Learnto usean impedancemeasurer!Basic measurement techniques
Overview
Impedance metersmeasure the amount of impedancethat is, resistance or force to flowanAC.(AC). Thispage offers a thoroughoverview of the basics ofimpedance, the methods used to measureimpedance, and tips on howyou can use an impedance measurer.
What isthe definition of impedance?
Let’s begin by discussing the definition ofimpedance. Inshort, impedanceisa quantity that expressesresistance to theflowinAC current.AC current.
If you connect an electricproduct, motor,orany otherdevice toor from anACelectricity source,the current flowsthrough thedevice’s circuitry. Impedance isdeterminedby dividing the voltage ofsuch a circuit byits current. Inessence, the term “impedance” canbedescribed as limiting theflow of currentinanAC circuit. Impedance isrepresented bythesymbol “Z” and measured inOhms(O) that is the sameunit that measuresDC resistance. Thehigher the impedancethemore resistance there isto theflow of current.
How is impedance measured?
Because impedance is nota visible phenomenon, it’snecessary to use a measuringinstrumentin order to measureit. Instrumentsthat measureimpedance include impedance meters,LCR meters and impedance analyzer. There arenumerousmethods that allow impedance tobe measured.
Bridge method
Thismethod employsan abridge circuit to calculateanunknownresistance. It requiresthat balance adjustmentbecarried out using a galvanometer.Although the technique providesa high degree of accuracy(about 0.1 percent) It’s not the best suitedfor high-speed measurements.
I-V method
This methodcalculates impedance usingthe voltagesof a currentdetection resistor and an unspecifiedimpedance. Itcan also be usedto determine the impedance ofitemswhich are ground.As the impedance increases,thetechnique becomes increasingly susceptibletoeffects caused bythevoltmeter.
The method of RF I.V
This method employsthe samemeasurement principlessimilar to the I-V technique. Itallows high-frequency impedance measurementwith a circuit thatcorresponds to the characteristic impedancea high-frequency coaxial cable andan high-frequency coaxial connector.It’s not an easytechnique for wideband measurement becausethefrequency range for measurementislimitedthrough the tests head’s transistor.
Automatically balancedbridges
This method employs the samefundamental measurement concept asthat of the bridge approach. Itoffers coverage overan entire frequency range(1from mHz up to 100 MHz).However, the coveragedoes not extend to highfrequencies.A large number ofLCR metersutilize this method.
Each impedance analyzer technique has its ownadvantages and disadvantages. Therefore,you’ll need to clearly definewhat kind of resistanceyou’ll need to testprior to deciding on the most effectivemethod for you.
Utilizing an impedance meter
The methodused to measure impedancedepends on the instrument beingemployed.For example, Hioki’s LCRMeter IM3523measures impedanceat a high level ofprecision over a large rangeoffrequency settings.
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40 Hz measurement
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200measured Hz
In addition to the normal measurement This instrument can be used tocontinuously and quickly measure differentparametersin variousconditions(measurement frequency andsignal level).
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C-D+ESR Measurement of Capacitors
impedance analyzeris also able to saveas much as 60 setsof measurement conditionor up-to128value of corrections for open/shortandlength correction for cables.Sets of settings can beeasily loaded at onceto boostefficiency.
Additionally, the instrument’s externalcontrol terminalsmake it possible to constructautomatedtesting lines more quickly.
Causes of instability in impedancemeasurement
Depending on the method of measurementemployed, impedance meterscan return a different numbereach time a measurement istaken. Ifthemeasured values fail to stabilize then check the following:
Particular components with parasitic properties of the component beingevaluated
In addition to the designedvaluesfor resistance and reactance,componentsalso have parasitic components thatcan cause a variance in measuredvalues.There are also variations in thelength ofleads that connecttocomponents as well as thedistance between themmaycause measured values to vary.
Measurementenvironmental
Impedance measurement results can beaffected by manyconditions, includingtemperatures ofonlyresistors,but also inductors and capacitors, as well asthe probe capacitance and stray capacitor.
Thisrequirement requires actionssuch as maintaining a consistentmeasurement space and averaging severalmeasurements instead ofusing a singlemeasurement todeterminethevalue.
DC bias
DC biascan be described as asmallamount of voltage present in measuringinstrumentsand circuits.For instance, it happenswhen wires and probesareconstructed from different materials. Theresulting thermal electromotive forcecreatesDC bias.
Summary
Impedance measures resistance toan AC current. Itsmeasurement requiresan instrument that is specifically designed for.Since there’s a myriadofmeasurement methods and methods, it’s crucial to pickthebest one based onyour requirements and each technique’sadvantages anddrawbacks.
Impedance measurement is verydelicate and prone to fluctuationdue to factors includingfrequency, measurement conditions as well asDC bias. Thischaracteristic requiresprocedures like averaging severalmeasurements.
Applications
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Impedance measurements of Smart Key/Immobilizer antenna
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MLCC
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Conductive polymer capacitors
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Tantalum capacitors
How to Use
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LCRPrinciples of measurement for meter
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How to Use an LCR Meter: Basic Knowledge