impedance analyzer – An Overview

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Learnhow to usean impedancemeasurer!Basic measurement methods

Overview

Impedance metersdetermine the level of impedancethat is, resistance or force to flowanalternating current(AC). Thispage provides a detailedreview of the basics ofimpedance, methods for measuringimpedance, and tips on howyou can use an impedance measurer.

What isthe definition of impedance?

We’ll begin by defining the termimpedance. Insimple terms, impedanceisa measure ofresistance to thecurrentfromAC current.AC current.

When you connect a electricproduct, motor,orothergadget toanyACenergy source,the current flowsthrough thedevice’s circuitry. Impedance isdeterminedthrough the division of the voltage inthis circuit byits current. Insimple terms, impedance couldbedescribed as limiting theflow of currentwithinanAC circuit. Impedance isrepresented byitssymbol “Z” and measured inOhms(O) which is the samemeasurement unit that is used to determineDC resistance. Thehigher the impedance,themore resistance there isto theflow of current.

How do you measure impedance?

Because impedance is notan obvious phenomenon, it isrequired to employ a measuringinstrumentto measureit. Instrumentscapable of measuringimpedance include impedance metersLCR meters and impedance analyzer. There aremanyways that impedance canbe measured.

Bridge method

Thismethod utilizesan abridge circuit to calculateanunknownresistance. It requiresthat balance adjustmentbemade using a galvanometer.Although this method providesan excellent degree of accuracy(about 0.1 percent) However, it’s unsuitedto measurements with high speed.

I-V method

This methodcalculates the impedance by measuringthe voltagesof a currentdetection resistor , and an unknownimpedance. Itis also possibleto determine the impedance ofany sampleswhich are ground.As the impedance increases,themethod is more vulnerabletoeffects caused bythevoltagemeter.

Method RF I-V

The method used isthe samebasic measurement conceptas the I.V. method. Itpermits high-frequency measurementthrough a circuit thatis compatible with the characteristic impedance ofcoaxial cables with high frequency andcoaxial connectors that are high-frequency.It’s difficult to use thistechnique to measure wideband impedance becausethefrequency range for measurementisrestrictedto the tester’s converter.

Automatically balancedbridges

This method employs the samefundamental measurement principle that is used inusing the bridge technique. Itcoverswide frequency bands(1from mHz up to 100 MHz).But, itdoesn’t extend to highfrequencies.A large number ofLCR metersutilize this method.

Each impedance analyzer method offers its ownadvantages and disadvantages, soit is essential to knowthe kind of impedanceyou’ll needprior to deciding on the most effectivemethod to employ.

By using an impedance meter

The methodemployed to measure impedancewill depend on the measurement instrumentemployed.For example, Hioki’s LCRMeter IM3523can measure the impedanceat a high level ofaccuracy across a wide rangeoffrequency settings.

  • 40 Hz measurement

  • 200milliseconds

In addition to standard measurement it can alsocontinuously and quickly monitor differentparametersin variouscircumstances(measurement frequency andsignal strength).

  • C-D+ESR Measurement of Capacitors

impedance analyzeris also able to saveup to 60 setsof measurement parametersin addition to up to128correction values for open/short correctionandcable length correction.A set of settings can beimmediately loadedto increaseefficiency.

In addition, the instrument’s externalcontrol terminalsmake it possible to constructautomatedtesting lines more quickly.

Causes of instability in impedancemeasurement

Depending on the measurement methodutilized, impedance metercan return a different numbereach time a measurement isconducted. Ifthemeasurements fail to maintain their stability be stable, try the following methods:

Parasitic components of the components beingassessed

In addition to the designedvaluesfor resistivity and reactance,componentsare also characterized by parasitic components whichcreate a range ofvalues.In addition, differences in thelength ofleads that connecttocomponents , and thedistance between themmaycause measurements to fluctuate.

Measurementof the environment

The Impedance measurement results areaffected by a range offactors, such asthat of the temperatures notonlyresistorsbut also capacitors and inductors, as well asthe capacitance of the probe and the stray.

Thisrequires stepslike maintaining a uniformmeasuring environment and averaging of multiplemeasurements instead ofusing onemeasurement todeterminetheamount.

DC bias

DC biasor DC issmallvoltage that is present in measuringinstrumentsand circuits.For instance, it happenswhen the probe and wirearemade from different substances. Thethermal electromotive force that resultsproducesDC bias.

Summary

Impedance determines the degree of resistance toan AC current, and itsmeasurement requiresa specific instrument.Since there are a varietyofmethods for measuring It is essential to choosethemost effective method, based onthe goal you intend to achieve and also on each method’sadvantages anddrawbacks.

The measurement of Impedance is verydelicate and subject to variationdue to a variety of factors, includingthe measurement environment, frequency as well asDC bias. Thisis why it is necessary to takemethods like averaging of multiplemeasurements.

Applications

  • The measurement of impedance for the Smart Key/Immobilizer antenna

  • MLCC

  • Conductive polymer capacitors

  • Tantalum capacitors

How to Use

  • LCRmeter measurement principles

  • How to Use an LCR Meter: Basic Knowledge

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