# Questions tagged [electric-field]

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### Electrically long loop antenna with homogenous near B field inside antenna loop

I wanted to know is it possible to create a loop antenna that functions in a way like a high frequency helmholtz coil. Because a helmholtz coil is usually made with multiple turns of wire having high ...
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38 views

### Numerical calculation of the Electric field in a system knowing the potentials on the contour

I have a problem in numerically determining the electric field lines given the potential in a system described in the photo. The electric field vector E is related to the potential at a point with the ...
• 1,515
27 views

### Can a photon be modeled using AC driven electron and AC driven wire loop?

Can a photon ("electromagnetic wave packet") be simulated in software as an electron bouncing up and down (for the oscillating E field) and a loop of electrons with neutralized electrostatic ...
• 103
74 views

### Electromagnetics - Calculating electric field vector given an equipotential surface

I'm trying to figure out how to calculate the electric field vector given an equipotential surface with the equation $x^3 + y^2 +z = 1000$ where x, y, z are positive. The potential on the surface ...
• 701
36 views

### What differences in terms of fields does a grounded metal and an unconnected metal object have

I previously asked a question regarding absorption and reflections of waves to metal. But id like to know the differences that say a PCB metal pour that is connected to a signals return path, and a ...
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### Electric field in power transistors

I had a question about power transistors, why are small fields used in power transistors? I think this question could be because the voltage is high, but mostly in terms of the transistor structure I ...
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### How do I accurately recreate the ER effect (using electro-rheological fluid)?

I am working on a project that makes use of the unique properties of electro-rheological fluid (ERF), a substance that changes viscosity when an electric field is applied: For this project, I want to ...
• 101
59 views

### Effect of high voltage electric field on the motion of charged particles in an isolated tube

Please refer to the image for a visualization of the schematic. I feel I am trapped at this stage. I am trying to understand the following: In a closed container, charged particles are moving from the ...
98 views

### Measuring if a capacitor on mains is turned on by measuring radiated electrical fields far away

There is a house connected to German mains with hot, neutral and ground. Some distance away in the village there is a PWM source (most propably a solar inverter) which shows as 17kHz on the mains ...
• 123
105 views

### Why do we want detaching field lines in an antenna?

I have some questions about the link between the intuitive explanation for why an antenna radiates (based on this video) and the Maxwell equations. Q1. The video starts by saying that "an ...
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1 vote
178 views

### Why do the metal sticks (for the ground) on the ground plane antenna reflect and not absorb?

From my current knowledge, any metal whether grounded (and or earthed) or not will reflect radio waves as seen on dishes, Faraday cages, etc. On the other side the ground in transmission lines or the ...
• 647
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### "Toroidal transformer action in the presence of total B field confinement" (?!) Is Wikipedia wrong?

Wikipedia has an article about toroidal transformers and inductors. It is well known that an ideal toroidally wound coil has total magnetic field confinement due to symmetry in the case where the ...
• 25.3k
60 views

### How to determine the collector current limiting resistors for the Darlington's pair of transistors?

How were the resistors in the circuit calculated?, I would like to come up with a similar circuit but for a 5VDC power supply, and I would like to resize the resistors as per my load requirement, my ...
134 views

### How can I calculate the current induced in the copper coil that is wrapped around a single phase of an 11kV, 2616A distribution line?

Aim: To develop an alert system for power outages in the distribution line, informing electricians of their occurrence. Working Principal: Fuse Monitoring: The Arduino measures the status of the power ...
90 views

### Can a strong electrical field at power frequency (50 or 60 Hz) be dangerous to humans? [closed]

Usually, what is dangerous about electricity is the current – voltage is important as it will determine the current through a given impedance, but not "dangerous per se". So far, so clear. I ...
175 views

### Electric field of line charge and coaxial conductor

I'm currently having trouble understanding why the electric field inside a coaxial conductor (assuming that the charge is evenly distributed on the inner and outer conductor and opposite signed) is ...
• 91
178 views

### Estimate susceptibility of circuits to external electrical field strength

I will be soon testing a product to an electric field spectrum requirement (i.e. in the 100's of dBµV/m vs MHz), and it shouldn't be a problem because of how small the values are compared to the ...
• 9,896
73 views

### Help with circuit for school

I am doing a project for school with two friends. We are going to make a DIY metal detector. We are using a source as our circuit. Can someone help us describe what is happening in the circuit?
113 views

### Finding resistance between two conductors

For my electromagnetic-field class we are asked to calculate resistance between two electrodes shown as below. The part c(i) is just a simple resistance question using the formula R=pl/a. I don't ...
• 21
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### Is the field strength between 2 electrodes dependent in any way on the medium?

I want to apply a high voltage electric field to a particle. Provided the electrodes are at the same distance and relative location from the particle in any case, will it make a difference to the ...
51 views

### Calculate potential between two rods

Suppose we got four thin, long and parallell conductors with charges shown in the image below. Each conductor has a radius $r$ and length $l$ . Our problem is to find the potential between the ...
• 313
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### What is a volt?

How a volt is measured and defined in the simplest terms? What does it mean when you measure voltage using a voltmeter? In the past, we defined things by physical things. For example, the kilogram ...
129 views

### Human body communication, magnetic vs capacitive coupling

I am reading a paper by Park and Mercier called Magnetic Human Body Communication (2015). They are looking into human body communication techniques and compare magnetic human body communication (mHBC) ...
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60 views

### What are changes in field lines after two plates of capacitors are connected?

I recently came along to know about capacitors and their ability to store charges, also I studied about their electric field, I want to know what changes in electric fields will happen after we ...
1 vote
488 views

### Antenna polarization and loss factor

I am trying to solve the following problem: I know that in the +z direction: linear polarization requires the field vector to have: one component OR two orthogonal linear components that are in ...
565 views

### Can you charge a capacitor with very high voltage and no or little current from secondary side of a step up transformer?

Based on the research I did online and after reading basic electrical books I understand that a capacitor stores energy in the form of electric fields. So I understand that, to charge a capacitor, all ...
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156 views

### How does an electric field in a capacitor behave in an AC circuit? What does the E field look like for co planar capacitor plates?

Namely, is a "constant" E field changing direction at a rate of the applied frequency? Does the E field in coplanar plates looks like this? Is there a way to derive the Capacitance of this ...
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1 vote
42 views

### How can I find critical field in tsmc65 transistor parameter?

How can I find critical field in tsmc65 transistor parameters? Critical field is the field which electron velocity in transistor go into the saturation region.
266 views

### Significance of electric field for electromagnetic compatibility standards

All electromagnetic compatibility standards around the world for immunity to electromagnetic fields (radiated susceptibility test) mention the strength of electric field (V/m), but not the strength of ...
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### Why are the vertical deflection coils in a CRT deflection yoke so different from the horizontal coils?

Looking at a typical raster CRT deflection yoke, there appear to be two very different pairs of coils. There is the pair on the inside that curves outwards, and the pair on the outside, which are ...
126 views

### Why do we subtract horizontal and vertical component of a electric field?

I was solving a question of electrostatic which is: Find the electric field at a distance z above one end of a straight line segment of length L that carries a uniform line large lambda. My question ...
225 views

I have a question that my teacher was explaining but the question seemed to contradict the real world. I know it has got to be my understanding that is flawed but I cannot seem to get it. So here goes:...
825 views

### How can two identical charges affect a point when their fields lines never even touch?

If two identical charges were to be put beside each other, their field lines will not cross but rather go to infinity. In this case, if you put a point on any part of the two fields the other field ...
86 views

### Which electrode configuration should have the highest electric field produced?

I'm currently simulating the the electric field produced by different types of electrodes. The electric field is observed on the insulator that is sandwiched between 2 electrodes, one being 10 kV ...
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### Why don't most electrons hit the anode in a cathode ray tube or electron gun?

In a cathode ray tube or electron gun, electrons liberated from the cathode by thermal emission accelerate towards a ring-shaped anode, from the potential difference between cathode and anode. If an ...
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94 views

### Converging Electric Fields on Metal Plate

I have a question, but I'm not a trained engineer, just curious. So bear with me on my explanation. Let's say I have a metal plate. I have DC power supply and I connect the positive electrode on one ...
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918 views

### Finding the electric field due to a "point" dipole in different locations

I'm currently taking a course in Electrical fields and circuits and came across this example problem from the course book. I am having trouble figuring out how to solve it. Below you will find my ...
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### Can there exist an arrangement of charge densities that creates a loop in the electric field lines of force?

Can there exist an arrangement of charge densities that creates a loop in the electric field lines of force? In this answer, a poster writes: Note 2 5/8: superconducting loop A uniformly perfectly ...
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153 views

### How to determine electric field polarity from electric field mill signal?

I have built an electric field mill like this, more info can be found in the (short) wiki article: It works by exposing the sensing electrode to the ambient electric field, which (depending on E ...
• 1,137
118 views

### Electric field in a circuit and potential drop

With reference to the above image: Here the battery produces a constant (will it be constant? pl. explain) electric field across the length of the wire, lets say its value is $\vec E$ . This field ...
• 103
244 views

### Is the strength of an electric field the same throughout a conductor connected to a battery?

Is an electric field the same all over a conductor? As electrons move further in a conductor they start coming from high potential to low when moved from high potential end of conductor(cathode) to ...
1 vote
1k views

### Best shielding material for a Faraday cage against 36kHz electric fields?

I have a room aka cuboid with 4 x 3 x 2.5 meters. In the 3D center is a device under test. To shield against 36kHz electric fields I want to build a Faraday cage. I learned the hard way that aluminium ...
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436 views

I have a room aka cuboid with 4 x 3 x 2.5meters. In the 3D center is a device under test. To shield against 36kHz electric fiels I have built a faraday cage by sticking 0,012mm thin and 30cm broad ...
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1 vote
140 views

### The equation of surface charge density is incorrect with only the sign is opposite of capacitor of cylinder form

The capacitor of the 2 cylinders exists. As shown in the diagram, the righter space has been filled with the dielectric of $\epsilon_{1}$ and the lefter space has been filled with the dielectric ...
1 vote
816 views

### Distribution of surface charges along the wire

Distribution of surface charges with a constant gradient is present along the length of the wire which produces a constant electric field along the entire length of the wire. This results in constant ...
3k views

### Cable shielding adequate for video, but not audio frequencies

I am no expert in audio equipment, but to educate myself I have been studying. In the process, I came across a video which tests the audio frequency shielding of a purported shielded video cable. (I ...
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### How many newtons are there in one coulomb of charge?

Or, I should have said, how many newtons of force does one coulomb of charge exert? At a distance, presumably, of one meter? Since N/C is supposedly equivalent to V/m? P.S. What are the values for a ...
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### How can formal insulators "conduct" electric and magnetic fields?

Is there an explanation regarding the ability of an insulator between capacitor's plates to be permeable to an electric field? The terms "valence band" and "conduction band" the ...
183 views

### What is the Relationship between Magnetic Flux density and electric field intensity

I was given this question by a teacher and I have scoured the internet for a formula or solution to this question, all to no avail, the question says "in a certain region of space, the magnetic ...
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### A DC current through a inductor does not create electric fields

While studying about electric fields and magnetic fields I came across this picture: and this: from this website and it indicates that there is an electromagnetic field around the loop of wire, ...