Learnto operatean impedanceMeter!Basic measurement methods
Overview
Impedance metersmeasure the amount of impedancealso known as resistance, toanAC.(AC). Thispage is a completeoutline of the fundamentals ofimpedance, the methods used to measureimpedance, and howto use an impedance tester.
What isimpedance?
Let’s begin by discussing the definition ofimpedance. Ina word, impedanceisa measurement ofresistance to theflowofanAC current.
When you connect an electricproduct, motororotherdevice toor from anACpower source,electricity will flowthrough thedevice’s circuitry. Impedance isdeterminedby dividing the voltage ofan AC circuit byits current. Insimple terms, impedance couldbedefined as limiting theflow of currentintheAC circuit. Impedance isrepresented bythesymbol “Z” and measured inOhms(O) this is the exactdevice used to measureDC resistance. Thegreater the impedancethegreater resistance is thereto theflow of current.
How can impedance be measured?
Since impedance itself is notan obvious phenomenon, it isimperative to use a measurementinstrumentin order to measureit. Instrumentsthat measurethe impedance of an object include impedance metersLCR meters as well as impedance analyzer. There area number ofways that impedance canbe measured.
Bridge method
Thismethod usesa bridge circuit in order to calculateanunknownresistance. It requiresbalance adjustment tobedone using a galvanometer.Even though the technique can providethe greatest degree of accuracy(about 0.1%), it’s poorly suitedto high-speed measurement.
I-V method
This methodcalculates the impedance by measuringthe voltagesthat cross a currentdetection resistor as well as an unknownimpedance. Itis also usedto testitemswho are grounded.When the impedance grows,themethod is more vulnerabletoeffects caused bythevoltmeter.
The RF I -V method
The method used isthe samebasic measurement principleas the I.V. method. Itpermits high-frequency impedance measurementby using a circuit whichis compatible with the characteristic impedance ofthe coaxial cable with high-frequency anda high-frequency coaxial connector.It’s challenging to employ thismethod to measure widebands becausethemeasurement frequency bandisrestrictedin the measurement head’s circuit.
Automatically balancedbridge method
This method uses the samebasic measurement method asthat of the bridge approach. Itgives coverage tothe entire frequency range(1100 MHz to mHz).But, itis not extended to higherfrequencies.A number ofLCR metersmake use of this technique.
Each impedance analyzer method has its ownadvantages and disadvantages, soyou must clearly definewhat kind of impedanceyou need to measurebefore choosing the bestmethod for you.
The use of an impedance gauge
The methodemployed to measure impedancewill depend on the measurement instrumentused.Like Hioki’s LCRMeter IM3523has the ability to measure impedanceat a high level ofaccuracy over a wide rangeoffrequency settings.
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40 Hz measurement
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200measurement in Hz
Apart from normal measurement This instrument can be used tocontinuously and quickly measure differentparametersin differentcircumstances(measurement frequency andsignal level).
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C-D+ESR Measurement of Capacitors
impedance analyzeris also able to savethe equivalent of 60 setsof measurement parametersalong with up to128correction values for open/short correctionandcable length correction.Sets of settings can beeasily loaded at onceto increaseefficiency.
Furthermore, the instrument’s externalcontrol terminalsmake it possible to constructautomatedtesting lines more quickly.
The causes of instability in impedancemeasurement
In accordance with the measurement methodin use, impedance metersmay return a different valueevery time a measurementtaken. Ifthemeasured values do not stabilize be stable, try the following methods:
Parasitic components of the components beingevaluated
Alongside the designvaluesfor resistivity and reactance,componentscan also be affected by parasitic elements thatcan cause a variance in measuredvalues.Thelength ofleads that connecttocomponents , and thedistance between themmaycause the measured values to differ.
Measurementof the environment
The measurement of impedance results can beaffected by manyconditions, includingvariations in temperature notonlyresistorsas well as capacitors and inductors as well asprobe capacitance as well as stray capacitance.
Thischaracteristic necessitates stepslike maintaining a uniformmeasurement environment , and also averaging multiplemeasurements instead ofrelying on a singlemeasurement tocalculatethevalue.
DC bias
DC biasis aminusculevoltage that can be found in measurementinstrumentsand circuits.For example, it occursin the case of wires and probes thatareconstructed from different materials. Thethermal electromotive force that resultscreatesDC bias.
Summary
Impedance quantifies resistance toan AC current, and itsmeasurement requiresan instrument that is specifically designed for.Since there are a varietyofmeasurement methods so it’s essential to pickthebest method based onyour needs and the method’sadvantages anddrawbacks.
Impedance measurement is verydelicate and is susceptible to variationsdue to various factors such asthe measurement environment, frequency andDC bias. Thismakes it necessary to performmeasures like averaging multiplemeasurements.
Applications
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The measurement of impedance for the 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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LCRmeter measurement principles
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How to Use an LCR Meter: Basic Knowledge