Questions related to Electrical & Electronics Engineering
Hallo every one,
I did nanoidentation experiment :
1 photoresist with 3 different layer thicknesses.
My results show that the photoresist is harder when it has thicker layer..
I can't find the reason in the literature.
Can any one please explaine me why is it like that??
is there any literature for this?
Thermal management of electronics/PCB boards purely depends on the power it dissipates (component power dissipations). But the power dissipation values provided by the component suppliers are the maximum power dissipation and in realty on field the power dissipation is far from this max values. So, i am looking into other possible ways to determine this values, through physic or analytically maybe.
Any bit of information would be highly helpful !
Thanking in advance !!!
I will really appreciate it if somebody could share the software. My lab owns the stimulator but when we acquired it we didn't get the software nor the drivers. Grass doesn't exist anymore and "Natus" which is the company that bought it told me that "S88X" is a discontinued product and they do not longer provide support for it.
Its crucial for us to control the device from a PC.
Thanks in advance
I am delivering power to my device using a VNA with frequency ranging from 300kHz to 8GHz. I am trying to figure out the current that passes through my sample, or DUT. I can set the output power of the VVNA and measure the S11. Here is my approach.
Since the total current (the sum of the incident and reflected waves) at the DUT can be expressed as:
then, use P0=I*V0, so current becomes
I=sqrt(P0*(1-Gamma)/Z0), where Gamma=10^(S11/20)
Is this approach current? Another method that I thought of is to first measure the DC resistance, R. Then, the current can be derived as:
Is any of these correct? Any help is much appreciated.
In a hypothetical situation where I have two wires, ones cross section is a cylinder, and the others a star. Both have the same cross section area, both have the same length. What are the differences in electrical properties ?
Are there any experiments done looking into this ?
Also what would happen if a wire had a conical shape, by length ?
I want to simulate a circuit having pin diode to verify switching function of PIN Diode in x-band. What are the softwares that i can use..?
It is a network of 30 earth pits. 3 sets of10 pits.
I have disconnected all the 3 sets. However, when I check for the resistance between the network of first 10 and that of the second set, I get 45ohms. Should it not show in k or M ohms as they are not galvanically coupled. One thing is for sure that they are not shorted as the resistance is as high as 40+
If I disconnected one pit from the remaining 9 in the first set, I get around 250ohms with multimeter.
I am trying to decouple all the 3 sets from each other but to no avail.
is it due to the high conductive compound that has gone into these pits?
Meanwhile, I'll try to explore more on this
Out of these 5 universities can you rate them from top to bottom which is best for coursework and research opportunities for Masters in Antenna Specialization.
Arizona State University, North Carolina State University, Virginia Tech, The Ohio State University, UT Dallas.
Stabilizing techniques for transistor amplifiers are well known, and as we know the frequency of operation we can make sure of stable operation in that band. However, in oscillators and specifically parallel oscillators which oscillation frequency is wished to be defined by feedback loop length (phase delay) we end up with existing multiple oscillation modes. e.g. equivalent series feedback mode at low frequency.
my question is that in such oscillators how can we make sure of other modes suppression? of course we can check startup condition for modes, how ever this is an analysis technique not synthesis.
my intuition is that as oscillation starts from DC we should keep amplifier stable all the way to oscillation frequency. but I am not sure.
I appreciate it if you share your experience with others.
thanks a lot
I was working on a thesis project on a portable ECG device, I checked these
So it was basically biopotential->Amplifier->logging->displaying using Teensy(Programmable chip), Adafruit(Bluetooth Module), SPI LCD Screen, and resistors and capacitors.
I developed and assembled all except Teensy, adafruit, SPI LCD screen, as I don't have circuit on how to connect output to these 3 devices.
Can anyone share some other resources it would be very much valuable.
case1 : when Radio frequency wave transmision line is loaded with matched impendace, then entire signal is taken by load without any reflections..
case 2: when a Radio frequency wave transmision line is loaded with short circuit, then entire signal is reflected back...
Now what happens when both the above cases are combined?
where will the signal go and how much will be the reflection coefficient?
will the matched impedance load get any signal?
I am trying to design a PIN Diode switch for a WR90 Rectangular waveguide ( X - Band) using HFSS software. I have learnt from some discussion that PIN Diode can be modelled using sheets and boundaries but how exactly that model i can use inside a waveguide as a switch? what are the parameters or extra devices i need to add? I couldn't find any open publications on PIN Diode switch in x-band rectangular waveguide Can someone recommend me some books or publications or blogs for better understanding of PIN Diode simulation in HFSS inside a waveguide.
We have chips on which there is tin, which disappears after a while. Tin is used on the chips to glue the heatsink.
What is your solution for chips that have lost their tin?
Due to the lack of poor heat transfer, we can not use silicone paste.
I hope you are doing well.
Do you know, which camera is used recently for the GRENOUILLE technique in order to measure the pulse length of ultra-short pulses?
what features the camera should provide? Should it be fast or regular camera works as well?
This article names a camera but I am not sure it is used recently in experiments or it is out of date!
Attached is a document in this regard.
I appreciate your time and any feedback.
I have just designed a fuzzy system, and now I want to redesign it based on the fractional order. However, I have no idea where to start from and what to do. Could you please tell me what I should do and mention any related sources to study?
I would like to request your collaboration to take part in the survey, available at the links: (EN): https://lnkd.in/djVdWne (IT): https://lnkd.in/dnvK3eJ (PT-BR): https://lnkd.in/dVGWmHv This questionnaire is part of the project aiming to analyze the transition from a linear economy to a circular economy, comparing developed and developing countries, at a macro level (nations, regions, cities). The project is a partnership between the University of Brasilia (Brazil), coordinated by Professor Patricia Guarnieri and the University of Bologna (Italy), coordinated by Professor Augusto Bianchini.
Your participation is very important to us. Please share with your network! Sincerely,
From Few Discussion i got to know about PIN Diode Equivalent RLC circuit. Then in hfss created 2 cylinder blocks both in contact to each other, then for one cylinder i gave inductance and for other i gave resistance and capacitance for Diode off condition. Similarly for DIode ON condition, for one cylinder i gave inductance and for other resistance. But it is not working as expected. Please need some help to design it.
I'm trying to simulate VFTOs in EMTP, I came across an article which depicted the EMTP model for a 245Kv GIS. Unfortunately, I'm new to EMTP environment and I'm not quite familiar with it's library. There are some elements in the figure that I don't know. I would really appreciate it If you could help we with them.
I marked the elements in the attached pictures.
I am trying to solve the differential equation. I was able to solve it when the function P is constant and independent of r and z. But I am not able to solve it further when P is a function of r and z or function of r only (IMAGE 1).
Any general solution for IMAGE 2?
Kindly help me with this. Thanks
Is it possible to replace a flyback transformer with a common transformer in a high voltage power supply by modifying the circuit? and if yes, what kind of modifications are needed?
I ask this because making a flyback is harder than making a common transformer.
I have updated my manuscript but its the third time the reviewer send me this comment again.
What are the probable redox reaction during cyclic voltammetry?
Could anyone guide me on this, please
Thanks, A lot in advance for your precious time.
If you refer to the images attached of opamp, one is open loop config of opamp and the other is the closed loop config of opamp. In both of these equations, the formula to obtain output voltage remains the same including the common mode signal affects. However, the Adm term, called as the differential gain of opamp or the circuit, in open loop config refers to the open loop gain of opamp while the Adm term in the second circuit refers to the closed loop gain of opamp. The books I have referred are: Microelectronic Circuits (Seventh Edition) by Sedra Smith, and Op-Amps and Linear Integrated Circuits (Fourth Edition) by Ramakant A. Gayakwad.
Is the reason because the Adm and the Acm in the first circuit refer to the differential gain and the common mode gain of the circuit and the circuit is opamp itself so Adm and Acm are the differential gain and the common mode gain of the opamp itself? While in the second circuit, the Adm and the Acm are the differential mode gain and the common mode gain of the whole circuit? But I saw in Sedma Smith that for the second circuit, output voltage formula of opamp being used in terms of open loop gain without including the affect of internal common mode gain of opamp.
I have been studying quantization in context of Digital Image Processing. I referred to the 4th edition of the book titled "Digital Image Processing" by Rafael C. Gonzalez and Richard E. Woods.
In the book, the intensity quantization levels are defined as
where k is an integer.
Now the first thing that comes to my find is why is that the quantization levels should be integer multiple of two and why not just any integer in general.
A paragraph has been attached regarding this from the book.
Then I found a homework problem and its solution online which are both attached as images.
In the homework question, I believe n is used in place of k to calculate bits per pixel or bits per picture elements. While k was defined as integer in Gonzalez, here n comes out to be 3.32 bits per pixel (not an integer). Isn't it a contradiction?
I want to make a decision making device by nearby active bluetooth devices using HC-05 bluetooth module with arduino nano but I stucked at programming algorithm to find active devices.
It is similar as arogya setu app's concept.
Kindly give your attention on this question and provide me its resolution.
Dear Researchers :
If someone is proficient in COMSOL and knows about the physics and applications of Electric Power Cables
Can help me on solving this model? What am I doing wrong ?
I need to compute the Temperature Distribution of this 2D model of a MV (35 kV) Power Cable.
The configuration is simple, and the application if for 25 kV AC.
I used a Study in two Steps
Step 1: a Frecuency Domain Analysis to solve first the Electric Currents (ec) and the Magnetic Fields (mf) physics. Followed from a
Step 2: a Stationary Study to solve the Heat Transfer phenomenon and its coupling with the (ec).
I'm attaching this image to shown how I can't get a Temperature Gradient, the Gradient I am getting is so tiny that practically the Temperature is uniform across all the Cable.
I'm doing something wrong
I'll appreciate the help,
Best Regards !
We know wind turbines extract energy from the wind in order to produce electricity, the wind downstream of a turbine has a lower energy content than the wind upstream. Suppose, the understudy region is formed of two zones (Figure attached). In the dark red zone, the initial wind velocity is greater than that in the light red zone.
Bearing in mind the different initial wind velocities, How to determine the resulting wind speed, due to the wake effect of turbine 1 on turbine 2 (case 1) and of turbine 3 on turbine 4 (case 2)?
Scenario: The problem in case 2, perhaps the recovered wind speed at turbine 4 is greater than V0 =8 m/s (initial speed at light red region)
how can i plot the same figure ( desired figure ) for Required leakage inductance with respect to operating power rating and phase shift for DAB converter i tried so many times i think i have problem with my Matlab code , can anyone help me with it ,
I'm sharing my MATLAB code and ( desired figure )
Kindly suggest which routing algorithm is better to implement for finding the optimal route in wireless adhoc networks?
Performance criteria :end to end delay , packet delivery ratio, throughput
Journals with review time of 2-4 weeks and publication time of <6 months.Impact factor journals >1.
IS there any literature that analyze selection of window length of window in rooling/moving RMS of voltage signal?
I log data from oscilloscope, and then I calculate RMS voltage, but I am not sure the length of the window? Are there any rules about this?
As you know, non-technical energy loss is a major problem in distribution networks especially in traditional ones with no smart meters. I know that the huge amount of non-technical energy loss is caused by electricity thefts mostly in rural areas. Nowadays, the novel configurations of networks are prevailing which can prevent at least electricity theft. However, it is still happening and results in huge amount of money loss! Here are my questions:
1. What are the other causes of non-technical loss and how can we reduce them?
2. Who must pay for it?
3. How can we consider it in novel electricity market places?
4. What is the easiest way to detect and prevent/reduce this type of loss in networks?
Any ideas would be appreciated.
Thank you in advance.
Are there any models to predict when an "Electrical Tree" or a "Water Tree" will occur inside an electrical insulator (dielectric materials as Polyethylene, Polypropylene, etc.) working on its normal operating conditions for Medium Voltage or High Voltage applications ? i.e. the Electric Insulator material covering the conductor cable in underground power cables (MV and HV)
Are there any theoretical or empirical models to predict these phenomena ? When treeing will occur along the life of an electrical power cable?
Hello Dear colleagues
in the figure below there are two relaxation oscillator circuits they do the some function that generate triangular and signals. However, what are the technical difference between these circuits? and in particular when i use the circuit in figure (a) and when i use circuits in figure (b)?
When it comes to choosing a good journal, it has always been debated which one is more important? Impact factor (IF) or journal quartile (Q)?
I give an example, you have three following journals, which one would you choose?
1- IF: 1.3 & Q1
2- IF: 2.5 & Q2
3- IF: 3.9 & Q3
Please select one of the three journals above and give a reason for that.
Is XLPE best insulator material for Medium Voltage underground electrical cables for Transmission Lines?
Normally the rated operation temperature for XLPE at this applicaction is 90 °C, So the temperature is not an issue , but what about the weight, cost and amount of material required for one meter of insulated Aluminum/Copper
Best Regards !:)
I am trying to simulate the following case: A three-phase source in a Matlab is connected to a Vienna Rectifier which is supposed to supply power to a resistive load of 50KW. Output DC voltage to be 800V DC and the input voltage is 400V AC. Technically a Vienna rectifier after rectification also improves power factor, that is, reduces the input current distortion to be less than 5%. I have designed almost everything correctly still neither the Vienna rectifier is reducing the input current distortion nor it is boosting the output voltage at the DC link to be 800V. I cannot figure out what is wrong. I am trying to solve this problem for the past 2 weeks still no solution.
To run the simulation, first, run the Vienna_rectifier_data.m file and then simulate the test.slx
The Matlab version is 2020b. If you need me to convert to an older version I can do that too.
Any kind of help is highly appreciated.
"Self-fulfilling prophecy" is Moore's own definition, while "a convenient fiction" is somebody else's...
I have decided that, giving some excerpts from two relevant articles will be more helpful than trying to explain my personal views in detail.
Excerpts from the article "Was Moore’s Law Inevitable?" by Kevin Kelly:
(...) Writing in 2005, (...) Moore says, “Moore’s Law is really about economics.” [Moore's colleague] Carver Mead made it clearer yet: Moore’s Law, he says, “is really about people’s belief system, it’s not a law of physics, it’s about human belief, and when people believe in something, they’ll put energy behind it to make it come to pass.”
(...) Finally, in a another reference, Mead adds : “Permission to believe that [the Law] will keep going,” is what keeps the Law going. Moore agrees in a 1996 article: “More than anything, once something like this gets established, it becomes more or less a self-fulfilling prophecy. The Semiconductor Industry Association puts out a technology road map, which continues this [generational improvement] every three years. Everyone in the industry recognizes that if you don’t stay on essentially that curve they will fall behind. So it sort of drives itself.”
(...) Andrew Odlyzko from AT&T Bell Laboratories concurs: “Management is *not* telling a researcher, ‘You are the best we could find, here are the tools, please go off and find something that will let us leapfrog the competition.’ Instead, the attitude is, ‘Either you and your 999 colleagues double the performance of our microprocessors in the next 18 months, to keep up with the competition, or you are fired.'”
Excerpts from the article "A Moore’s Law Mystery" by Rose Eveleth:
(...) Moore’s Law probably didn’t start as a marketing ploy. Even Carlson will admit that. But it then became, what he called, “a convenient fiction.”
Thomas Haigh, a historian of technology at the University of Wisconsin, had a similar idea. “[Moore’s Law] has always been more of a self-promotion for the wondrous accomplishments of the semiconductor industry than a law of nature,” (...) “It’s also been a kind of self-fulfilling prophecy, since it’s taken ever larger investments of research and development money to keep it coming true."
I am currently working on a soft strain sensor having a wavy fluidic cyclic channel. To get data in the form of electrical, I have to attach electrodes to both ends of the fluidic channel of the soft strain sensor and it must be properly attached so that fluid in the channel may not come out of the channel. But I am confused, which electrodes should I use for this sensor?
Hello to all Researchers :
I'm looking for someone, or some Article, where I can find numerical simulations of Electrical Trees in dielectric materials like Polypropylene, Polyethylene, PMMA, XLPE, etc.
Does someone have some information about this topic and these kind of works ?
Regards ! :)
in an islanded microgrid to control voltage and frequency, we need control methods such as droop control.In general, selection of the power
sharing coefficients and controller parameters carefully will promote the system performance against disturbances and load changes. in the sys with multiple DGs using trial and error methods to select voltage and current PI controller parameters consume time. Is there a step by step way to do it?
I could not get desirable results using given parameters in special paper.
I aim to analyse the permeability of aluminum to liquid gallium by measuring it's velocity at individual grain boundaries using ultrasounds.An ultrasound-based characterization technique is motivated by its higher temporal resolution.
But open to more suggestions regarding the problem statement.
When I was an engineering student, while investigating a circuit schematic, I was often discouraged by a device whose symbol I was not familiar with. Thinking that it was a different device, I was usually giving up. In some of the cases, I was finding out (much later) that the device was actually just a regular device (e.g. an inductor or a Zener diode, etc.) with another symbol accepted/used by some other engineers.
When I started to teach electronics, I noticed that I should make convincing explanations for my students to relax them about such occasions. For example, I mention multiple symbols used for Zener diodes, along with the meaning/purpose of essential items of each symbol version. Unfortunately, sometimes I cannot convince some of the students about this many versions of symbols used for the same specific device.
This issue can be an important problem when you are publishing or reading papers in different scientific journals.
Now, I remembered another case -although not very similar-, namely the unit of electrical conductance, which is given with the unit "Siemens", as well as with 1/Ohm, represented by Ω-1 or by ℧ and even by "mho" (Leaving away the "inverted omega" symbol which I also regard as unusual, I have always thought that, Georg Ohm would not be happy about the "mho" unit).
Of course, some symbol versions (e.g. some of the ground symbols given in the figure) may represent a slightly or substantially different property/behavior. However, many people occasionally use those different symbols to represent the same specific device. With no doubt, that's another aspect of the "multiple symbols" issue.
For sure there are multiple standards that we cannot alter to fix a unique symbol for a specific device.
On the other hand, this "multiple symbols" issue often creates problems, especially for the students who are in a struggle to learn/understand new devices.
The "handy" versions of the symbols (like the last ground symbols in the figure) preferred by some instructors may complicate the issue further.
A symbol which reminds of the device's main behavior, points out to difference and similarity with another device, provides ease of drawing and ease of spotting the device on a schematic, etc., can be assumed a good symbol (This can explain, for instance, the different versions of Zener diode symbols).
I know that many of you may think that I am exaggerating the problem. Nevertheless, I would like to know what others think about this issue.
Any personal experiences or suggestions which may be helpful especially for teaching will also be appreciated.
I am seeking on how to determine the sample size for pass-fail tests, and am unsure of the correct formula to use. I would like to use a 5% margin of error and be at least 90% confident from my sample size. I've read numerous articles that you must test 59 and all of them must pass the test. What happens in that strategy if one of the 59 doesn't pass? Do you need to test another 59? Any help or insight would be greatly appreciated.
Hi, a friend wants to publish an article related to the mobile robot navigation slam algorithm. Could someone please suggest a few journals with low impact factor?
I have dataset which shows the length of power lines. I need to classify the lines based on the line length. Is there a rule to classify the High voltage (HV) and low voltage (LV) lines based on line length? For instance, can we say lines below 500m (meters) are considered as LV lines and lines above this length are HV lines?
Is there any direct relation or equation between the open circuit voltage and the instantaneous voltage produced at the output of the PV panel at a particular irradiance and temperature value?
I am simulating helix antenna in hfss, right now, giving excitation with 50 ohms port. When I see the results of Z parameter (real). It shows lower than 50 ohms. Do not understand, if it can be true or I am making any mistake. Please advise.
Is there any article or project about interaction of the "Schumann Resonance" on the brain alpha or theta waves?
- The Schumann resonances (SR) are a set of spectrum peaks in the extremely low frequency portion of the Earth's electromagnetic field spectrum :: Schumann Resonance Freq. : 7.83 Hz
- Alpha waves are neural oscillations in the frequency range of 8–12 Hz
Impulse voltage= 1 volt with and 500ns domain
Will the structure change by injecting a small surge voltage into a solar panel? Will the values of the series and shunt resistance change?
So, I have a design, two dipoles working at UHF and VHF. We fed using a diplexer. I am having difficulties with the testing using network analyzer. VHF passes but UHF, specially at 400 MHZ, the VSWR shoots to 2. 1 or even 2.3.
Is there anything I am missing and replace to pass vswr for UHF too?
I would like conduct DMFC experiments. Which instrument or tester to be used for measuring 0-1000 mV voltages and 0-5000 mA current. The peak power generation by the cell is 0.5W. Is it possible to make my own set up for this experiments?
How can I know how much power an antenna can handle? I know P = I^2*R, but here I only know R = 50 ohms. how to determine, this antenna can handle this much power? I am working on dipole and helix antenna.
Thank you in advance.
So, I have a helix antenna designed for 400 to 900 MHz. This antenna is designed using fabric and as a fabric, it gets wavy and scrambled which changes the performance of the helix. I am thinking of sewing a stabilizer (a thick fabric), which embroiders use so that the fabric can be stabilized as much as possible. But, I need suggestions on this idea as I do not know if I am making antenna LOSSY after sewing a stabilizer behind the fabric. I am attaching the stabilizer picture
I’m using COMSOL for circuit breaker PSS-1 2D time-dependent simulation. I have coupled all moduls: Heat Transfer in Fluids, CFD-Modul, Electric Currents, Magnetic Fields, Moving Mesh
in HT-Modul I use 3 HeatSources for Simulation of radiation, Joule-Heat(ec volumetric los), enthalpy transport.
in CFD Modul I use Force for Lorenz-Force consideration
EC and MF moduls are coupled with external current density.
MF:full field, ”in plane“ field, gauge A-fixing
boundary conditions: walls
initial values: T=293K, P=1atm(with hydrostatic correction), DC terminal 100A and ground.
between electrodes T=10000K or I tryed to use Gauss-Pulse function (quasi same effect)
Solver: fully coupled
Method: High-nonlinear Newton
Goal: to simulate plasma in switching device correct and watch internal thermo-hydrodynamics and V-A characteristics of circuit breaker.
when I start to calculate my modell, I receive no convergence in both Stationary and Time-Dependent cases.
when somebody need a comsol-file, just ask it
While feeling the shared pain of costly and slow PCB Manufacturing process. Which also makes the hardware creativity and education much costly and slow. I was trying to figure out how can we decrease the cost of PCB manufacturing, get it made quickly and still maintain the level of quality we currently get. I came across the concept of using UV laser for Board cutting boards and drilling board plus using Masked SLA type of process for UV expose.
- To me, this seems like a revolutionary setup.
- You can make every board different, which makes enables mass customization
- Very less wear outs as there are no drill bits to die
- Automation can be a much higher decreasing need for costly labour and faster lead time
- Fewer machines and setup costs which makes the footprint of the plant smaller
- Above 2 points can make PCB Manufacturing feasible outside china as well
- Maybe we can mitigate the setup cost of PCB and bring down the cost of proto PCBs to the cost of PCB manufactured at scale
All these seem that for at least 2-layer rigid or flexible PCB, a lot of initial costs can be mitigated and prototype PCB manufacturing cost can be decreased.
So what am I missing? What are the technical or commercial challenges you see in making with this way of manufacturing a PCB?
Do you think that artificial intelligence will be implemented in the control systems of driving and orientation in the field in autonomous cars?
What are the effects of artificial intelligence implemented in the field of driving control systems and orientation in the field of autonomous cars?
Will autonomous cars be safe?
Will autonomous cars be mostly electric cars at the same time?
Please, answer, comments.
I invite you to the discussion.