CN202330600U - LCR (inductor-capacitor-resistor) tester - Google Patents
LCR (inductor-capacitor-resistor) tester Download PDFInfo
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- CN202330600U CN202330600U CN2011204943069U CN201120494306U CN202330600U CN 202330600 U CN202330600 U CN 202330600U CN 2011204943069 U CN2011204943069 U CN 2011204943069U CN 201120494306 U CN201120494306 U CN 201120494306U CN 202330600 U CN202330600 U CN 202330600U
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Abstract
An LCR (inductor-capacitor-resistor) tester comprises a reference clock, three DDS (Direct Digital Synthesis) signal sources, a measurement signal generator, a source resistor, an input circuit, an automatic balanced bridge, two filters, two mixers, two A/D (analog-to-digital) converters and an ARM processor, the three DDS signal sources are connected with the reference clock, the input circuit is connected with a tested element, testing signals drive the tested element via the source resistor, the tested element is connected with a set of four-terminal-pair structure through the input circuit, the automatic balanced bridge ensures that the Lp terminal is always virtually grounded, and two routes of vector voltages are generated. After being respectively filtered and mixed, the two tested routes of vector voltages are sent into the two A/D converters together and outputted to the ARM processor, and the ARM processor outputs and displays or sorts corresponding electric parameters. The LCR tester is an LCR tester, of which the frequency reaches MHz and the signal level step reaches 1mV, and the LCR tester can help to know the actual performance of elements under actual working conditions, and can enhance the performance and reliability of products.
Description
Technical field
The utility model relates to a kind of digital electric bridge, especially can adopt high-frequency signal source to measure the digital electric bridge of element under test, specifically a kind of LCR tester.
Background technology
LCR inductance (L), electric capacity (C) and resistance (R) are widely used in electronic product as basic components and parts.Along with the constantly development and improving of the technology of electronic product and performance, also in continuous raising, particularly the demand to components and parts parameter measurement under 1MHz and above frequency condition grows with each passing day domestic relevant industries to the requirement of the detection technique of components and parts.Therefore, frequency reaches the LCR tester that MHz, signal level stepping reach 1mV, helps to understand the actual performance of components and parts under actual operating conditions, improves performance of products and reliability.
Summary of the invention
The purpose of the utility model is the problem that the demand to the parameter measurement under 1MHz and above frequency condition of present components and parts grows with each passing day, and proposes a kind of LCR tester.The utility model is that frequency reaches the LCR tester that MHz, signal level stepping reach 1mV, helps to understand the actual performance of components and parts under actual operating conditions, improves performance of products and reliability.
The technical scheme of the utility model is:
A kind of LCR tester; It comprises reference clock, three the DDS signal sources, measuring transmitter, source resistance, the input circuit that is connected detected element, self-balancing bridge circuit, two filter, two frequency mixer, two A/D converters and the arm processor that link to each other with reference clock; The output of a described DDS signal source links to each other with the input end of measuring transmitter; The signal output part of measuring transmitter drives the detected element that input circuit connected through source resistance; Two measuring voltage ends of input circuit link to each other with a signal input part of respective mixers through wave filter respectively; Another signal input part of two frequency mixer all links to each other with the signal output part of the 2nd DDS signal source; The signal output part of two frequency mixer links to each other with the respective signal input end of two A/D converters respectively, and the signal source end of two A/D converters links to each other with the output of the 3rd DDS signal source, and the output of two A/D converters links to each other with the respective signal input end of arm processor; Arm processor links to each other with the respective signal end of LCD display, sorting interface, the corresponding electrical quantity of output detected element.
The one DDS signal source output signal frequency scope of the utility model is 20Hz～5MHz, resolution 0.01Hz.
The signal output part of the measuring transmitter of the utility model connects input circuit through source resistance behind concatenated filter, the power amplifier successively, drives detected element.
The detected element of the utility model links to each other to structure with one group of four end through input circuit.
The arm processor of the utility model links to each other with the respective signal end of memory cell, communication interface, keyboard.
The beneficial effect of the utility model:
The LCR tester of the utility model is that frequency reaches the LCR tester that MHz, signal level reach 1mV, helps to understand the actual performance of components and parts under actual operating conditions, improves performance of products and reliability.
Description of drawings
Fig. 1 is the theory diagram of the utility model.
Fig. 2 is the synoptic diagram of four ends to structure.
Embodiment
Below in conjunction with accompanying drawing and embodiment the utility model is further described.
As shown in Figure 1, the measuring transmitter of native system can produce the sinusoidal signal that frequency changes from 20Hz～5MHz (resolution 0.01Hz), amplitude from mVrms～5Vrms (1mV stepping), and-5V～+ the inside dc offset voltage of 5V.Test signal through one group of wave filter after, send into one the band automatic electric-level adjustment function (ALC) power amplifier amplify, go to drive detected element through source resistance again.Detected element links to each other to structure with one group of four end through input circuit, and self-balancing bridge circuit makes Lp hold virtual earth all the time, forms the two-way vector voltage.Tested two-way vector voltage is sent into two A/D converters together after filtering respectively, mixing.The A/D change-over circuit after digital processing, carries out vector voltage the real-time digital phase sensitive detection by arm processor and is divided into real part and imaginary part component, calculates different electrical quantitys such as Z, L, C, R at last and shows or sorting.
During practical implementation:
Testing source: the actual circuit condition of simulation when signal source is used to measure, the signal source of native system can produce the variable signal level of wideband, wide cut and step-length, and constant voltage, constant current function are arranged.Native system produces a clock reference by the crystal oscillator of 42.9497MHz, drives three DDS synthesized sources simultaneously, and three DDS synthesized sources provide corresponding data by arm processor and produce three different signal sources respectively.
The generation of test signal: the user is provided with the frequency and the level of test signal through control panel, provides corresponding data by arm processor, sends into the data input pin of DDS combiner circuit and D/A change-over circuit respectively, produces corresponding sinusoidal signal (Fc).Sinusoidal signal is sent into power amplification circuit after through low-pass filter, outputs on the detected element through output resistance again.
The generation of mixing reference signal: can reach 5MHz because the test frequency of native system is the highest; Therefore behind the frequency setting of test signal; Arm processor can be according to the difference of frequency test signal, and the DDS combiner circuit that control links to each other with the frequency mixer input end of clock becomes square wave through comparer and produces mixing reference signal Fr behind the frequency division again.Like this, tested vector voltage is through behind the frequency mixer, and its frequency finally becomes Ft (Ft=Fc-nFr, n are integers), and Ft is a sinusoidal signal that is not more than 1KHz.
The generation of sampled signal: after control panel is provided with the frequency of test signal; By arm processor according to the frequency (Fc) of test signal and weekly the sampling number (N) of phase (Tc) calculate the reference frequency (Fsr) of sampled signal; And provide corresponding data; Send into the data input pin of the DDS combiner circuit that links to each other with two A/D converter clock pins; The frequency signal of DDS combiner circuit output is sent into the clock pin of two A/D converters after comparer becomes square wave, generate final sampled signal Fs (Fs=N * Ft) by the inner logical circuit of A/D converter again.
Four ends are to structure: four ends are to structure (4TP) synoptic diagram; As shown in Figure 2; Four ends have solved problems such as mutual inductance coupling, stray capacitance, lead-in inductance, lead resistance to structure; Because it is isolated signal voltage path and current path with concentric cable, return current makes outer conductor (screen layer) offset the magnetic flux that inner wire produced through the screen layer of concentric cable.The measurement range of this configuration structure can reach more than the following 100M Ω of 1 Ω, in conjunction with the self-balancing bridge circuit method, can in 20Hz～5MHz, carry out precise impedance to it and measure.
Self-balancing bridge circuit: self-balancing bridge circuit comes parameters such as computing impedance through the voltage of measuring the Zx two ends and the electric current that flows through on the Zx.Hp end and Hc end are isolated each other, can accurately measure the voltage on the Zx like this.Electric current flows to the Lc end from Hc end, relies on a feedback control loop, makes the G point keep virtual earth and makes electric current flow through range resistance R s.Therefore, through measuring the ohmically voltage of range, can record the electric current that flows through on the Zx.
The A/D change-over circuit: vector voltage Vu and Vs can send into two A/D converters again, to eliminate the measuring error that is caused by passage at last simultaneously through two-way wave filter and the two-way frequency mixer by same reference clock control.Read Vu and the corresponding conversion value of Vs by the ARM microprocessor in real time from the A/D converter data terminal, carry out the real-time digital phase sensitive detection by arm processor and be divided into real part and imaginary part component.Through real component and the imaginary part component of voltage Vu and electric current Vs, the ARM microprocessor just can calculate a series of electrical quantitys such as equivalent series reactance or equivalent parallel reactance.
The utility model does not relate to all identical with the prior art prior art that maybe can adopt of part to be realized.
Claims (5)
1. LCR tester; It is characterized in that it comprises reference clock, three the DDS signal sources, measuring transmitter, source resistance, the input circuit that is connected detected element, self-balancing bridge circuit, two filter, two frequency mixer, two A/D converters and the arm processor that link to each other with reference clock; The output of a described DDS signal source links to each other with the input end of measuring transmitter; The signal output part of measuring transmitter drives the detected element that input circuit connected through source resistance; Two measuring voltage ends of input circuit link to each other with a signal input part of respective mixers through wave filter respectively; Another signal input part of two frequency mixer all links to each other with the signal output part of the 2nd DDS signal source; The signal output part of two frequency mixer links to each other with the respective signal input end of two A/D converters respectively, and the signal source end of two A/D converters links to each other with the output of the 3rd DDS signal source, and the output of two A/D converters links to each other with the respective signal input end of arm processor; Arm processor links to each other with the respective signal end of LCD display, sorting interface, the corresponding electrical quantity of output detected element.
2. LCR tester according to claim 1 is characterized in that a described DDS signal source output signal frequency scope is 20Hz～5MHz, resolution 0.01Hz.
3. LCR tester according to claim 1 is characterized in that the signal output part of described measuring transmitter connects input circuit through source resistance behind concatenated filter, the power amplifier successively, drives detected element.
4. LCR tester according to claim 1 is characterized in that described detected element links to each other to structure with one group of four end through input circuit.
5. LCR tester according to claim 1 is characterized in that described arm processor links to each other with the respective signal end of memory cell, communication interface, keyboard.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204943069U CN202330600U (en) | 2011-12-02 | 2011-12-02 | LCR (inductor-capacitor-resistor) tester |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011204943069U CN202330600U (en) | 2011-12-02 | 2011-12-02 | LCR (inductor-capacitor-resistor) tester |
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| Publication Number | Publication Date |
|---|---|
| CN202330600U true CN202330600U (en) | 2012-07-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011204943069U Expired - Fee Related CN202330600U (en) | 2011-12-02 | 2011-12-02 | LCR (inductor-capacitor-resistor) tester |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117269555A (en) * | 2023-09-22 | 2023-12-22 | 常州同惠电子股份有限公司 | Kelvin test multipath scanning automatic switching device and detection method |
-
2011
- 2011-12-02 CN CN2011204943069U patent/CN202330600U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117269555A (en) * | 2023-09-22 | 2023-12-22 | 常州同惠电子股份有限公司 | Kelvin test multipath scanning automatic switching device and detection method |
| CN117269555B (en) * | 2023-09-22 | 2024-06-11 | 常州同惠电子股份有限公司 | Kelvin test multipath scanning automatic switching device and detection method |
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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 |
Granted publication date: 20120711 Termination date: 20151202 |
|
| EXPY | Termination of patent right or utility model |