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 ...
1
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0answers
13 views
Electromagnet interference with motorcycle
I just got a sport bike which the frame is aluminum the engine is aluminum the swing arm as well. Basically this bike is made up of mainly aluminum and plastics with very little steel or any other ...
1
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1answer
75 views
Does heat affect the magnetic field of an electromagnet?
I know that heat destroys perm magnets, but how about electromagnetics? Does heat affect the strength of an electromagnetic field?
5
votes
1answer
81 views
Controlling an electromagnet strengh with arduino
This previous question Controlling an electromagnet with Arduino deals with binary control (ON or OFF) only.
On my side I need to choose the strength of the magnetic field.
It is a home made ...
11
votes
5answers
377 views
Why does a simple conductor start to emit EM waves when carrying a signal?
I understand that on circuit board traces with a clock, if the higher harmonics have sufficient power, it results in electromagnetic waves being emitted from the traces which creates EMI. What I don't ...
-4
votes
1answer
63 views
Why can't we record amp sounds from line out of amps when we can hear in headphones using line out? [closed]
Suppose there is electric guitar, and we connect it to amplifier (amp). When we connect our headset into line out of the amp, we can hear what we are playing. If so, why can't we record the sound out ...
0
votes
2answers
78 views
PWM controller to meet EMI/EMC regulations
I'm designing an application in which the current running into a load is controlled by PWM.
A microcontroller generates a PWM cycle at 20kHz and this signal is used to control a MOSFET which is ...
1
vote
0answers
120 views
Does living near a cell tower decrease your overall exposure to RF? [closed]
I understand that my mobile phone will increase its RF levels when it struggles to connect with a cell tower/base station due to distance. Also being nearer a cell tower will increase my exposure to ...
5
votes
4answers
147 views
How do arcs generate radio-frequency
When I have an electric arc, and put an AM radio nearby, I hear a crackle and the station that I previously heard goes away. I am wondering what is going on with the electricity through the air to ...
4
votes
5answers
141 views
Are E and B fields in phase in electromagnetic radiation?
I recently wrote this answer, in which I said:
Radio waves are electromagnetic radiation. Electromagnetic radiation contains of two components, one electrical and one magnetic. These components ...
5
votes
5answers
182 views
What is the difference between electromagnetism and electromagnetic radiation?
In a previous question, I asked if having 2 coils of wire with electricity flowing from one to the other is RF, and they replied that it was not Radio Frequency. I was puzzled because I thought this ...
0
votes
3answers
141 views
Voltage and Current relationship in generation
Please could someone explain why the current is 180 Deg out of phase with the voltage when measured at the generation point and then in phase with the voltage when measured at the load point. I am ...
1
vote
1answer
116 views
Amperian loop to measure solenoid's magnetic field
My textbook proves the formula \$B =\mu_0In \$ for a solenoid by taking a rectangular Amperian loop as shown here:
The problem I see with this though is that it only takes into account the ...
-4
votes
1answer
49 views
On Electro-galvanic fuel cell [closed]
Hello for every one ,
my close friend is going to design some of Electro-galvanic fuel cells , and he seeks for more information about it ,
how does it work ?
what are the laws of physics which ...
1
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1answer
74 views
Terminals of three phase power machine
A three phase machine, instead of having six terminals, two for each slip ring, has only four terminals. Because the starting point of all the three coils have a common junction which is usually ...
0
votes
1answer
88 views
Can someone explain impedance in simplest way? [duplicate]
I know in DC it is Resistance of the load.
In AC is it impedance of a line correct? can someone please help me understand impedance and types of impedance.
Zero Sequence, Positive sequence and 2 ...
0
votes
2answers
136 views
On using an electromagnet in a magnetic stirrer
What's the simplest and cheapest way to use one or more electromagnet to to stir a stir bar ? That is, how to control the speed at which the polarities are reversed.
I don't want any mechanical part ...
-3
votes
2answers
70 views
Inductive Braking System [closed]
In a traditional braking system, brake pads produce friction with the brake rotor to slow or stop the vehicle. In an inductive Braking System induction is used to extract energy and act as a brake. ...
0
votes
1answer
90 views
ElectroMagnetic Induction
there is already a electromagnetic brake. I'm thinking to use a electromagnetic induction as brake. is it possible?
0
votes
1answer
181 views
magnetic field outside solenoid
It is written in our course book that the magnetic field outside a solenoid is negligible and almost zero. Why is it negligible? Is it negligible compared to the field inside solenoid or is it nearly ...
1
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0answers
50 views
How do construct a electrical resistance tomography apparatus
Im interested in constructing an electrical resistive tomography setup to image underground structures. While I somewhat understand the principle, I have found limited information on design and ...
7
votes
0answers
205 views
Differences between a planar coil and coplanar waveguide to create a local 1D AC magnetic field
Coplanar waveguides (for example picture look here) are often used in research to create a local in-plane magnetic field. Now if compared to a planar microcoil like this,
driven by a AC voltage in ...
0
votes
1answer
119 views
what type of armature i should use in 12v dc magnetic 2 pole motor to get more than 8000Rpm
i m trying to wind a motor but i am new at this so can any one can tell me how can i wind an armature to get more than 8000 Rpm in a 2 pole magnetic motor
of 12 volts
6
votes
5answers
474 views
Suggestion to electrically disable a Faraday Cage
My plan is to ultimately develop an Autonomous Faraday Cage. The project seems very straight forward; however, I am unsure on how to effectively control the cage (turn on and off).
I have constructed ...
0
votes
0answers
30 views
Electrical Displacement Transducers
Please can you clarify for me what responsivity, maximum range and
linear range mean in relation to an electrical displacement transducer?
edit: I know now that responsivity is just output/input ...
2
votes
2answers
128 views
Electrical circuit / transformer in series?
I would like to pull out 5v 3A max in series from an already existing connection from the mains 240v 40A connection.
Current circuit:
What I would like to implement:
What are the possible ...
2
votes
1answer
80 views
Pros and Cons of 3 Different Transducers
What are the pros and cons of using these different transducers?
I can't find see what the difference would be between either of them? I mean, they are all used in converting energy right?
Linear ...
14
votes
3answers
480 views
In a DC motor, is there one commutation point that is optimal in all respects?
This recent question got me thinking about commutation timing, and why advancing it can be desirable. However, I wanted to consider more deeply the underlying phenomena, and I'm pretty sure my ...
-4
votes
2answers
156 views
Kill with voltage [closed]
Is it possible to get so much volt in you, that you become capable of killing another human being
Example: the game ''infamous''. In the game, you are literally living on volts.
So my question is ...
6
votes
3answers
236 views
Is it valid to consider back-EMF in a DC motor equivalent to increased inductance?
I know that back-EMF can be considered as a voltage source in series with the motor which is proportional to speed. This is the common understanding, and I totally get it. Before I understood this, I ...
1
vote
2answers
133 views
Dirty electricity filters how do they work?
There are videos on youtube about finding sources of high EMR. In this videos they reduce EMR level by plugging some 'dirty electricity filters' in wall outlets. I ...
0
votes
1answer
172 views
Calculating what frequencies a dielectric can be considered perfect
I have a problem that is likely going to be on my E&M final this semester that my classmates and I can not figure out how to solve. The question is
At what frequencies can Earth be considered ...
0
votes
1answer
118 views
Electrical Generator Windings - Is there an “ideal” way to wind?
I've got a question that's been bugging me for a while. Is there a "best" way to position a magnet and wire coil inside a generator? I saw a "how-to" on how to build a wind power plant and they had ...
2
votes
1answer
260 views
Open Source or free electric field mapping software
Looking for recommendations for 2D (or 3D) electric field mapping software. I want to be able to populate a series of electrodes in a plane and understand the equipotentials present when these ...
1
vote
0answers
66 views
How can I find the stored energy in a 2d triangle that has a different electric potential at each point?
I am writing a FEM solver for a project. I need to calculate the total energy stored in my mesh so that I can compute the capacitance of the solution.
So obviously I have to loop through all the ...
1
vote
1answer
140 views
emi standards/best practices for PC cases
According to an EE friend, the FCC specifies EMI tolerances (max outputs) for PC components, including cases. However, here it says that there are standards for a number of components but not cases.
...
1
vote
1answer
83 views
What characteristics of magentic coil is the most important for VLF sensitivity
I try to sense a VLF magnetic field (1-100Hz) by using a coil. The field is very weak and in most of reading there is too much noise. Is there the most important characteristic of the coil, should I ...
3
votes
3answers
400 views
How to convert a three wire hall effect sensor to a 2 wire sensor?
Would there be any possibility to convert a three-wire hallsensor to a 2-wire equivalent.
The connections are a V+, GDD and OUT.
The voltage between V+ & GDD would be 24V and the OUT port would ...
6
votes
1answer
207 views
Faraday Cage - Detecting one
I am looking for a cheap and easy way of creating a small electronic device that is capable of detecting whether or not it is inside a Farraday Cage.
Hopefully, without an external sensor/emittor.
0
votes
0answers
177 views
Electromagnetic radiation from specific monitors [closed]
I'm concerned about the health impact from EMF produced by home/office appliances. In particular I would like to know if somebody measured the Electromagnetic radiation of any of the following ...
4
votes
4answers
221 views
M.S. Math to Engineering Ph.D : Mathematics in Electrical Engineering
I have two Bachelor's degrees. One is electrical engineering and the other one is mathematics. I am studying mathematics (partial differential equations) in the graduate school (Master course) now. ...
1
vote
1answer
221 views
How to determine the force of a solenoid based on inductance
I'm looking to potentially build my own small solenoids, I thought perhaps that I could take an Air core inductor, a spring, piece of plastic, and conductive core and build my own. Is there a way to ...
0
votes
1answer
312 views
Multi-tap transformer current handling capability
I have a transformer with a single secondary winding but with multiple taps, as shown in the image.
It is rated at 4A @ 24V (96VA).
Does this mean that at lower voltages (16V and 8V) it will be able ...
2
votes
1answer
115 views
Automobile ignition coil (spark coil)
Question: How is this possible to get 1:1000 electric potential scale while primary/secondary loop scale is only about 1:100?
2
votes
1answer
170 views
Controlling temperature of a water bath with induction plate
I am thinking of building a sous-vide cooker using some kind of prebuild heater, controled via an AVR and temperature sensor like the LM35. There are a lot of references around using rice cookers, ...
3
votes
3answers
207 views
How is electricity typically generated?
I am a pure physics guy, so I understand the fundamental processes behind the generation of electricity, but I'd like to know how to apply it. I was wondering what kind of methods were used in the ...
8
votes
1answer
169 views
What is the dielectric constant of a fly?
Kind of a random question, It has been a topic of debate in my lab. I guess the more specific question is: what materials is a fly's body made out of, and what are their dielectric properties?
0
votes
1answer
206 views
Building a coil for galvo motor
I'm building myown galvo motors and for that I need some coils that I'll have to build myself to fit into the dimensions I need.
Is there any technique for winding the wire or is it just straight ...
4
votes
2answers
190 views
Why don't my coil work?
I disassembled my old Niko RC car today. Thought I could play around with the parts.
But what I can't seem to understand is the coil. The powersource of the rc car is a 7.2v NiCd 620mAh battery. And ...
0
votes
2answers
112 views
How do I get this spool to work?
I have this spool (image) and did some testing with a multimeter before I disassembled it. It's working range was [-3.3v,0v,3.3v]. When I tested it by just applying the battery after disassembly ...
2
votes
2answers
318 views
Magnetic door lock
I'm looking at buying an AEM10010 magnetic door lock (see page 4 of datasheet), but can't figure out how they're driven. The datasheet doesn't say anything about how to connect them, nor does it ...
