What is physically impeding electric current when a transformer steps up voltage? Is there some EM field along the conductor impeding electron movement?  FYI, I'm not asking about losses or leakage. (assuming ideal transformer) I'm trying to get an electromagnetic explanation of how increasing turns on the secondary winding exchanges current for voltage.  Thank you.
61129
I am happy to always not understand how does a transformer works ... One answer give me 10 questions ... (So I suggest you to not answer to this question, if you do not want to have more questions :D)  Here is the circuit :     So I put the "coupling" factor to 1, in order to have no leakage inductance and I set the value of the inductors very high in order to have a very low magnetizing current. So the primary current is approximately equal to the secondary current. My question is the following : How the primary current can reach an equilibrium to be equal to the secondary load current ? I will not accept answer which tells Pout is equal to ... So Pin is equal to Pout... There is something happenning into the transformer ...   Thank you very much and have a nice day !
88452
I came across this statement while studying electric currents and I am confused:  "There is no electric field inside a conductor. Hence no current can flow through it".  Is there a fallacy in this statement?  Any help would be appreciated.  The conductor being discussed is ideal. What is the driving force for the current in this case?
60243
I saw a battery charger that converts 220V AC to 6V DC without a transformer.   Now I am wondering why many (if not all) power adapters are using a transformer, is it about efficiency or about drifting over time?  Update: This circuit is inside of this torch
75023
I'v heard that a delta/delta or Wye/Wye transformers do not make any phase shift. In delta/wye or wye/delta transformers, There is a 30 degrees phase shift between the primary and secondary coils. So, Why is  there a phase shift ? and Why is it 30 degrees ?.. Why not 60 or 120 ?  I googled and I found calculations with phasor diagrams that proves the 30 degrees phase but I'm confused because of too many calculations and diagrams, I didn't get it.  Would you give me a simple answer, please ? and I prefer the physical meanings and concepts rather than equations and mathematics.  Thank you very much,
40509
Designing the power supply for an radiation detector, need to supply up to 1500V at 2 mA from mains (170 Vdc).  I've largely considered a flyback converter, but cannot find a flyback transformer with a gain of N=~16 (for a gain of 8 at 50% duty cycle) rated for 1500V at the output winding.  Looked into charge pumps/voltage multipliers some but not in depth yet.  Also just recently learned about CCFL inverter transformers, but still need some time to understand them better.  This project requires a small size and weight, so using a large transformer is not preferred.  What are other ways to step up voltage which I may look into?
54473
Keeping it simple, what is the physics approach to a current in a wire connected to a battery? How does the electric field behave?  I've read somewhere that, contrary to the common conception, electrons don't really flow as water in a hose so, what is really going on there? How is energy transported at the speed of light if electrons don't flow like very fast water?
114501
Moving a magnet close to a conductor induces a current. If it consists of a superconducting material with resistance $R=0$, then my textbook says:     Then the induced current will continue to flow even after the induced emf has disappeared.   This makes sense physically - there is no resistance to stop charge flow. But then the book draws this conclusion:     Thanks to this persistent current, it turns out that the flux through the loop is exactly the same as it was before the magnet started to move, so the flux through a loop of zero resistance never changes.   If the flux $\Phi$ never changes in a superconductor, from Faraday's law this means - from what I have learned - that no electromotive force $\mathcal{E}$ is induced:  $$\mathcal{E}=-\frac{\mathrm{d} \Phi}{\mathrm{d}t}=0 \:\:\:\:\text{ when }\frac{\mathrm{d} \Phi}{\mathrm{d}t}=0$$  My conclusion is therefor: There would never be induced any current at all. Current can never be induced in a superconductor loop. Is this the case or am I misunderstanding my book?
46410
I get confused on the low-level physics of electricity from time to time. It came up in "," and I don't totally get it.  How fast does electricity flow? Is the speed of an electron different in say a resistor than in a wire? Does it matter? Or are the effects of the electron the only important thing, with lower levels of abstraction not useful in practice?  I know there are already materials on this topic, and I have read some of them. I think having the question on this site might inspire some interesting answers to the age-old question.  Bonus points for:   Identifying and clearing up common misconceptions Explaining in a way that someone with a high school diploma could understand, without oversimplifying it so much that its incorrect
114389
How is using a 1:1 transformer safer than using the mains straight off? Is it because you can limit the current coming from the transformer whereas straight from the mains its not current limited? I fail to see how its "safer" when playing with electricity is dangerous. Could someone please explain why it is considered safer to be isolated by a transformer.
56229
Sorry, i am novice in electronics, trying to understand basic fundamental of electronics.  1. How does capacitor conduct current when two plates aren't physically connected.
21800
When electrons flow through a conductor it is subject to resistive loss, which has the unfortunate capability of producing heat from this current, leaving us with less current in the other end of the conductor opposite to the power source.   When current is lost due to heat, what happens to the electron? I mean, what is left of it? I guess heat is caused by friction, but that doesn't mean that the electron is not able to travel all the way through to the load of the conductor, or what?
14142
I'm interested in what kind of energy has electric current ?. For everything I taught in school should have kinetic energy because electrons are on a certain potential within the electric field when the switch is closed then the electrons move and the electric current is "generated" which then should have the kinetic energy. And so I was thinking all the time until I came across this article  which actually tells me that everything I know about the electric current is wrong On the other hand, I wonder if so many books from college ,schools, are spoken in the wrong way It's just a little weird that a huge number of scientists and engineers are actually talking nonsense all the time and so I hope that you can help me clarify my dilemma.  thanks in advance.
41239
So I have been mulling over Ohm's law for hours today. It makes sense to me that the current gets bigger as voltage rises, since the voltage is supplying more electrons and current is the number of electrons flowing. However, I'm confused by the theory that as resistance drops, current increases, even when voltage stays constant. Such as:  $$V/R = I$$ $$\frac{1V}{0.0001 \Omega} = 10,000,000 mA!!$$  That's a big current from such a small voltage!  My mental picture of a current is more electrons flowing. Electrons are supplied by the voltage, right? If we start off with a small voltage, say 1V, but infinitely decrease the resistance, we'll get a bigger and bigger current. How can this be? Isn't current the number of electrons flowing? With fewer electrons (because of less voltage), how can less resistance infinitely increase the current?
18998
Though voltage and current are two interdependent physical quantity, I would like to know what gives more "shock" to a person - Voltage or Current? In simple words, will it cause more "electric - shock" when the voltage is high or Current is more?
124205
What exactly goes into a transformer's VA rating? At a fundamental level it seems that there has to be a limit to what the VA rating can represent.  For example if I draw 2 Amps-RMS from the secondary of a 30VA rated transformer at 15 Vrms this makes sense as the maximum Complex Power I can draw. Still, at a power factor of 1 my maximum current in the transformer would be sqrt(2) * 2 Amps.   But what if my power factor is abysmally low (ie in a DC rectifier) due to harmonic distortion and while I still draw 2A-RMS I have brief current spikes of 15 Amps? Surely the transformer's magnetics couldn't handle these spikes as I'd expect the core would saturate.  My question is what is the practical limit for VA ratings of transformers? Would brief current spikes that reduce to only 2A-RMS in this case be fine? Obviously the secondary/primary copper losses play a part in the rating but how do the magnetics factor in?  I ask this because I am designing a simple bench power supply using a 125VA transformer with a 24Vrms secondary and am trying to figure out how much power I can draw before the current spikes into the inductor are too much for the transformer. I also don't want to have to resort to active PFC as I don't want to risk messing up any HVAC PCB design.  Thank you
11443
Why does a moving (at constant velocity) magnet release more energy in the form of magnetic fields when the number of charges placed near it are increased? Say two current carrying coils $C1$ and $C2$ are in a system in which $C1$ is moving at constant velocity. The magnet fields from $C1$ will reach $C2$ after an interval of time. So at the moment $C1$ releases energy (M.F) it doesn't know about charges surrounding and it can't make predictions of how much energy is to be released at the instant. So it can only give out a fixed amount of energy in M.F.  Let's say it is equal to $M'$. When we add another coil say $C3$ in system, the amount of energy released by C1 is still $M'$. Therefore the total output can't exceed $M'$.  This statement says that you can't get more wireless energy by constant velocity gaining magnet in output even if you use many sets of coils.  But I think that it is false and we can get larger amount of energy as output by using extra coils. C2, C3, ... Cn Explain what is right
28037
If current is the rate of flow of electrons past a point. Let's say a wire is full of electrons, and of course they pretty much are already going the speed of light, minus friction. What would increasing the voltage do?   You can't go faster than the speed of light, and you can't increase the rate of electrons because no more fit in the tube. I am just curious what this would look like. I feel like I am missing a key concept.