LCR - Inductance measurement

[Liam1980]

When I want to measure Inductance Through LCR



how do I know when use series & parallel mode


When I need to use in series



When I need to use in parallel



The have Scientific article on the subject ?


Thx

Liam

 

[stenzer]

Hi,

have a look here [1], its a quite helpful and comprehensive handbook regarding impedance measurements.

[1] https://www.keysight.com/de/de/assets/7018-06840/application-notes/5950-3000.pdf

BR

 

[KlausST]

Hi,

no scientific article needed.
It depends on your device (DUT). Or what you need to know.

Klaus

 

[FvM]

Series and parallel R are different equivalent circuits representing the same complex impedance measurement. You can convert one into the other.

 

[Externet]

The original post asks for measuring inductance and responses are shifted to impedance. Why ?

 

[stenzer]

Hi,

The original post asks for measuring inductance and responses are shifted to impedance. Why ?

impedance is the result of a real and imaginary part, where the real part is the resistance and the imaginary the reactance. If the inductance would be an ideal one, there would not be a real component and no use for a series or parallel representation. So finally it ends up in an impedance measurement.

BR

 

[KlausST]

Valid point.
But how do you measure inductance? Without impedance?

If the result shows 100% inductance - which in reality is imposiible - you don't care about series or parallel. The inductance value is the same for series and parallel.

But if the result not 100%, then there needs to be "something else" than inductance. Then you have complex impedance. Now it matters wheter parallel or series mode.

Klaus

 

[Externet]

Seems to me the original poster wants to learn when to use the "parallel" or the "series" measurement mode for an inductor probed by a LCR meter.

Text of an Amazon product (violet) says :

UT611/UT612LCR meter is a more advanced meter used to measure inductance, capacitance and resistance. Advanced features include series/parallel measurement modes, quality factor/loss/phase angle measurements, equivalent/DC resistance measurements and 5 kinds of measurement frequency in AC mode for selection. UT612 can be easily operated in production lines, component inspection and electronic maintenance.
( https://www.amazon.com/UNI-T-Interface-Measurement-Multimetro-Inductance/dp/B0B87ZHWRR )

It may be interpreted as measuring the inductance by probing two or more inductors connected in parallel ; or two or more inductors connected in series.
And adding, which (internal?) meter frequency to use and when for measurements available by the instrument should be selected.

Test frequency	100Hz/120Hz/1kHz/10kHz100kHz

 

[KlausST]

Hi,

There´s nothing wrong with this Amazon text.
But generally I don´t recommend to learn from "advertising sites". They are often wrong, incomplete or at least rather "selling" focussed.

Instead I recommend to use semiconductor manufacturers, universities or professional sites.

I did not think about two inductors in series or parallel. Indeed the LCR meter will always see the resulting inductance and can not differ between the two inductors.

Usually
* "series mode" with LRC measurement means: L (C) and R in series.
* "parallel mode" with LRC measurement means: L (C) and R in parallel.
The meter just sees the voltage, current and the phase shift. And it needs the user information (ser/par) to calculate the correct L and R values.
(Because they differ in series and parallel mode)

Klaus