Questions tagged [electromagnetism]
The kind of magic without which all of this wouldn't be possible. This tag should be used for questions about the **physics** of the fields that charged particles create and how these fields interact. It should not be used for all questions involving electromagnetism; that would be everything on the site.
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Nominal current for my design using AA battery
I am designing an electromagnet and I'm deciding on the wire gauge to wrap my coil in. It's going to be powered by 6V batteries (using 4 AA 1.5V batteries).
The problem is that I used a current of 0....
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What happens if two wires intersect [closed]
I'm pretty sure electric currents don't interact like this but if I were to make a NOT gate, with a wire, where one point is where current comes from and the other point be an output and the wire is ...
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Finding the ideal parameters for a homemade electromagnet
I am making an electromagnet and I was watching some videos on designing one. I just have some misunderstanding about power calculations of electromagnets and I have some questions about it.
Q1)
1.1) ...
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Electromagnet design and powering it up? (Fault prevention of DC supply for a small coiled Electromagnet)
I want to create an array of multiple electromagnet which I will be controlling using a microcontroller.
I will have around 100 such magnets lined in a squared grid 10x10. Only three or five at a time ...
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How do steel laminations reduce eddy current losses in a transformer?
All online materials I have read so far state that laminations reduce eddy currents but how is this so? I mean why would currents be smaller this way than having a big block of unlaminated iron core ...
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Shielding bottom of PCB in THT design
I'm designing a PCB where I could use one layer as massive groundplane and shield. Do I have to make some form of shield for THT part pins, or are they small enough to not pickup a lot of ...
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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 ...
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Does the law of reciprocity hold true for the phase response of an antenna?
I know that an antennas spectral transfer function should be the same in both transmit and receive due to the law of reciprocity, however does this law hold true for the phase response (AKA phase ...
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Problem acquiring B-H curve
I'm trying to acquire the BH curve of a toroidal current transformer in saturation, having the primary and secondary current.
The formulas I am using are:
B = (1/NsS) Integral(Vs(t)dt)
H = (Ip*Np)/l
$...
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Signal diode to protect high speed data lines
I don't understand this. Could someone explain this to me? I have a hard time imagining how it works. Why would the signal line be protected by connecting the diodes this way?
If you get an ESD event ...
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How to connect a 12V electromagnet to 220V power adaptor
I'm not very familiar with electronics, but I want to create a basic automatic pet feeder for my outdoor dog house. My idea is simple: a wooden box with a floor that drops at a set time, controlled by ...
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Reverse electrowetting on dieletric using air bubble displacement for electricity generation
I read this research paper and it uses bubbles to change the electrolyte and electrode interface, thus causing a change in capacitance as the bubble forms and exits the electrolyte.
For reference: ...
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Yagi antenna with 16 dBi gain, is it bottle necked by the power input?
I want to expand my PC's WiFi range, but the NIC delivers only 5 W. When I connect the antenna, not much more range is achieved. Is the antenna not the right one, or is the output of 5 W not enough? ...
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Electromagnetic Energy Harvester
It was suggested I make a new post since the topic was growing in complexity.
I am looking into constructing an inductor to utilize electromagnetic induction near a high voltage transmission line. If ...
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Magnetic interaction between resolver & motor windings?
Scenario: Synchronous electric motor whose rotor position is measured by a resolver.
Won't the magnetic field created by the motor stator & rotor, link with the primary & secondary windings ...
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Expression vectorial to magnetic field \$\vec{H}\$ in infinite semi-plane conductor
I have some difficult to figure out the second expression about the contribution of magnetic field as you see below:
Problem:
A wire conductor, infinite long (Z axis), conduct a current constant equal ...
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How can I read a high frequency PWM falling edge with Arduino interrupts?
My project is about a Magnetic Levitator. I control the electromagnet with a high frequency PWM signal which I use on the MOSFET gate to give to it enough current.
The thing is that I use a linear ...
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Undesired oscillation in an electromagnet control system causes the levitating object to fall
I have been struggling with a college project, being so close but yet so far from making it work succesfully.
I have designed an electromagnet control system that has to control the position of an ...
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Electromagnetic Pendulum Pulse Driver - Having Trouble Getting Circuit Running
Now I'm not super well versed in circuits though I've dabbled a bit in some circuit building in the past. I'm working on an electromagnetic driven pendulum for a clock I'm building. The Schematic I'm ...
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Troubleshooting thermionic emission
I am attempting to make an electron beam device work. The setup is very basic - a wehnelt in a vacuum chamber connected to an AC filament heater source and a DC high voltage source as pictured below. ...
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How is the holding force of this electromagnet so large?
I am designing a system that uses the magnetic force to fix an object in its place. I plan to connect an I-core to my object and fix it to a fixed C-core by letting a magnetic flux flow through both ...
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Question about RF waves and it's effect on electronic devices
Could a let's say 50 W RF wave (2.40 GHz and 5 GHz) cause disturbance in nearby devices like Laptops? (Data corruption, random opening of applications and programs, random commands, etc.)
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Electromagnet doesn’t have power [closed]
I have so problem with an electro magnet, I mean it seems a little weak to me. What could I do to improve it’s power? Battery: 3.7V 8800mAh
Also, I had the wires in small parts so that’s the reason ...
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Energy regenerative snubber for flyback converter
I am trying out the regenerative snubber design in https://core.ac.uk/download/pdf/215381319.pdf page 13. The circuit configuration is shown in the figure below:
I am unable to derive the following ...
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The idea of voltage in the ideal inductor equation
In a book that I have been reading (Practical Electronics for Inventors 4th ed by Paul Scherz and Simon Monk), I came across the equation on pg 129 for for inductor $$V_L = L \frac{di}{dt}$$
where $$...
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Converting air compressor to gas but leaving ac motor on
I have a compressor with the crankshaft being the the front part of the shaft of an A/C motor's armature.. The rear of the AC motor's armature has enough protruding shaft to put a pulley on it and ...
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Why is resistance (inversely) proportional to area instead of circumference?
TL;DR From the Veritasium-vs-ElectroBOOM debate about the 1 m / c question, it seems to me that most properties about conductors depend only on surface charges. So shouldn't quantities like resistance ...
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How can a transistor behave as a switch in the saturated region
how can a transistor behave as a switch in the saturated region when it is in forward bias mode in the saturation region and the collector current may become zero,
when a transistor is used as a ...
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Does operating an iron core near its saturation field reduce performance?
I am sizing an iron core for an electromagnet, and I am uncertain if there are disadvantages to operating close to the saturation flux density. If the saturation field is X, would it be better (more ...
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Reflection coefficient of a transmission line with discontinuity
I have a question, let's say that we want to calculate the Reflection Coefficient that we see by watching from left to right of the red-line this circuit:
Let's say that:
Za= Equivalent Impedence of ...
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Propagation speed and capacitors charging speed of transmission line
I am a bit confused on the speed of voltage propagation in the transmission line and I hope someone can enlighten me. I understand the speed of step up voltage propagation is in the same order as the ...
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Problem understanding lossless T-Junction divider
I am studying how the lossless T-Junction divider works. I am going to assume that the susceptance in the junction is 0 for simplicity, and it is not relevant to my question.
The structure of a T-...
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FEMM simulation not returning expected force from electromagnet
I have an array of 8 air-cored electromagnets. Each one activates sequentially(with previous ones staying activated) to pull the N42 Neodymium magnet array to the end of the array, with the force ...
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HV and LV transformer coupling not working, no current from LV transformer?
I am trying to couple a high voltage transformer (automobile coil) 220 V to 10 kV, with a low voltage home made transformer 220 V to 6, 12 V (think MOT but bigger).
I have tested/used the LV ...
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Are transistors on MMICs considered lumped elements?
Are transistors, in practice, always small enough to be considered lumped elements in Monolithic Microwave Integrated Circuits (MMICs)? Similarly for discrete transistors used in hybrid microwave ...
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How do I find the torque of a simple electrical motor?
I created a simple electric motor following Khan Academy's tutorial, and now I am trying to figure out how I can find the torque from it (which should be quite small).
Here is an image of the setup ...
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Is Lorentz-Force the same as electromagnetic force?
I have been doing some research on the Lorentz force law because I am currently learning about AC and DC electric motors. I have been stumbling onto the phrase "electromagnetic force" and &...
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Visualizing current flow in transmission line
This may be a trivial question, but I am not sure how current flows in certain types of transmission lines. Consider for example a coaxial cable working in its TEM mode. The wave travels perpendicular ...
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Coil winding direction in a shaded-pole motor (4-pole)
I have rewound a shaded-pole motor (4-pole).
It's wound around the stator in a clockwise motion and around each coil in a counter clockwise motion.
Is the winding being incorrect the reason why the ...
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Want someone to review my Helmholtz coil design to see if I am missing something obvious before I fabricate it?
I am planning to construct a Helmholtz coil and wanted electrical engineers to take a look just so I know I am not overlooking anything.
The max field strength I am looking for is 200 Gauss. I ran ...
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Calculate inductance of a coil with an iron core inside
I want to calculate inductance of a coil with an iron core inside. The iron core is not vertically centered, but it is still aligned along the axis of the coil.
I know that FEMM softwares and ...
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Is the current that is on the surface of the area surrounding a current carrying wire in Ampere's Law the same as what flows in the wire?
I am OK with the first 3 of Maxwell's equations but on the 4th equation I need to first figure out Ampere's law. What is confusing me is the surface of the area that is surrounding the current ...
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How does this motor work?
I have been on a bit of a quest to find some sort of linear motion device to compress a spring with 15kg of force 80mm at 1600mm/s, with continuous duty cycle, ideally under $40. So I was digging for ...
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Linear Motor Design
I previously uploaded a question on trying to make a solenoid attract a magnet 80mm away, however this ended up being an impossible ask due to solenoid's having a max effective attraction distance of ...
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Strong Compact Solenoid Design
I have a spring that I need to compress 80mm. To do so requires approximately 15kg of force. To compress the spring, I will have the spring in front of a piston head. The piston head will have a ...
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How can a wire be influenced by a electromagnetic field?
I have a problem in one of my project. Here are some details:
A train is moving on tracks. To know its location, some beacons (transmitters) were placed at different locations in between the two ...
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What role does permanent magnet strength play in BLDC/PMSM performance?
It seems to me like stronger permanent magnets are preferred by motor designers, but my current understanding of what role they play in performance is fuzzy at best. I would assume that stronger ...
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What types of inductor cores exhibit magnetization?
My understanding of magnetization in core memories is as follows: a bit is written to an inductor's core by magnetizing it, by applying a large current. Later, the bit is read by observing the effect ...
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Predicting EMI/EMC Issues from Microcontroller AC Spec Rise time fall time
In one of his video Rick Hartley says signals with fast rise time can cause EMI/EMC issues.
I am using FS32K148UJT0VLQT in my design. In my board this controller is working at 5 V supply.
Below image ...
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Park transform, why do we use the electric angle and not the mechanical angle?
In the control of a motor with a multi pole-pair permanent magnet rotor the Park transform is done (if I am correct) using the electrical angle, and not the mechanical angle.
If we use the motor as a ...
