Science topic

# Impedance - Science topic

Explore the latest questions and answers in Impedance, and find Impedance experts.
Questions related to Impedance
Question
Is there a simple way to calculate the impedance of a coplanar Vivaldi antenna?
1- Characterization of Printed Podal Vivaldi Antenna (8–18 GHz) on RT Duroid with Single and Double Cavity.)
Question
Hi,
I simulated an antenna with a matching network. Now to calculate the antenna range using Friis equation I need to know the losses due to the matching network.
Can anybody suggest how can I find the losses due to the matching network? I prefer to use software.
There are two components. Power loss due to power reflected back to the source and absorbed by the source (1-|S11|²) and loss in the matching circuit itself due to dissipation by the non-ideal reactive components.
Question
I run an impedance test with mild steel coated with polymer coating. The impedance is showing very abnormal pattern as shown in the pic. On the other hand, when I was running the same Nyquist test with stainless steel it is showing quite a normal graph. Can someone suggest me the real reason why the impedance data is showing very abnormal reading. Thank you.
Working electrode : Polymer coated mild steel sample.
Reference : Saturated calomel electrode
Counter : Graphite counter electrode
What kind of organic coating and electrochemical set up do you use. I think that you have a problem with parameters of your set-up - a high impedance of coating and small impedance od EIS apparatus.
stefan
Question
SIL is define as when transmission line loaded with Impedance equal to its Surge Impedance ignoring Resistance and conductance. When Surge impedance is equal to load impedance the sending end and receiving end voltages are equal.
Standing waves can occur in transmission lines at power system frequency under certain conditions. When a voltage wave travels along a transmission line, it encounters a load impedance at the end of the line. If the load impedance is not matched to the characteristic impedance of the line, a portion of the voltage wave is reflected back towards the source. This reflected wave can then interfere with the original wave, resulting in the formation of standing waves.
The formation of standing waves in a transmission line is influenced by various factors, including the length of the line, the characteristic impedance of the line, the load impedance, and the frequency of the voltage wave. In particular, the relationship between the load impedance and the surge impedance of the line can affect the likelihood and severity of standing waves.
The surge impedance of a transmission line is the characteristic impedance of the line when it is assumed to be infinitely long. When the load impedance of the line matches the surge impedance, there is no reflection of the voltage wave, and standing waves do not occur. However, if the load impedance is higher or lower than the surge impedance, some of the voltage wave is reflected back, leading to standing waves.
In summary, standing waves can occur in transmission lines at power system frequency, and the relationship between the load impedance and the surge impedance of the line can affect their formation.
Question
Battery impedance is a combination of internal resistance and reactance where internal resistance + reactance, or (L+ C), equals impedance when using an ac stimulus. The internal resistance of a battery is made up of two components: electrical, or ohmic, resistance and ionic resistance.
Impedance is measuring the overall health and performance of the battery. It can detect battery degradation, abnormal conditions, and aging to ensure proper maintenance and extend battery life. It helps monitor the battery's state of charge and capacity loss.
Question
I face a very lossy line (cryogenic harness) with L = 320 nH/m, C = 60 pF/m and R = 10Ω/m characteristics. I can estimate the characteristic impedance of this transmission line as Z0=√L/C~70Ω. with 2 meters length, the lossy part is about R = 20 Ω. My simple question, is, if I want to amplify the end of this line with a good input matching, what LNA input impedance have I to match ? Z0 line impedance ? Z0 "+" R line impedance "+" resistance? Source impedance Rs? Source impedance Rs + losses R?
Hello! The expression √(L/C) is correct just for the determination of the characteristic impedance of lines with negligible losses. Try to use a complete formula that contains also dissipative parameters.
Question
Dear All,
I wonder if someone can give a clue on how to do fitting if, in a high-frequency region, there is a kind of hook. Please find the files attached. The system is a water-soluble biopolymer in buffer solution, liquid EIS, electrodes: Carbon (WE), Ag/AgCl (RE), and Pt wire (CE). OCP. I've got minimum errors at using this equivalent circuit.
Thanks!
fitting(s) follow the (good) data.
So, try to reduce the AC-amplitude (VAC<5mV) and remeasure, in order to reduce the high-frequency 'hook'-error(s).
1. A cart follows the horse, or 'A horse pulls a cart (not the opposite)'.
Question
Dear RG community members, this pedagogical thread is related to the most difficult subject among the different fields that physics uses to describe nature, i.e. the physical kinetics (PK). Physical Kinetics as a subject is defined as a “method to study physical systems involving a huge number of particles out of equilibrium”.
The key role is given by two physical quantities:
• The distribution function f (r, p, t), where r is a vector position, p is a linear momentum and t is the time for the function f which describes a particle in an ensemble.
• The collision or scattering term W (p, p¨) gives the probability of a particle changing its linear momentum from the value p to the value during the collision.
If the following identity is satisfied for the distribution function df (r, p, t) / d t = 0, then we can directly link PK to the Liouville equation in the case that the distribution function does not depend on time directly. Physics students are tested on that, at the end of an advanced course in classical mechanics, when reading about the Poisson brackets.
However, is important to notice that not all phys. syst. are stationary and not always the identity df /d t = 0 follows, i.e., the distribution function - f is not always time-independent, i.e., f (r, p) is just true for some cases in classical and non-relativistic quantum mechanics, and the time dependence “t” is crucial for the majority of cases in our universe, since is out of equilibrium.
In addition, physical kinetics as a “method to study many-particle systems” involves the knowledge of 4 physics subjects: classical mechanics, electrodynamics, non-relativistic quantum mechanics & statistical mechanics.
The most important fact is that it studies the scattering/collision of particles without linear momentum conservation p, where: the time dependence & the presence of external fields are crucial to study any particular physical phenomena. That means that PK is the natural method to study out of equilibrium processes where the volume of the scattering phase space is not conserved & particles interact/collide with each other.
If the phase scattering space vol is not conserved, then we have the so-called out of equilibrium distribution function which follows the general equation:
df (r, p, t) / d t = W (p,p¨), (1)
where: d/dt = ∂/∂t + . ∂/∂r + p´. ∂/∂p, with units of t -1or ω/(2π).
The father of physical kinetics is Prof. Ludwig Eduard Boltzmann (1844 – 1906) . He was able to establish the H theorem which is the basis for the PK subject and also he wrote the main equation (1), i.e., the Boltzmann equation to describe the out of equilibrium dynamics of an ideal gas. & in d/dt are derivatives, p¨ in W is another momentum position
Another physicist who established the first deep understanding and condensed the subject into a book was Prof. Lev Emmanuilovich Gurevich (1904 - 1990). He was the first to point out that the kinetic effects in solids, i.e., metals and semiconductors are determined by the "phonon wind", i.e., the phonon system is in an unbalanced state 
Physical kinetics has 3 main approaches:
• The qualitative approach involves the evaluation of several physical magnitudes taking into account the order of magnitude for each of them.
• The second approach is the theoretical approach which involves complicated theoretical solutions of the kinetic equation using different approximations for the scattering integral such as the t approximation. For graduate courses, I follow , an excellent textbook by Prof. Frederick Reif. For undergraduate teaching, I followed the brief introduction at the end of Vol V of Berkeley Phys C.
• The numerical approach since most problems involving PK requires extensive numerical and complicated self-consistent calculations.
The fields where PK is useful are many:
• The physics of normal metals and semiconductors out of equilibrium.
• The hydrodynamics of reacting gases & liquids, quantum liquids, and quantum gases at very low temperatures.
• The physics of superconductors, phase transitions, and plasma physics among others.
There is a quantum analog to the classical Boltzmann equation, we ought to mention three cases: the density matrix equation for random fields, the density matrix equation for quantum particles, and the Wigner distribution function. Main graph 1 is adapted from  to the English language, LB picture from , and LG picture from .
Any contributions to this thread are welcome, thank you all.
References:
2. Fundamentals of physical kinetics by L. Gurevich. State publishing house of technical and theoretical literature, 1940. pp 242
3. Lev Emmanuilovich Gurevich. Memories of friends, colleagues, and students. Selected Works, by Moisey I. Kaganov et. at (1997) pp 318. ISBN:5-86763-117-6. Publishing house Petersburg Institute of Nuclear Physics. RAS
4. Белиничер В.В. Физическая кинетика. Изд-во НГУ.Новосибирск.1996.
5. Lifshitz E., Pitaevskii L. 1981. Physical Kinetics. Vol. 10, (Pergamon Press).
6. Thorne, K. S. & Blandford, R. D., Modern Classical Physics: Optics, Fluids, Plasmas, Elasticity, Relativity, & Statistical Physics (2017) (Princeton University Press).
8. Fundamentals of Statistical and Thermal Physics: F. Reif Mc Graw-Hill, 1965
Yes, Prof. Zachary Knutson, you are right. Perturbation theory works sometimes, but we must agree that there is not a unique approach to solving the kinetic equation.
I apologize for the late reply.
The reason why perturbation does not work always is that there are many physical phenomena that involve processes out of equilibrium with chaoticity and randomness, in addition to.
• Nonlinearity.
• Self consistency.
• Many bodies.
• Scattering involving those many bodies
So sometimes if the problem can be linearized, then perturbation can be used, but sometimes.
Let us see, for example, superconductivity by only considering the T different from the 0 K case (Matsubara frequencies is usually and correctly named) and only taking into account the first term in the zero temperature energy gap (that takes into account self-consistency, or another example is the Vlasov equation in the case of linearization for plasmas is a wonderful example of linearization where perturbation theory applies as you stated.
Best Regards.
Question
What will be the equivalent electrical circuit of the following set of multiplied and divided impedances:
Z1 / (Z2 x Z3)
It is assumed that each of these impedances itself represents an element or electrical circuit.
It seems from your answers that this kind of impedance combination is rather specific to the electrical engineering field. Am I right or are there applications in other scientific fields, especially in electrochemistry and electrochemical impedance spectroscopy (EIS)?
Question
Hi, I was measuring the impedance of carbon materials for ORR using a three electrode apparatus with Hg/HgO as reference. The frequency was 10^6 to 0.1Hz, similar to the literature. However, the measured Nyquist plot was quite strange where at high frequency, the imaginary part was not zero. (it only shows half of the first semi-circle).
Does anyone know the reason for that? Another question is, based on this Nyquist plot, how can define the uncompensated resistance of my data?
I`ve attached the screenshots of both Nyquist and Bode plot here.
Thank you very much for answering/suggestions!
Thank you both. Yes, I agree it came from the instrument. In our case, the electrode we use cannot respond with high frequencies.
Question
I've included an example picture. Is this transition followed by Quarter Wave transfer rules? or, Can anyone assist me in properly identifying this transition section?
You should know that this is not governed by quarter wave transition rules. A quarter wave transformer transforms between two different impedances not two impedances that are the same. The flare will introduce an effective lumped capacitance at the join and may be to compensate for other parasitic inductance or capacitance at the transition.
It probably isn't, but it may just be a badly designed transition. Not everything in published papers is good, especially if that wasn't the main point of the paper.
Question
I want to deposit silver nanoparticles on glass substrate by thermal evaporation technique.what values of the parameter (accostic impedence,density,thickness) i should take.
Can anyone please provide density and accoustic impedance of CZTSe compound.
Question
I would like to simulate the concrete bar on COMSOL to obtain the electrical properties such as capacitance, permittivity as well as impedance in order to measure the porosity and moisture of the concrete.
The image contains a concrete bar with 2 electrodes (on the top), which is a kind of capacitive device. I would like to obtain the best electrode size and shape.
Which electrical properties (or parameters) are required to investigate the best electrode size and shape for the capacitive device? How to optimize the distance between the electrodes on COMSOL?
Ítalo César Porto Xavier Thank you very much for sharing the docs.
Question
Nyquist plots for the supercapacitors
with PK and PKF4 gel polymer.
These other papers could be useful for you:
Best,
Fran
Question
Currently, I am performing electrochemical analysis on screen sprinted gold electrodes and extracting Impedance and CV curves. I am new to this field. From the literature, I read that charge transfer resistance is a combined effect of resistance and capacitance. I need only the resistance component. Is there a way to extract it?
It sounds like you want a single value to assign to resistance of the electrode, to simplify your analysis. If this is your intent, then my answer is no: that would oversimplify the system, and you would be ignoring important changes at the interface if you took that approach.
That said, there is a way used by most experimentalists to avoid the complexity of impedance and the likely confounders such as side reaction products with your electrolyte. I don't recommend this, since it often produces poor quality research. However, if someone is pressuring you to generate results that match those in other publications, the solution is to fit your EIS data to an equivalent circuit - R(RC) is popular but R(C[RW]) is more likely to match your pristine gold electrode - and ignore all data except the value fitted by your software to the last resistor, which is often called charge transfer resistance. This means your research will be dependent on the algorithm used by one proprietary fitting program, you won't know if the circuit is an appropriate one for your system, and you'll be hiding behind the poor practice repeated by others. Best of luck.
Question
I am trying a THz absorber for which help is required
HFSS does not use B and D field data, so there is no way to calculate permeability, and permittivity. You can only define these.
I guess, your question is related to troubleshoot the data fetched by HFSS from Maxwell? It always creates many doubts since the results sometimes are bizare, and the thing is almost not documented. Unit conversion is often incorrect, and I would also check these parameters. But do not know how.
Question
Hi Experts,
Is there any other electrochemical techniques or approach, except EIS, to determine the charge transfer resistance?
I appreciate it if you have any idea. Thank you
Regards,
Mohin
Dear Mohiedin. You may also try to use the Butler-Volmer equation, but neglect the exchange current because you are working in an area far from equilibrium
Question
I designed a antenna working at MHz range. I got -10 db impedance bandwidth for certain range of frequencies. In that range of frequencies I got a spike in impedance bandwidth for -2db. I tried reducing it. Can somebody help me on how I can approach this problem
Hello,
impedance matching is the practice of designing the input impedance of an electrical load or the output impedance of its corresponding signal source to maximize the power transfer or minimize signal reflection from the load.
Some papers are attached.
Thanks,
Question
I need to verify the results of the classical PEC or İmpedance half plane results obtained by the theory of Physical Optics by using HFSS or CST.
I attached the figures of the geometry and the total wave result for the incident wave angle of 60°, the total wave (=incident wave+geometrical optical wave+diffracted wave) and
diffracted wave in MATLAB.
How can I verify it in HFSS or CST or any suggestion?
Are you plotting the fields at a particular distance from the edge, or are these normalised far-field results? They look to me like the far-field scattering from the 50 wavelength square plate. I assume the plate is not 50 wavelengths square at 1, 2, and 3 GHz, but only at one of them, perhaps 3 GHz.
It is not possible to plot the far-field of a plane wave - it is a delta-function, so what you have is the polar diagram of the reflected wave, centred about 120 degrees, the polar diagram of the shadow the plate makes in the plane wave (see Babinet's principle), centred about 240 degrees, and low-level diffraction between these angles, and outside them too, but not so much.
I think your initial GO and GTD result (not PO) that you are trying to verify is in the near-field. The near-field for an infinitely long edge on a semi-infinite half-plane extends out to infinity.
Question
The EIS measurements often require the conditions of stable state for batteries. So the perturbation signals for EIS measurement are low, such as 5-10 mV for the perturbation voltage. However, the EIS measurement time is usually long, such as 10 min or even 30 min. In this case, the battery may not locate at stable states. For example, the battery temperature or SOC is changed. Thereby, the measured EIS under the unstable state is not the true EIS at the setting point. Exactly, many factors would influence the EIS measurement. Which one is dominant? Which one is inherent?
It was not possible to find this equation: "... the capacity change should be I/w*(1-cos(wt)).", in your existing paper. Maybe, It will be shown in your next, paper, plans.
Question
I want to find the resonance and anti-resonance frequencies of an ultrasonic transducer by analyzing its impedance.
so I need to buy a impedance analyzer or spectrum analyzer or something like that.
but my budget is limited.
do you recommend any device for my application and limited budget? :D
If you want to measure impedance in a low cost way, get yourself
1) Suitable signal generator
2) An appropriately sized current sense transformer
3) a two-channel oscilloscope.
Measure the voltage and current as you vary frequency. Oscilloscope will give you the phase relationship between current and voltage across transducer. You can then calculate the real and imaginary components of impedance. I leave it as an exercise how you might calibrate this setup. Cheers!
Question
Hello,
I'm designing a CPWG in the 30 GHz range in HFSS. I noticed that in my design the characteristic impedance is variable across my simulation range from 15-50 GHz. I think this is to be expected but more importantly the impedance of the line seems to be quite sensitive to the port definition. If I use the suggested wave port width the port overlaps with the coplanar grounds and the impedance drops from 52 ohm to 14 ohm. Any suggestions or tips on how to accurately do this and ensure no artifacts from the wave-port definition?
In CST it is possible to look at the port mode fields that have been calculated. It probably is in other codes. Keep making the port bigger until the fields stop spreading wider when you make the port bigger. Also keep making it bigger until the port impedance stops changing.
Question
is it possible to make a DIY impedance analyzer for checking the resonance frequency of high power ultrasonic transducers? for example a face mask welding ultrasonic transducer
Yes, it is possible.
The most straightforward way is through Ohm’s Law. By using a voltage sensor to measure the test signal's voltage across the transducer and using a current sensor to measure the test signal's current flowing through the transducer, together with various signal processing algorithms, the impedance over the frequency range of interest can be obtained. The test signal can be produced by a signal generator. As an alternative, you also can use the Inductive Coupling Method for the measurement of the impedance of the transducer. More information about these methods have been detailed in my following papers/monograph:
 Z. Zhao, "Measurement setup consideration and implementation for inductively coupled online impedance extraction," Ph.D. thesis, Nanyang Technological University, Mar. 2021, doi: 10.32657/10356/146738.
 Z. Zhao, A. Weerasinghe, Q. Sun, F. Fan, K. Y. See, "Improved calibration technique for two-probe setup to enhance its in-circuit impedance measurement accuracy," Measurement, 2021, vol. 185, Art no. 110007.
 A. Weerasinghe, Z. Zhao, N. Narampanawe, Z. Yang, T. Svimonishvili, K. Y. See, "Single-probe inductively coupled in-circuit impedance measurement," IEEE Trans. Electromagn. Compat., 2021, doi: 10.1109/TEMC.2021.3091761.
Question
I am simulating a power converter circuit on Simulink platform. This also include a 400 V AC grid. I am not sure about a generic thumb rule to define the impedance of the cables for this 3ph 400V Grid system. Any suggestions?
As an alternative, you can measure the grid impedance for the 400 V AC system directly. Please check our below publications for in-circuit impedance measurement:
 Z. Zhao, "Measurement setup consideration and implementation for inductively coupled online impedance extraction," Ph.D. thesis, Nanyang Technological University, advised by Prof. Kye Yak See, Mar. 2021.
 Z. Zhao, K. Y. See, E. K. Chua, A. S. Narayanan, W. Chen, and A. Weerasinghe, "Time-variant in-circuit impedance monitoring based on the inductive coupling method," IEEE Transactions on Instrumentation and Measurement., vol. 68, no. 1, pp. 169-176, Jan. 2019.
 Z. Zhao, K. Y. See, W. Wang, E. K. Chua, A. Weerasinghe, Z. Yang, and W. Chen, "Voltage-dependent capacitance extraction of SiC power MOSFETs using inductively coupled in-circuit impedance measurement technique," IEEE Transactions on Instrumentation and Measurement, vol. 61, no. 4, pp. 1322-1328, Aug. 2019.
 Z. Zhao, A. Weerasinghe, Q. Sun, F. Fan, K. Y. See, "Improved calibration technique for two-probe setup to enhance its in-circuit impedance measurement accuracy," Measurement, 2021, vol. 185, Art no. 110007.
 A. Weerasinghe, Z. Zhao, N. Narampanawe, Z. Yang, T. Svimonishvili, K. Y. See, "Single-probe inductively coupled in-circuit impedance measurement," IEEE Transactions on Electromagnetic Compatibility, 2021, doi: 10.1109/TEMC.2021.3091761.
Question
For my research on inkjet-printable electrodes, I want to compare the capacitance/impedance of a parallel-plate capacitor with a planar interdigitated capacitor.
In order to verify my simulation results, I additionally want to calculate the capacitance/impedance of the interdigitated electrodes analytically, dependent on geometry and material properties.
Can somebody provide some formulas and/or respective source where I can find how to calculate such a structure?
Are you comparing a parallel plate electrochemical capacitor to an interdigitated one of the same materials/chemistry? In that case, you probably already know to use EIS to quantify capacitance using an equiv. circuit model. However, the geometry will give you substantial differences because of edge effects. Each corner of the interdigitated electrodes will cause a distortion of the stored field, so if you're looking for solutions in lit, try searching the term "edge effects".
Question
Can somebody suggest me on why to find the impedance of the antenna after designing in a software then how to know whether to use impedance matching or quater wave transformation or impedance transformer etc so that the gain can be increased.
Hi
For wave port, the impedance will calculate automatically using the actual port impedance you have for your structure so no need to renormalize and this usually what you have because in practice this will be the situation.
Question
I have designed a split ring resonator with a metal ground so my S21 is zero. How can I plot the permittivity and permeability and impedance in HFSS?
Since I have used metal ground I also can't find the phase of S21.
INVESTIGATION OF EFFECTIVE PERMITTIVITY AND PERMEABILITY FOR A NOVEL V-SHAPED METAMATERIAL USING SIMULATED S-PARAMETERS
Question
Hi all, I get my admittance data using Impedance Analyzer for the PZT transducer attached to a plate. I measure three times with 15 minutes interval on the first day (fig.1) and then measure three times with 15 minutes interval the next day (fig.2). The obtained curves are different in the same day and also in the different day (fig.3).
I read papers but cannot find how to explain this phenomenon. From the theoretical expression of admittance or impedance, it seems the capacitance of PZT contributes to this difference, if my guess is right, why the capacitance of PZT varies everyday? (The temperature are 25 ℃ with +/- 3℃). Could anyone help to give any hints or references about this? Thanks.
Robert Lirette ,Hi Robert, thanks for the reply. I do optimize my circuit based on your reply. It helps. So now I can obtain the same results within the same day. But I still get different curves measured at different days. I am trying to find the factors. Thanks again.
Question
Please explain VersaSTAT MC Multi channel electrochemical system with details regard handling of software for a VersaSTAT Studio, please how/where to set potential window value and Where to set the Current Density value (1A, 2A, 3A or mA) into Charge-Discharge in order to supercapacitor form a charge discharge experiment.
Using VersaSTAT chronopotentiometry, what is the procedure of cyclic charge discharge method procedure step wise, 1) where to set applied potential and current density value (A or mA). CV and Impedance much better.
Please anybody help me how to what is the procedure using in (VersaSTAT Studio) software chronopotentiometry charge discharge options and settings.
please mention references for the same.
Thirumal Vediyappan I am able to do what you are asking for. You are looking to run a Cyclic Charge Discharge (CCD) at constant current between your intended voltage range for a supercapacitor.
The way you do this on VersaSTAT is as follows:
Open a new experiment and in the experiment properties window (where it says actions to be performed) insert Chronopotentiometry. In the properties for chronopotentiometry use the current value you need and in the scan properties use data resolution (eg. time per point (s) = 0.001) and duration (eg. 200 s). In the limits use potential (eg. potential >=1 for aqueous capacitor or >= 2.7 or 3.0 V for non-aq capacitor). Then insert another Chronopotentiometry step, this time use a negative current (for discharge) and use same scan properties and put the voltage limit to <=0.
Now press shift and select both Potentiometry steps and keep pasting below. I typically do it 5 times (5 charge and 5 discharge steps).
Screenshot attached. Please let us know if this works?
Question
Recently, I'd like to collect some formulas for some specific transmission line structures in PCB (single-ended stripline, single-ended microstrip line, etc)
I found that there is no formula related to the impedance of the microstrip line with solder mask (the region above the solder mask treated as the vacuum or the air)
Is there any suggestion to find that?
In this case case I would go for a numerical evaluation which is rather easy these days..even if there is a formula somewhere it will be an approximation and not straightforward to solve
Question
Hi!
I am trying to understand impedance spectroscopy for resistive switching studies. I am wondering what would be the best resource to start.
Thanks a lot
You can follow this review article for resistive switching and their measurements like Impedance Spectroscopy
Question
With Regards,
I have designed a patch antenna in HFSS for 2.45GHz.
S11 is around -44
Impedance 49.6+0.46j
But the problem is with gain which in -ve in dB scale.
I could not understand why? What may the reason for that?
Can someone help me?
I am attaching the plot for your referance.
Thanks
Just because something is resonant and matched does not mean it will radiate. A resonant cavity can be matched, and will not radiate. However, it may be that your antenna is radiating and you are looking in the wrong direction or at the wrong polarization.
Question
Dear Researchers,
I am working with a Silicon Substrate based sensor and getting CV curve with Initial and Low voltage -0.2V and High voltage 0.4. However, in the EIS test, the Nyquist plot is not giving the circular shape it's supposed to give at the beginning. I am using CHI660E and in A.C. Impedance test, do I need to set the peak voltage at which I am getting the oxidation peak? Also what should be the voltage range of CA depending on the CV parameters? Your help would be really appreciated.
The current in the electrochemical electrodes are composed of the following current components:
- The displacement capacitive current due to due to the electrode electrolyte capacitance
- The conduction current due to the charge transfer to the surface of the electrode.
If you scan the voltage you will have displacement current because such current is proportional to dV/dt.
If you measure your electrode under static conditions you will get only the charge transport current only.
The third current may be a form of interference or man made noise current because the impedance of the electrode is high in the range of the measurement.
I see that the if you increase the voltage further the current will increase appreciably pointing out the onset of the electrochemical reactions.
The other thing is that the rapid increase and fall with the voltage may be due to
some form of interference or noise or contaminated chemicals.
For typical electrochemical electrodes performance for water analysis please see the paper in the link:
Best wishes
Question
One of my colleagues said, "the impedance you can measure with the three electrodes and with the specific sequence varying the frequency"
Is it possible to configure the potenciostat without the FRA module, with these settings? If so, how could I do that?
Years ago I usually did that using an analogue potentiostat, a function generator and a plotter to draw the E/I Lissajous pattern for each frequency. Today you can use a data acquisition card to do the work: polarizing the cell through the potentiostat and recording the E/I output.
Question
I am trying to plot a surface impedance of a metal patch vs patch dimension (square patch). I have designed a unit cell consisting of a grounded substrate, a patch on the top of substrate, master/slave BCs on the four sides of my unit cell and a Floquet port on the top.
For some reasons that i don't really know, I can't obtain the expected results .
Please could someone help me find out what I am doing wrong?
Use the De-embedding at the surface of the structure for getting the correct results.
Question
How can I fix the port impedance in HFSS for an RFID Tag? In my simulation I always take it the conjugate of the Chip impedance but I never validate it by the measurement. I want to know if there is some other method to fix the port impedance in HFSS or if this method is right  is there any one who  validate it by the measurement?
Thank you,
I'm glad to see the question, because I meet the same problem. I want to know how you set the excitations and wether use the lumped port.
Question
While performing measurements , using a solartron based Impedance analyzer (with range 36 micro Hz-36 MHz), i am facing the same repetitive pattern of noise/oscillations during frequency sweep from 1 MHz to 0.1 Hz, even at 0V DC.
Noises are being observed in specially 3 regions of frequency, as shown in attached figure.
1) First one is above 1 MHz
2) At or just below 100KHz
3) Below 100Hz (Exactly at 50MHz) & heavily random noises towards 1 Hz.
The above 3 Noise /oscillations are dominating/ growing with increasing Dc voltage.
At 50Hz (as shown in 2nd figure) , it is expected to be the interference of outside Ac noise of 50 Hz( as we are not using Faraday cage) but what about the other frequency ranges ? Is it due to the aforesaid reason and will be solved by using metal faraday cage during impedance measurement or anything else are the culprits?
Here,for reference, i am attaching 2 figures of measurements, Please let me know the possible reason and their remedies for smooth Impedance data.
Ideal arrangement, use as much averaging or integration as possible. Operate the DUT on battery if an active device. If you are not in a screen room or a Faraday cage, making noise measurements is tough at best! That said, you can make a Faraday cage large enough to house the DUT and the measurement instrument using copper screen and a wooden box frame. Try running the test instrument on an isolation transformer. If you suspect low frequency noise degradation is a bigger issue, try obtaining mu metal as used in shielding CRT's. Make a mu metal shield for the DUT. Even steel chassis with some iron alloy added will assist.
Question
When building a circuit using Impedance Model Editor in Gamry EchemAnalyst software I am getting the warning "One or more components has missing wires".The images with warnings are attached. Can anybody suggest the exact way to biuld a model circuit avoiding these warnings?
Hi Kaushik
You probably have the attachment of the wires of the highlighted component in reverse. I suggest deleting the wires and reattaching
Question
I get the impedance values (real and imaginary parts) from the EIS technique. Can we correlate to it any dielectric property (dielectric loss, dielectric strength, or dielectric constant) using an equation, etc?
I do not have an exact answer. Maybe this reference can help it is a Maple worksheet if you have Maple software. https://www.maplesoft.com/applications/view.aspx?SID=154540
Question
I am testing the impedance of a material that will be used for ECoG electrodes.
I was told to test it at a frequency range from 1 Hz - 100 kHz but why is this range used? I wasnt able to find a satisfactory answer.
Which impedance values are good for recording and why? Is there a range ?
Kind regards
Lester Viray can you help him professor
Question
Can anybody tell me about the theory for the ionic conductivity measurement with AC impedance analysis using Arrhenius and VFT plots?
Dear @Puhup
Since electrical conductivity is the reversal of the resistivity , so you can conduct EIS measurement and then in Nyquist plot, the intersect of the plot with the real axis is the solution resistance and its inverse is equall to the conductivity.
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Our lab has developed lower limb exoskeletons for gait training and rehabilitation.
The exoskeleton implements low and high impdenace through force-sensor based impedance control.
In this case, the user's dynamics such as weight, muscular force, joint impedance are considered as a disturbance.
I want to operate the impedance of the whole dynamic model, including robot as well as human.
For example, the robot user can feel his leg as a baby's leg under the low impedance mode.
If anyone knows how to implement this condition by using the exoskeleton, please attach any articles in the comments.
Thanks.
This is not what you want, however you can read this article and gain some knowledge. Our project's end goal is same.
Question
Hi guys
anybody can suggest an equivalent circuit for this impedance data? i tried so many models based on the may occur in my system but not fitted. my problem is with the loop in the low frequency. anyone can explain the probably meaning?
my WE is an copper mate wich i guess a barrier layer formed in the surface and its proof by XPS analysis, but my model not fitting.
i attached the files
thanks.
Before you start analysing the EIS data you should check that data are correct. This is done performing Kramersd-Kronig transform. In your case a si mple test shows that the data are incorrect.
Question
Dear friends,
I need equivalent circuit to fit in the electrochemical impedance data?
I have separate Equivalent circuit diagram for screen printed carbon electrode and polypyrrole on stainless steel. Kindly refer  the attached file.
With thanks and regards,
Eswaramoorthy K V
prof V.S Muralidharan Sir i want to know the procedure of ink preparation from PANI and polypyrrole?
Question
We checked the impedance of the SCE reference and found that is was about 500 ohms when placed directly in the cell and about 5,000 ohms when using the Luggin Bridge.
By adding more NaCl to the solution in the Luggin we reduced this to about 4000 Ohms
We replaced the frit on the Luggin, but no difference.
are these impedance measurements normal/acceptable?
thanks
Dear Dr. Martin Burke,
It's very important for optimum potentiostat performance that the impedance of the Reference Electrode in your cell is low! A high impedance Reference Electrode will cause problems that range from simple overloads to potentiostat oscillation. When in doubt...check your Reference Electrode.
The impedance of your Reference Electrode should be less than 1 kohm. An impedance higher than 1 kohm is not good and an impedance higher than 5 kohm is unacceptable and must be corrected. With a Gamry Reference Electrode, the problem is easily corrected by changing the Porous Glass Frit.
You can find a “Testing Procedure” at:
A reference electrode with a gas bubble interrupting its electrolyte path has a very high impedance. The bubble can be produced by electrolysis, from deaeration gas, outgassing of a heated electrolyte, or from trapped air. You should always check that your electrochemical setup has an unbroken electrolyte path from the working electrode to the sensing element within the reference electrode.
Be especially careful if you reference electrode has a flat isolation frit. If this flat surface is horizontal within the cell, it can easily trap a gas bubble. A 45 degree angle on this surface allows natural convection to remove any bubble that tries to stick on this surface.
Luggin capillaries are also notorious for problems with bubble entrapment.
For more details, please the source of these info at: https://www.gamry.com/application-notes/instrumentation/reference-electrodes/
Best regards, Pierluigi Traverso
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Dear colleagues, I have some EIS spectra to interpret that are not trivial. Do you recommend any review article or book chapter about EIS spectra of gels over electrodes? Thank you in davance
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Can anyone suggest me an equivalent circuit for (CdS thin film/Na2S2O3/Pt) photoelectrochemical cell? CdS thin film is deposited on FTO glass and used as the working electrode. Pt electrode was used as the counter electrode and Ag/AgCl as a reference. Observed Nyquist plot and Bode plot are attached herewith. I have simulated some equivalent circuits such as [R(RC)], [R(RQ)], etc. But the right side bend of the phase curve in the bode diagram didn't match with any of I tried.
Thank you.
the very simple R(RC) ECM (equivalent circuit model) is valid (only) at the (far) forward bias regime, both under:
1)dark [R(RC)]dark, as well as under varying
2)illumination(s) [R(RC)]L_Fluxes
conditions.
In reverse bias (regime), (ECM) things are more rich (and complex); but things seem to be much more interesting, as a materials' (and device's parameters) science tool.
So, in reverse bias, try the, quite good, ECM "R(R1Q1)(R2Q2)", both under dark and under illumination(s).
1. Avoid heating (by cooling the substrate, ...) under very high illumination fluxes.
Question
Hallo
I know the Fresnal equation but how they have added relative permeability in equation 1 and relative permittivity in equation 2 and then how we got sqrt of relative permittivity in equation 3.
I have attached reference paper also from which this derivation has been taken.
Fresnel equations
Question
I am going to build an energy harvesting circuit, which includes several diodes.
Diodes are non-linear components, whose impedance varies for different input voltage. This means that even for a given level of input power (AC input), the impedance varies all the time.
How can I determine the parameters of the impedance matching network in ADS to fulfill maximum power transfer from an antenna to a non-linear circuit under a given level of AC input power?
How can I check whether the impedance matching network for non-linear circuits is well designed (by using a vector network analyzer or some other methods) in practice?
Please kindly give me some instructions if you know any answer about either of the two questions.
There are some good designs of rf wireless power harvester in the literature. One may use a series resonance circuit between a low impedance antenna and the rectifier circuit. The series resonance circuit is composed of RLC wich is made to resonate at the rf frequency. The resistor is used to adjust the quality factor of voltage boosting series resonance circuit.Since the voltage is boosted then the rectifiers which are normally Schottky rectifiers will show low resistance compared to the impedance of the clamping capacitors in the ladder boosting network. Therefore the diode can be considered with linear I-V characteristics.
Best wishes
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Hello, I am actually working on corrosion in reinforced concrete but I have bad results applying EIS technique. The problem is that in high frequency range I can not get positive values in Z", additionally theta values show negative results and I have read some publications that this is typical of inductive materials.
The problem is that I have run some test without apparent problem but the most of of times I have the above mentioned problem and I think that problem is in connection but I don´t know how to correct this issue
The test is run with a Cu/CUSO4 RE, an inoxidable steel plate as CE and the WE is a corrugated carbon steel bar.
Edgar Ulises De Los Santos Preferible medir desde 10KHz en una década a alta frecuencia no se pierde mucha información, pues solo verías la resistencia en serie ;)
Question
Hello,
Can someone please help me to understand the concept of Impedance matching in Metamaterial Absorber. I have attached a picture. In the picture at 2.06 GHz, there is peak for Real (z) at and for img(z) is in negative so how its impedance of Metamaterial absorber matching with free space impedance.?
Question
I want to found out that is an equivalent circuit has associated with its corresponding impedance spectrum?
Conditions: 3E system in KOH 6M solution at the potential range of 0.1 to 100000 Hz and in open-circuit potential (Eocp=0.3 V).
I appreciate your taking the time to respond to me.
Question
Firstly, thank you for being interested in my question and opening this.
I'm having a hard time calculating input impedance by transmission line theory.
I'm a student studying microwave absorbers. In this field, it is necessary to calculate input impedance to finally obtain reflection loss.
I've uploaded a file showing the equation of transmission line theory.
In the equation, I wonder how I can treat 'j' in tanh when I calculate it in excel program.
I've tried solving the tanh part in many ways like this, but I couldn't
TANH((COMPLEX(0,1))*(2*3.14*((10)^(-2))*(2/3)*((M2*N2)^(1/2))))
TANH((COMPLEX((2*3.14*((10)^(-2))*(2/3)*((N2*O2)^(1/2))),1)))
IMPRODUCT("0+1i", "(2*3.14*((10)^(-2))*(2/3)*((M2*N2)^(1/2)))+0i")
I have no idea how I should threat 'j' in tanh
I'd appreciate it if you'd help me to solve this question.
Best regards.
Why don't you try the same using FORTRAN/C/C++/MATLAB etc numerical software. Excel is good for office work, not for research.
Question
Dear researchers,
In my bachelor thesis I'm currently performing EIS measurements on sulphated Zirconia using the Autolab PGSTAT302N and Nova 1.10 software. The SZ is measured in form of a pellet of 13mm diameter and 0,5mm thickness. With every pellet sample I'm experiencing noise specifically between 1Hz and 100Hz (see the pictures below). The SZ is loaded with Isopropanol by staying under an isopropanol-containing atmosphere for a specific number of hours. The pellets are then prepared with 10mg of conducting silver-paste on each side. With other samples (textiles) the impedance spectra look fine.
What could be the reason for this and what could I do to solve it?
Hello
This shape could come from non-sufficient conductive contacts (just supposing). You could try another type of conductive paste (like gold).
Regards
Loraine
Question
Dears,
I have gotten results from CST software and need to polt it.
One of the results is Impedance, and I need to polt it as a smith chart.
Is there a software plotter support that?
Sincerely,
--
Hayder S. Ahmed
Question
I want to simulate a coaxial cable in FEKO software. However, the results do not agree with the transmission line solution that uses the transfer impedance (Schelkunoff model). I m thinking that the terminations in the MoM (FEKO) simulation affects the inner circuit. any suggestions.
Also, how can I extract the transfer impedance of a coaxial cable from the MoM results?
check my termination in the attached image.
Yes, now I saw your figure. That's right . See details about "pigtail" on shielded wires: Pigtails effect on shielded wire coupling, Clayton R. Paul
1979 IEEE International Symposium on Electromagnetic Compatibility
Year: 1979 | Conference Document | Company: IEEE
Question
I use the Johnson-Champoux-Allard (JCA) model to predict a sound absorption coefficient of a rigid material. I've seen a lot of articles where this procedure is done, all the formulas are provided. Unfortunately, what I get is, for example, α = 1.5281 + 0.2485j (at 1500Hz) while it should be a real number 0 < α < 1 instead. I understand that the real part of impedance represents acoustic resistance and the imaginary part - acoustic reactance. But how do I combine these to achieve an absorption coefficient?
Yes, it works now! Thank you so much!
Question
Hello,
My name is Colleen O'Brien, a senior biomedical engineering student.For my senior project I am required to build a model of human abdomen to validate a device we are developing. I still am trying to find synthetic materials with acoustic impedance of 1.69 and 1.53. If you have any advice or recommendation it would be greatly appreciated. Thank you for your time.
Ballistic jellies, as used in firearms testing? Also I believe crash test dummies are made with a jelly material that approximates to “people”.....
Question
Hi,
Currently, I'm looking for a simulation of the sound absorption coefficient of a micro-perforated panel by using Impedance Tube in Simcenter 3D Acoustic. Is there any tutorial available for Sound Absorption Coefficient? Because mostly I found is for Sound Transmission Loss.
After the simulation, my target is to plot the acoustic impedance value (real & imaginary) vs frequency range. Is it possible? Is there anyone who has done this before. Any help would be much appreciated.
Thank you.
Regards,
Nur Arafah
Dear Jafar Nur Arafah ,
Unfortunately I'm not expert in Simcenter 3D. Anyway at the following link there is a user's manual and sections: 3-18, 3-23, 5-15, 6-2 may help you in your task.
Moreover notice that an alternative to achieve your goal could be to directly measure it on a sample. A scaled acoustical characterization of the material/panel is not so expensive and usually is affordable with a source (e.g. a loudspeaker), a microphone and a common personal PC with a suitable software. Few precautions should taken into account (such as that frequencies should be scaled up of the same scaling factor of dimensions, and few other things e.g. air/medium acoustical absorption at scaled frequencies), but it is not difficult to consider these effects (also in post-processing).
Absorption coefficient should be measured in accordance with ISO 10534-2 or ISO354 standards (you can easily find them on the web), scattering coefficient can also be measured in accordance with ISO 17497-1. From conventional IR measurements you can get almost all information you need.
Finally you may also think to have a first order estimation of it by proceeding in an analytical approximated calculation of acoustical velocity into the panel (averaged since the panel is micro-perforated - considering the percentage of total volume that is filled of air). Then Z could be evaluated starting from pressure level information (by simulation) and of course from the panel area.
I hope it helps, best of luck!
Question
For comparison of Impedance of electro-catalysts, we should give same potential value for all ?or we should give OCP?(which is different for each)?
The "same potential values for all" is the worst option. See this discussion:
Question
Hello,
I am researching an antenna designed to cover the whole W-Band (75-110 GHz) I found in this forum that when we put discrete port with 50 Ohm Impedance, the resulting Z matrix represents the antenna's input impedance. I attached the Z matrix result that I got from CST below.
My question is, since I can only feed my antenna with one line impedance value, how do I determine that value? And since the feeding line will probably have only real value, what should I do with the imaginary part of the antenna's impedance?
In this case I tried averaging the real impedance values from 75-110 GHz and it comes out as 175 Ohm. The antenna showed good return loss when I feed it with 175 Ohm discrete port. Is it a correct way to determine it? Or there is other formula I need to incorporate the imaginary part?
The solution you have tried is not a bad one. The reactive impedance is small compared to the resistive impedance, so doesn't affect the match much. If you want to make it better you may be able to tune it out with reactive stubs, which are short open-circuit or short-circuit transmission line sections in series or parallel with the feed line, which are the microwave equivalent of capacitors and inductors.
Mattaei Young and Jones can be downloaded free as a pdf from the internet.
I think the best real impedance to use is the geometrical mean, not the arithmetic mean, but in your case there is not much difference.
The reflection from your antenna will be better than -10 dB, maybe -14 dB, either of which is what some antennas aim at, meaning that less than 10% or less than 4% of the power is wasted, respectively.
Question
I used an Electrochemical Analyzer Model CHI604E, Made in USA to make this plot and I am not getting the supposed semi-circle plot. Please I need assistance. I used AC Impedance, AC Impedance-Time and AC Impedance-Potential, and all were irregular shapes.
Please someone should reveiw and advise. Attached is one of the plotted graphs.
Regards.
From the attached screenshot of your measurement, I think you are having a current overload scenario. Hence the constant current readings over such a wide range of potentials in both the anodic and cathodic directions
Increase the current range of your Potentiostat/Galvanostat.
If this persist you might wish to check your counter and reference electrodes.
Question
I am having difficulties in designing stripline on cst. The reference impedance should be 50 ohms and it should be straight line at 50 ohms. Please guide what mistake I am making. I played with the width of the stripline, the impedance varies but it not straight line. Why it looks like a curve?
A classical misunderstanding in this context: are you talking about a stripline or a microstrip? there is often confusion..(a microstrip is "open" ) For a microstrip as relevant parameters (char. impedance ; propagation constant) are frequency dependent since there we don't have a true TEM wave
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