Questions tagged [field-strength]
The field-strength tag has no usage guidance.
50 questions
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How does EMF strength decrease with distance from a power transformer? [closed]
I'm trying to understand how electromagnetic fields (EMF) decrease with distance from a power transformation station. If the EMF at the station's outer wall is around 150 µT, how far would I need to ...
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Core iron barely boosting field strength
I am a chemistry intern currently running a project that involves both chemistry and electromagnetism. Bottom line, I'm a little out of my depth and have much to learn, and I'm having a bit of trouble ...
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How to calculate the voltage and / or current in a crystal radio?
I have thought of using V=E*d for the voltage across the antenna (d being its length and E the electric field strength of the incoming radio wave) and then use I=V/Z with Z being the total impedance ...
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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?
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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 ...
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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 ...
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Are those electric fields dangerous?
Is 8.6 amperes per meter, 70 microtesla, 0.70 gauss, 695 milligauss, safe on long time exposure?
I am just worried.
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How to modify RF field strength meter circuit to attach signal strength meter? [closed]
Figure 1. 7.023 MHz RF field strength meter
Figure 2. Signal strength meter
What kind of modifications do I need to make to this RF field strength meter circuit, to attach the signal strength meter?
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Contradiction in Gauss's law?
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:...
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How can one calculate at surface the electric or magnetic field strength for 50Hz 240VAC wire at 1 meter depth?
How can one approximately calculate at surface the electric or magnetic field strength for 50Hz 240VAC wire buried at 1 meter soil depth for a given current?
Say in sandy clay soil with no mineral ...
user132893
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Estimating Received Signal Strength of a DTV transmitter
Goal:
Estimate the received signal level in dBm (where 0 dBm corresponds to 0.224 volts) on a spectrum analyzer for a given TV transmitter.
Scenario:
I have many details on the transmitter, including ...
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Why EIRP has denominator factor 30 in the formula?
I am calculating the EIRP using FCC guidelines. I came across the formula in the FCC guidelines that has a denominator value of 30. That is, EIRP = (E x d)^2/30. Can anyone explain what 30 is and ...
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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 ...
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Help understand the role of an inductor and its value (educated guess)
This circuit is a part of a field strength meter circuit in an old magazine, the value of inductor J1 is unknown (due to a print error in the magazine.)
The circuit works like this:
With S1 open and ...
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Using Quickfield LabelMover to extract specific local values at coordinates
Quickfield Student Edition
I've attempted using Quickfield's LabelMover Serial Analysis to automatically get local values of interest at a set of different specific coordinates, but I couldn't find a ...
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Maxwells Equation in Time varying field
The Maxwells Equation giving the value of Magnetic field (B) for stationary and moving coils are having different variables. How is the third equation possible with such 2 cases?
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how do we get these three formulas from the definition? field strength
I believe these three equation in the figure are not the definition of field strength,and the definition of field strength is \$H=\frac{F}{m}\$,how do we get these three formulas from the definition?
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When a coil is wrapped around a ring of non magnetic material, is the path length (l) the circumference or the diameter of the ring?
I'm doing some practice questions on magnetic fields:
A coil of 300 turns is wound uniformly on a ring of non-magnetic material. The ring has a mean circumference of 40cm and a uniform cross-...
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Pancake Coil Magnetic Field Strength
I am trying to measure the magnetic field strength of a pancake (flat) coil. I know the turns, inner radius, current, and frequency from an AC input and am trying to measure the magnetic flux so I can ...
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How strongly does patient movement affect the magnetic field in an MRI? [closed]
The magnetic field in an MRI is insanely stable due to a closed current loop in the superconductor. A normal conducting magnet would always have (in addition to a ridiculous power consumption) power ...
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Electric field strength from AC conducting wire in form of a loop along z-axis?
Let's say I want to calculate the electric field strength from a wire loop carrying AC of given frequency and current. I want to calculate the E-field along the symmetry axis (z-axis) of that loop of ...
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How to convert A/m to dBμA/m?
Lets say I have -2 dBμA/m as a limit.
How do I convert the magnetic field strength in A/m to dBμA/m? Is it as follows?
$$20\cdot \log(\frac{ |H| }{10^{-6}})$$
Thank you!
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Does a wider magnet mean less flux density?
I was using an online magnet strength calculator when I halved the diameter of the theoretical N52 magnet. The dimensions went from 32mm in diameter and 3mm thick, to 16mm in diameter and 3mm thick. ...
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How can I measure an AC magnetic field using a linear Hall effect sensor with an Arduino?
I have a SS49E Hall effect sensor. I want to measure the magnetic field in gauss using an Arduino analog output. I have code for analog applications but is this appropriate just for the DC magnetic ...
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Magnetic field strength and flux density from hysteresis curve
I am trying to measure the magnetic hysteresis curve of a toroidal nanocrystalline ferromagnetic transformer core made of Nanoperm (datasheet linked) using the following circuit. Each of the windings ...
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Skin effect of copper in a high-strength AC magnetic field
I'm trying to determine the thickness of copper foil required to construct an enclosure that attenuates a very fast-rising, very brief pulse of AC magnetic field at a frequency of 1 MHz and field ...
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Energies carried by electric and magnetic fields in plane waves
This is a newbie question. I'm trying to understand what I think must be a very basic concept with an obvious answer, but I want to be sure.
Do plane wave electric and magnetic fields of equal ...
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Small SMD components: are they really capable of withstanding high voltages?
You can easy find some SMD components which are pretty small for such a high voltage (500V @ 0805 package for example - crazy?!). 0805 case would have 1.3 mm distance between the contacts, so I doubt ...
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Electric Field electrical charge
Hey i dont know how to solve this. Can somebody help me?
In the two-plate arrangement shown in the sketch, there is homogeneous electrical field strength
$$\vec{E_0} = -\vec{e}_y * 10\frac{kV}{cm}$$
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Calculate work done to remove a electron at the above position from nucleus to infinity
i'm doing this question and I'm at the last part now. The first question wanted me to find out the electric field strength (r= 3.0x10^-10m, q= 9.6x10^-19C) and i used coulombs law and i managed to get ...
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EMI Field Strength
I tried to look up this kind of question in the archives but didnt find much usefull information. I also have another question in regards to EMI but I will ask this later in a seperate post.
...
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How to calculate electrical power needed to produce a given electromagnetic RF field?
What Electrical Power (watts) needed to produce the electromagnetic RF field intensity (strength) ≈ 60V/m? How to calculate electrical power needed for a given electromagnetic field strength value? RF ...
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Equipment to measure strong constant (in time) and slowly changing electric fields
I would like to measure the electric field in the vicinity of an object of interest. I would like to have decent spatial resolution (i.e. be able to pinpoint a measurement to a point in space within ...
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FSPL formula for near magnetic field?
I would like to know the precise formula for the Free Space Path Loss in case of a Magnetic Field in the Near Field region.
We all know the popular FSPL formula, but this is only for the far field, ...
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EIRP and Radiated Field Strength
I have a question regarding Field Strength: I was told it is independent from the frequency, is that true? If so, why?
Moreover, I came accross this equation for converting the Field Strength to ...
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Calculate field strength for shielded isotropic transmitter
How to calculate the field strength of a shielded theoretical isotropic transmitter, if there is a hole in the shield for example.
I am looking for a complex formula that also takes into account the ...
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How to transform field strength as a function of frequency
According to the EN 55022:2006 standard max electric field strength should be:
40 dBμV/m for 30–230 MHz
47 dBμV/m for 230–1000 MHz
I am a little bit confused, I don't know how to calculate the ...
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Formula for Field Strength
According to this document on page 3, the formula for Field strength is stated as follows:
I can't find reference to this formula elsewhere and was wondering if someone can verify this is correct, in ...
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IR signal strengh measurement
I have an application where I have multiple IR transmitters/receivers set up to read data. These are removable and can be set up in a lab environment where I can control distance, light, etc. I've ...
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Relationship between electric field at aperture and field at distance
I'm new to this forum and turned here because I have no other help to turn to. In studying antenna theory and I came across the relationship between E0(Electric field at aperture) and Er(Electric ...
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Measure AC magnetic field strength between 100kHz and 300 kHz
I have tried to find in the webpage some answers about measuring AC magnetic field strength in the range above 50 kHz and more with no luck. Sorry, but if someone could help me will be great.
I need ...
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Conversion from dBm to Volt/ meter
I have no experience with electronics but I have a question.
Actually I'm using a circuit for a project that is able to measure RF power at its input in dBm; the circuit provides the integration of a ...
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Calculating Field strength of a air core solenoid
I want to build a magnetizer for charging / magnetizing small alnico magnets for that I am thinking to discharge a cap into a air core solenoid.
The magnet to be charged would be kept within this ...
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Forensics: electrostatic detection circuit for lifting "indentations" from documents
Wikipedia explains that an EDD:
...is a specialized piece of equipment [used to] reveal indentations
or impressions in paper which may otherwise go unnoticed. The
electro-physical basis whereby ...
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Fetch RSS value using Nordic NRF24L01 module and RadioHead library
RadioHead provides a lastRssi() function (http://www.airspayce.com/mikem/arduino/RadioHead/classRHGenericDriver.html#ab04f2ca335d89f5fac1d213c0aea9da2) to fetch the ...
user107839
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Question about electric fields [duplicate]
Ok so I have this question:
Two point charges of charge -2 µC and -3 µC respectively are separated by a distance of 15 cm. Point X is positioned at an equal distance away from each of the charges.
<...
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Question about Coulomb's law
I am just very confsed about how to do these sort of questions where they give you a point in the middle of two charges. The farthest I've gotten in questions relating to coulomb's law, is using the ...
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Dispersal of radio energy as it moves further away from the source
I apologise for the wording of my question, it will no doubt come across as confusing. If there is anything you are unsure about please feel free to ask me.
Question
As a radio wave moves further ...
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\$2n\$ point charges on a circle at \$O\$, what's total electric field intensity \$\overline{E}\$ at \$\pm 1\mathrm{m}\$?
The problem reads is from a Schaum's Outlines of EMFT and reads:
A total charge of \$1\mathrm{nC}\$ is equally distributed among \$2n\$ points which are placed equidistantly on a circle with \$1\...
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how much voltage pass through antenna? [closed]
I want to know how much maximum voltage can be generated on a receiving antenna.
Also, please help me to find an antenna design with maximum received signal voltage; I dont have proper knowledge of ...
