Learnto usean impedancemeasurer!Basic measurement methods
Impedance metersare used to measure the impedanceor resistance to the flow ofAC.(AC). Thispage provides a detailedoverview of the basics ofimpedance and methods of measuringimpedance and the best wayto use an impedance meter.
Let’s begin by discussing the definition ofimpedance. Ina word, impedanceisa measure ofresistance to thecurrentthroughanAC current.
When you connect an electricalproduct, motororotherelectronic device withor from anACsupply of power,current is able to flowthrough thedevice’s circuitry. Impedance isdeterminedby dividing the voltage inthe circuit byits current. Inessence, the term “impedance” canbedefined as a limit on theflow of currentwithintheAC circuit. Impedance isrepresented byusing thesymbol “Z” and measured inthe ohms(O) this is the exactmeasurement unit that is used to determineDC resistance. Thehigher the impedancethemore resistance there isto theflow of current.
How do you measure impedance?
Since impedance isn’tan apparent phenomenon, it’srequired to employ a measuringinstrumentto gaugeit. Instrumentscapable of measuringimpedance include impedance meters,LCR meters as well as impedance analyzer. There arenumerousmethods through which impedance maybe measured.
Thistechnique employsa bridge circuit in order to calculateanunknownresistance. It requiresbalance adjustment tobeaccomplished using a gaussometer.Although this method providesan excellent degree of accuracy(about 0.1%) but it’s not well-suitedto measurements with high speed.
This methoddetermines impedance by measuringthe voltagesacross a currentdetection resistor as well as an unknownimpedance. Itis also possibleto testany sampleswho are grounded.As the impedance increases,themethod becomes more vulnerabletoeffects caused bytheVoltmeter.
The method of RF I.V
The method used isthe samemeasurement principlessimilar to the I-V technique. Itpermits high-frequency impedance measurementwith a circuit thatmatches the characteristic impedance ofthe coaxial cable with high-frequency andcoaxial connectors with high frequency.It’s not easy to apply thismethod to measure widebands becausethefrequency band of measurementisrestrictedby the test head’s transformer.
Automatically balancedbridge method
This method employs the samefundamental measurement concept asit is based on the bridge principle. Itoffers coverage overthe entire frequency range(1mHz to 100 MHz).However, this coverageis not extended to higherfrequencies.A number ofLCR metersuse this technique.
Each impedance analyzer method has its uniquebenefits and disadvantages, and soyou’ll need to definethe type of impedance thatyou’ll need to gaugebefore choosing the bestmethod for you.
The use of an impedance gauge
The methodused to measure the impedancewill depend on the measurement instrumentused.For example, Hioki’s LCMeter IM3523can measure impedancewith greataccuracy across a wide rangeofmeasurementfrequency settings.
40 Hz measurement
In addition to standard measurement the instrument is able tocontinuously and quickly monitor differentparametersin variouscircumstances(measurement frequency andsignal level).
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impedance analyzercan also savethe equivalent of 60 setsof measurement conditionin addition to up to128correction values for open/short adjustmentandlength correction for cables.Sets of settings can bequickly loaded in one goto boostefficiency.
In addition, the instrument’s exteriorcontrol terminalslet you buildautomatedtesting lines more quickly.
Impedance measurement is unstable.measurement
Depending on the method of measurementin use, impedance meterswill return different valuesevery time a measurementconducted. Ifthemeasured values fail to stabilize be stable, try the following methods:
Parasitic components of the components beingassessed
In addition to the designvaluesfor resistance and reactance,componentsare also characterized by parasitic components whichcan cause a variance in measuredvalues.Even differences in thelength ofthe leads attachedtocomponents and in thedistance between themcancause the measured values to differ.
Impedance measurement results can beaffected by a variety ofconditions, includingthose of temperature, notjustresistors,as well as capacitors and inductors, as well asthe probe capacitance and stray capacitor.
Thischaracteristic necessitates stepslike maintaining a uniformmeasuring environment and averaging of multiplemeasurements instead ofusing just onemeasurement tocalculatethevalue.
DC biasor DC isvery smallvoltage that can be found in measurementinstrumentsand circuits.In particular, it occurswhen wire and probearemade from different substances. Thethermal electromotive force that resultscan causeDC bias.
The measurement of Impedance is based on the amount of resistance that exists toan AC current. Itsmeasurement requiresa specific instrument.Since there’s a myriadofmethods for measuring that you can choose from, it is important to selectthemost appropriate method based onthe goal you intend to achieve and also on each method’sadvantages anddrawbacks.
Impedance measurement is extremelydelicate and subject to variationdue to factors such asfrequency, measurement conditions, andDC bias. Thismakes it necessary to performprocedures like averaging severalmeasurements.
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