect transistor (Q1).
2. a kind of metering circuit according to claim 1, it is characterized in that: the 5th electric capacity (C5) is identical to the capacitance of the 14 electric capacity (C14), the capacitance of the 4th electric capacity (C4) is 1/10th of the 5th electric capacity (C5).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310384808.XA CN103439581B (en) | 2013-08-30 | 2013-08-30 | A kind of metering circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310384808.XA CN103439581B (en) | 2013-08-30 | 2013-08-30 | A kind of metering circuit |
Publications (2)
| Publication Number | Publication Date |
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| CN103439581A CN103439581A (en) | 2013-12-11 |
| CN103439581B true CN103439581B (en) | 2016-06-01 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201310384808.XA Active CN103439581B (en) | 2013-08-30 | 2013-08-30 | A kind of metering circuit |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3648165A (en) * | 1970-09-24 | 1972-03-07 | Sun Oil Co | Capacitance-measuring apparatus including means maintaining the voltage across the unknown capacitance constant |
| CN86102187A (en) * | 1986-04-01 | 1987-10-21 | 湖北省计量测试研究所 | High frequency inducdtance and capacitance measuring instrument |
| CN102253286A (en) * | 2011-06-27 | 2011-11-23 | 郑军 | Resistance/capacitance measuring method and device thereof |
| CN102636701A (en) * | 2012-04-17 | 2012-08-15 | 深南电路有限公司 | Inductor detecting instrument and method |
-
2013
- 2013-08-30 CN CN201310384808.XA patent/CN103439581B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3648165A (en) * | 1970-09-24 | 1972-03-07 | Sun Oil Co | Capacitance-measuring apparatus including means maintaining the voltage across the unknown capacitance constant |
| CN86102187A (en) * | 1986-04-01 | 1987-10-21 | 湖北省计量测试研究所 | High frequency inducdtance and capacitance measuring instrument |
| CN102253286A (en) * | 2011-06-27 | 2011-11-23 | 郑军 | Resistance/capacitance measuring method and device thereof |
| CN102636701A (en) * | 2012-04-17 | 2012-08-15 | 深南电路有限公司 | Inductor detecting instrument and method |
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| CN103439581A (en) | 2013-12-11 |
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