Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [electric-field]

44 questions
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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 electron is slightly off-centre, so nearer to one…
sqek
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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 cannot attest to the fact that it is indeed a…
Math Keeps Me Busy
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Is the electric field in a wire constant?

If \$V=I\cdot R\$ according to Ohm's Law, that implies that \$\frac{\mathrm dV}{ \mathrm dx} = \frac{I \rho}A\$ across an infinitesimal length of conductor, which is constant at all points along the conductor since the current, resistivity, and area…
Ryan
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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 attempt. From the textbook about point-dipoles An…
NoName123
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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 magnetic field (T). An EM wave will have both…
Ronnie
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Capacitor in presence of an external electric field

Let's consider a capacitor made of a couple of parallel metal strips (suppose they are made of perfect electric conductor) as shown in the figure, which represents a little capacitor. Suppose an external (time variant) electric field is applied in…
Kinka-Byo
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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 testing levels of other products I've made - however,…
Mister Mystère
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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 quite get how to do part c(ii). The mark-scheme…
rk1506
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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 field strength (not asking about the current)…
Oliver Walters
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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 you need is electric field, you do not need…
Yogie
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How to measure the potential gradient between large capacitor plates?

I have built a capacitor for a biology experiment, but I need to measure the potential gradient between the plates. Mainly I am going to apply an AC current between the capacitor plates to have an oscillating electric field, but I would also like to…
Tsangares
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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.
mohammad rezza
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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 foil does not really work so I am asking now…
Hansebenger
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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 of \$ \epsilon_{2} \$ What I want to do is to…
electrical apprentice
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How to redirect electric field lines with a copper plane

I have been testing a capacitive sensing circuit in which an electric field is projected vertically to sense a finger (a grounded conductive object). On the PCB, a tx and an rx are 2 copper structures that act as the 2 plates of a variable…
JCSB
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