Science topic

# Electric Impedance - Science topic

The resistance to the flow of either alternating or direct electrical current.

Questions related to Electric Impedance

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.How to pick ideal AC and DC voltage for EIS measurements while testing supercapacitor? I understand that AC causes the perturbation for which I will be recorded by the potentiostat, but wha about the significance of DC?

I am looking for the electrical resistivity of these polymers, does anyone know of any article that touches on this subject? Any help would be appreciated.

What will be the equivalent electrical circuit of the following set of multiplied and divided impedances:

Z

_{1}/ (Z_{2}x Z_{3})It is assumed that each of these impedances itself represents an element or electrical circuit.

Hello Everyone,

I am a hydrologist and want to model baseflow (i.e. surface-water groundwater interactions) via the development of a numerical groundwater model (GW model). One of the critical input parameters for the development of the GW model is the hydrogeology of the catchment in question.

Bore-well lithology datasets required for preparation of hydrogeology map or Fence Diagram is very limited (2 borewell logs only), Since, my study area lies in the headwater mountainous region. I am planning to do an electrical resistivity survey for mapping the hydro-geology of the basin in the catchment area of 102 Km2. I have a few questions, in planning Electrical survey in the basin-

1. What could be the optimum number of resistivity profiles required for appropriate representation of hydrogeology of the basin?

2. How to identify the most appropriate locations for Electrical resistivity profiling representative of the basin under consideration?

I request you all to give suggestions in this respect.

Thanking You.

Regards

Rajat

Can anyone suggest research where I can find thermoelectric properties of Chromal P (10% Nickel, 90% Chromium)?

Specifically I am looking for:

1. Thermal conductivity as a function of temperature

2. Electrical resistivity as a function of temperature

Temperature range of interest is 20C to 800 deg C (1100K)

I have an EIS spectrum as illustrated in the images and I am trying to fit it by Randles equivalent circuit. My fit is not perfect but the question is which value should I use to calculate the conductivity of my solid electrolyte in the image? Usually, I was extrapolating the linear part of the curve down to X axis and take the value as resistance to calculate ionic conductivity according to the formula:

1/q=(1/R)*(l/S)

I recently read in this website that diameter of the semicircle can also be used to determine the resistance to calculate ionic conductivity. However, in my case both values are significantly different from each other. Therefore, I am looking for a more solid approach. How can I calculate ionic conductivity of my sample according to output of the Zfit? The value in the red marking is Warburg factor. Should I somehow convert it to resistance?

My sample is a lithium containing amorphous silicate thin film.

Why the ohmic resistance value shown in the diagram is different from the value obtained by the equivalent circuit in the zView software? Is this difference related to the software settings?

R(diagram)=2.27

R(equivalent circuit)=2.109

Can this amount of difference be ignored?

Is there any way to get the exact values?

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?

Thank your reading

Metallic pipes are known to show low resistances compared to their surroundings(Vickery & Hobbs 2002). Does this imply we can effectively use ERT method to detect metallic pipes in the subsurface.

I'm having problem with the correct determination of Rct(Resistance to charge transfer) and your value for a Randles Circuit with Waburg impedance. I just find methods with extrapolations. Can I calculate with some mathematical method?

I have grown thin films (~100-500 nm) of PEDOT:PSS by electrodeposition on top of thin films of Au (~1 nm) and now I want to measure the impedance of the PEDOT:PSS thin film.

To accomplish this I am thinking of depositing another layer of Au (or another conducting metal) on top of the PEDOT:PSS for it to act as a capacitor and use 4 probe method to measure its impedance.

However I am apprehensive that by using a magnetron sputtering technique to deposit Au on top of the PEDOT:PSS thin film will alter its properties, rendering the impedance measurements not viable.

I can also do IBD deposition of Au, but I think this will be worse. I could also electrodeposit Au, however in doing that I needed to apply a negative potential which would reduce the deposited PEDOT:PSS rendering it non-conductive.

Opinions on how to deposit a conducting (can be very thin) layer on top of PEDOT:PSS without interfering with it ?

Thank you for your time.

I want to measure electrical resistivity of a silicate glass in the melt state. The temperature is between 1000-1500C and the accuracy is not so important (5% error is acceptable). I found out that two wire method is a good way for measuring but I did not find enough information about the method. I have some questions like what is the surface area in this method? (I mean A in the formula p=R.A/L) or can I use DC current for measuring? and etc. If anyone can help, it will be appreciated.

Dear Researchers,

Grid impedance measurements/estimation techniques have been used to find the value of resistance and reactance of a three phase line. I would like to know the technical reason,

**why the values of R and X of a three phase lines cannot be accurately measured through R=V^2/P and X=V^2/Q**considering the power factor unity just for simplicity. Technical reasons would be appreciated. Thank you.I made some impedance measurements under magnetic field to characterize magnetoelectric coupling on BTO-CFO composites. I can determine magnetoelectric coefficient by calculating dE/dH from obtained data.. i just don't know if such coefficient is enough reliable to report it in an article.

The theorem states that the reactance of a passive, lossless two-terminal (one-port) network always strictly monotonically increases with frequency. Can this theorem be extended to two port circuit parameters like mutual impedance etc.?

Let me first say that I am a beginner in electronics so I don't know about opamp.

I am using transimpedance amplifier for DISCLC measurement. The aim is to convert a small current signal into a measurable voltage signal to be read by an osciloscope without increasing the RC time constant of the device.

A device is connected to inverting terminal of an opamp, the non inverting terminal is grounded and a feedback resistor is connected between output and inverting input. A square wave is fed into the device from a function generator.

Since input impedance of opamp is very high (infinitely), the current through the device is equal to the current through the feedback resistor. The current does not flow into the opamp.

My question is, why does not the feedback resistor affect the RC time constant of the device since this is the only path for function generator circuit to be complete?

I want to know how does the suming point (inverting input) work exactly as the ground of function generator? How is the device charged to peak value of function generator skipping the Rf path?

Some people are using ohm.cm

^{2}and others are using ohm/cm^{2}as the unit of impedance in their publications for EIS analysis. What is right one to use ?thanks in advance

Dear all:

How I can calculate the Impedance of a single white colour LEDs Strip? Does anyone know ?

I have a Strip of white light LEDs , at a Voltaje imput of 12V .

I'll appreciate any help :)

Regards !

My department recently got a hold of an ECIS-Z machine for measuring cell monolayer impedance in real-time. I have been having issues getting the 96-well plate to properly align with the 96W array station. I always have between 2-6 wells fail the initial SETUP when the device is checking connectivity (occurs randomly). The department that loaned us the device did provide the 96-well plates and I noticed that they are 3 years old. My thinking is that the plates themselves are bad due to being so far out of date. I was wondering how difficult the procedure is with brand new plates when you initially insert them into the 96W array station. I have ordered some brand new plates so I hope I have better success once they arrive. Any advice or experience using the device is greatly appreciated.

For large area SOFC testing I am using Scribner's test station. For the cell test I am using Ni-mesh and Ni wire as voltage send and current collector which is connected with the manifold using Ni-paste. So I found a large ohmic resistance (70~80%) of the cell compared to the total resistance while the polarization resistance is only 20~30%. So I doubt whether the position of the voltage send dose affect for high contact resistance. Please find the figure for the setup.

I have a question about the precise calculation of carrier density by the use of mott-Schottky equation for nanostructured semiconductors. As one of the assumptions for Mott-Schottky equation is having a planar semiconductor, usually the calculated carrier density becomes too high for nanostructured photoanodes ( even higher than metals) used for photoelectrochemical water splitting. This is probably because the real surface area of the nanostructured is much larger than simply the geometrical surface area of adjacent semiconductor with electrolyte. Another point is that how can we consider a shape factor for capacitance in the mott-Schottky equation. I mean should we consider a shape factor when we have nanowire or nanoplate structure on the surface of a photoanode? Besides that, for this case is there any suggested method that can help us reach a close-to-reality calculation of carrier density in nanostructured photoanodes?

After changing a lithium ion (LFP) battery's SOC eg: 100 to 80 % and the cell is now made to rest to attain equilibrium. During this wait period, what all parameters change ? And it increases or decreases ?

So far, my finding were the charge transfer and double layer capacitance decreases during this wait time (through EIS spectra). Any other parameters change ? References will be useful.

Hi , I'm trying to measure impedance of my PBS solution at 700 kHz with 100 mVpp within my 80*40 um microfluidic channel .the flow rate is 50 ul/min. I don't know why my 40 um width electrodes detach while testing.. the thickness of chrome layer is 10 um-30 um and Au layer is around 100 um. Chrome Au annealing at 450 deg c for 13 mins used in order to promote adhesion for some samples but the problem still remains. What is your idea?! what shall I do !?

I have a GNSS RF chip. I should connect the RF pin to an antenna connector with a 50 ohm microstrip transmission line.

I calculated the RF track width and printed the PCB

Now I want to measure the track impedance to verify calculation and design.

Is there any measurement device for that?

*The frequency of RF signal is about 1.5GHz.

In analyzing the electrical performance of multifunctional EDLCs, our group is using cyclic voltammetry testing to determine capacitance and attempting to glean information about the electrochemical activity of our system. In commercial EDLCs, CV plots are rectangular (often considered "ideal capactive behavior") and show stability at high voltages. Some say high ESR will cause the top-left and bottom-right corners to round, while low leakage resistance may skew the graph shape vertically. However with our EDLCs, we observe the "ideal" rectangular shape at low voltages (Picture 1), but when pushed past a specific voltage, a tail-shape deviation is seen in the top-right corner of the plot (Picture 2). We suspect this "tail" is an indication that our electrolyte is unstable past a certain voltage. What is the significance of this "tail"?

I have simulated a simple rectangular loop (10 mm X 2mm) in both CST and HFSS from 1MHz to 2GHz. Then I extracted Inductance using expression L= XL/(2*pi*Freq). I noticed that the inductance remains fairly constant till 10 MHz, then decreases till 322 MHz and again starts increasing. (Please see attached file). How to explain this behavior?

Im doing a piezoelectric energy harvesters and intending to use a standard piezoelectric circuit with bridge rectifier and smoothing capacitor to charge a NI-MH battery, can it be done? I saw lots of article mentioned about impedance matching. Do i need to do a impedance matching with the piezo and the battery? how can this be done, by adding resistors?

Appreciate any kind of help. thank you!

Dear friends

I want to carry out impedance spectroscopy of my samples, if anybody knows the place for same kindly suggest me. Future, I want the data in term of Z' (real part of impedance) and Z'' (imaginary part of impedance) with frequency and temperature and the data file should be open and competible in Z-view software.

Please suggest me as soon as possible.

when we design any millimeter wave antenna for e.g at 1-2mm, what type of connectors are used?

The eq used is -

C

_{s}=(i)/(m.dv/dt)What is this "i'?

Hi all,

I have been trying to use the NI USB-6008 for voltage measurements. I observe that just by connecting the card to the circuit I am observing some signals that should not be present. Even grounding as mentioned on the National instruments website did not help. What might be the issue? I am measuring voltage drop across a circuit with impedance in the range of 150 Kilo Ohms. (Pure Resistor circuit)

Any help will be much appreciated.

Thank you very much!

What could be inferred from changes in the imaginary component of impedance over time when running electrochemical impedance spectroscopy (EIS)? Thanks

1N=kg*m/s² vs. resistivity, electic power (s³), capacitance, permitivity (s^4)...

plot against charge carrier density and the ratio of the Hall resistance (Rxx/Rxy) which is shown in the figure (attached below). any explanation and comments in your views will be highly appreciated

I have this new IVIUM Technologies Electrochemical Spectrometer and I´m trying to collect EIS data of a symmetrical ceramic cell from RT to 800 °C but all I get above 1 Hz is unreasonable impedance values (negative Z' and/or Z'' 2 o 3 orders of magnitude larger than the expected signal that should be a few ohms).

I am characterizing some metal-oxide for charge storage. I was interested in seeing the impedance spectroscopy of my material. The EIS was performed with a sine wave of 5mV amplitude from 1Mhz- 0.01Hz. In the EIS spectra, there seems to be a tail kind of structure in the high-frequency region, rather than a semi-circle. I'm suspecting that this is a potentiostat problem as I tried changing different variables like the amplitude and the scan range without any luck. I was wondering if some can help me solve this issue. Thanks

I have created a rectenna circuit.

I want to check the Input and output voltage to calculate effficiency

I have manufactured some capacitors with silica as dielectric and I have measured them with an impedance analyzer, the Nyquists I was able to model them with the radle circuit. By plotting the normalized active and reactive powers for the complex power as a function of the frequency I have observed that they intersect at one point, even at one of the capacitors it crosses at two points. I have read in supercapacitor studies that the crossing of normalized powers is attributed to dielectric relaxation, but I do not completely understand what it means and why this happens with my capacitors in which I do not use any electrolyte.

Hello,

I am running EIS to determine the impedance spectra of my sensor. The sensor consists of gold electrodes deposited on a porous paper membrane. And the electrodes are modifying with a thiol molecule.

I am then taking an EIS measurement in a phosphate buffered solution (attached), and would like to fit this data to an equivalent circuit. I have tried a simple RS circuit, I have tried a Randle's circuit, but the data does not fit very well.

I did some digging and found a paper (linked) with a circuit that fits my data well; however, I'm not sure I can use it to describe the processes that are occurring in MY system. Any advice on how to better fit my data?

Thanks,

Hunter

Hi, I wanna measure cell impedance. I've seen some equipment in the papers but I need a source that illustrated all detail of set-up.Could someone help me?

I appreciate any help that you will do

I am using four-probed method on Zive SP1 Potentiostat to obtain Nyquist plot for proton conductivity measurement of proton exchange membrane (SPEEK). However, I could not get a proper Nyquist plot shown in literature, instead my impedance value is very random when the frequency is decreasing from 0.1 MHz to 100 mHz. May I know what is the major problem?

When I manage to obtain a Nyquist plot, how can I fit into my equivalent circuit to obtain the bulk resistance?

Thank you

I want to calculate the current density across IDT electrode, both electrodes are on the same surface of a

**solid material (a bulk ceramic disc).**Imagine two parallel bar electrodes with length L, and separate with distance D. The material thickness is T. When a bias voltage, V, is applied between the electrodes, how to find the current density? How to find the effective area that current flows?

Many thanks!

Dear all,

I have observed an interesting phenomenon during my experiment.

A conductive wire was used to connect a power supply's GND with the ground. The resistance of the wire measured by a multimeter (Agilent U1213A ) is 0.1 ohm when only one end is connected, this is normal.

However,

*when the two ends are connected, the measured resistance of the wire is*. That's weird! I repeat the measurement again and again but doesn't change anything.**21.8 ohm**The wire is made of aluminum with diameter of about 2mm. The power supply is turned on during the measurement, and the voltage drop on the wire is 0.124V.

Could there be any explaination for it?

Dear friend; I have problem with Zview or other free software to fit equivalent circuit. Zview just pick up 15 point in my EIS text file. What should I do? I have tried other software such as Zsim or MEISP. All of them are Demo version and don't allow me to fit equivalent circuit on my data? Please suggest me a practical method. Thanks

I have measured I-V characteristics of the pellet which is made of the powder sample (which is n-type) and connecting with copper wires on the both sides of the pellet with the help of silver paste which is stuck on the surface of the sample, it appears in non-linear nature which I have attached here. According to literature survey, this is Schottky type nature. But I don’t know why this type of non-linear nature comes in this I-V characteristics which bend in some position and after that, it is likewise expanding. What could be the possible explanations?

Hello researchers please tell me regarding what the real impedance vs imaginary impedance nyquist plot of fet transistor tells.Actully I had plot the frequency analysis ( so called nyquist & bode plot) of a FET file attached but I am not able to understand that what it actually tells about my device.

Hi! I have experimental impedance spectra in format of .txt/.dat/.csv and I want to fit the specta and make an equivalent circuit by Zveiw. I've tried to open those .txt/.dat/.csv files in the Zveiw programme but data files opend incorrectly. Could anyone tell me how to solve this problem?

I conducted a complex electrical impedance measurement for a water partially saturated rock.My complex electrical impedance data (Z' and Z'') between 500 ~10000 Hz can be well fitted by a Debye circuit. Through the fitting, I obtained the resistance R1 ,R2 and capacitance C.

For example, R1= 112 ohm, R2=24 ohm, and C = 3.2e-6 F.

The capacitance is proportional to total permittivity (E) or dielectric constant (Er) according to this relation C = E* k = E0*Er*k

Here k is the geometrical factor equaling 0.03 m, E0 is the vacuum permeability (8.854e-12) and Er is the dielectric constant. Thus the dielectric constant D should be calculated as Er = C/E0/k. So I calculated the Er as 12047285. This value is very huge compared to the common literature values.

If I am wrong, could anyone help me to point out where did I go wrong?

Thank you very much.

How can I find the equivalent circuit of EIS spectra? I have run some Nyquist plots but I could not find the equivalent circuit or any given procedure for find out this circuit...so How we should find out this?

And does it change when considering the EDLC type or Pseudocapacitor type?

IF I want to match the impedance of Archimedean spiral antenna with the components like R, L, C. The impedance of antenna is 180 ohms with plus minus 20 ohms reactance. Please suggest and help

I am learning to calculate the maximum power of an energy harvester which is connected into a electrical circuit that consists of a resistance load. I always find the researchers measure the power output as a function of resistance. (ranging from kΩ to mΩ)

Can somebody explain the mechanism of this phenomenon, that specific resistance leads to maximum power, to me?

Follow by this question, if that specific resistance is found to be extremely high, i.e. 500kΩ, does it waste the energy generated by the harvester? like generating heat instead of being used for meaningful purpose?

I am trying to maximize the generated energy form a certain power source (Irregular one), so I want to reach the maximum power transfer via defining an optimal load impedance. It happens that the optimal Load is not pure resistance (as the source itself has some reluctance/capacitance), is there a certain Power Electronic circuit such as Boost Converter that can be designed to "Emulate" that optimal LOAD.

Thanks

Please refer to the picture attached alongside.

We use impedance network (DC side) in front of inverter and filters like [ L (or) LC (or) LCL ] after the inverter ( i.e AC side) which is connected to grid (or) local load. What is the difference between those two, in view of design and function?

I have already pelleted and sintered my cathode materials, and want to spread my solid electrolyte on it ,then measure impedance between them.

I tried to spread electrolyte on cathode pellet and pressed them into one pellet, but it always broke.

Another way is that I dissolved my electrolyte and some Naphthalene ,then loaded them on cathode pellet. But it seemed not work when I measured the impedance of the pellet.

My question is that if the ways I tried is not right ,or I need to modify something?

Thanks again‼!

Hello,

I want to find the junction thermal capacitance (J/K) based on the thermal impedance vs. time curve (we have this curve from the semiconductor specifications or IGBT module datasheet).

For instance, I attached a sample datasheet.

Thanks a lot,

I want to measure impedance between two bare gold electrodes in a PDMS micro-channel. The results (please see the figure) were scanned one after another with a time interval of few seconds. However, no matter what solution I use (PBS or KCl or other solution), the scanned impedance always decrease as shown in the figure. Does anyone know what is the reason? How I can get very stable results?

Not sure there are any practical advantages when you are pulsing a plasma just a few seconds, still there are proponents either way. I am interested in opinions from someone who has actually tried both methods

Hello,

I am trying to obtain the conductivity of a solid electrolyte by measuring EIS from a known area and thickness pellet.

I can not explain this weird values obtained on the impedance plots. Does anyone know what could it mean?

I would very much appreciate your help.

Thanks

How is Impedance Matching performed in Low Power and High Power Circuits?

In a four probe method, if the area between the two probes is constant, then will the resistance change with the sample size?

what is the reason of opposite y coordinate direction?

why +y direction is not important on impedance plotting?

In the derivation of Poole-Frenkel emission (Field assisted thermal emission), the trap barrier is lowered due to applied field and is given as

- Delta U = sqrt((e^3/ pi*\epsilon)*E)

where E is applied field.

The derivation starts from the expression of the electrostatic potential energy due to coulombic trap as

- V = e^2/(4*pi*epsilon*r)

From my understanding of electrostatics, the epsilon used in the potential energy expression is the low frequency permitivity (static permitivity).

But the confusing part is all the papers I have read so far say that the permitivity appearing in Poole-Frenkel coefficient is high frequency component( some say electronic contribution). How can the permitivity introduced in electrostatic potential energy become high frequency part when it goes to Poole-Frenkel?

Can anyone help me understand?

The importance of this is: plotting Poole Frenkel emission of leakage current, the dielectric constant (permitivity) can be approximated. What do you compare it with?

While studying piezoelectric transducer in frequency domain, it is found that electrical impedance has highest peak or value at fundamental frequency but decreases at higher harmonics. why it has a decreasing trend?

Specifically, how much blood volume is relocated to abdomen, upper leg, and lower leg when assuming a seated position?

In addition, what are the normal blood pressure and heart rate responses to passive sitting up from supine position?

I've run an electrochemical impendance spectra for my chitosan-Fe3O4 composite and compared it with Fe3O4. As expected the charge transfer resistance (Rct) increased (from 200 ohms to 600 ohms) due to the nonconductive chitosan film in the composite.

What I'm unsure is why the equivalent series resistance (ESR) is not increased in the sample but the it is the same and sometimes even slightly decreased for other samples.

I know that the ESR is attributed to the resistance of the electrolyte; the contact resistance between the electrolyte, current collector, and active material; and the intrinsic resistance of the active material itself.

So the increased Rct in the composite means the electron transfer is obstructed due to decreased conductivity in the composite but the unchanged/slight lowered ESR could mean that the intrinsic resistance (or other factors) of the composite remains unchanged. Is that even possible?

According to the impedance criterion of Middlebrook, the stabilty of a system is determinded to the ratio of output impedance and input impedance.

I have a question that the stabilty of a system is determinded to the ratio of output impedance to input impedance or input impedance to output impedance?

Does anyone have his thesis which is published in 1976.

I did scanning impedance experiment in wet-state and obtained a bode plot ( a graph of a frequency response of the gel). I want to separate Z' and Z" to draw a Nyquist plot.