Further into Inductors | They're the magnetic analog of capacitors! | Doc Physics
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- Опубликовано: 6 сен 2024
- This will be helpful as we begin to toy with the idea of changes in circuits. There's only so much you can do with steady-state stuff, right?
U dont deserve to be a high school teacher Doc..... U deserve to teach at a university... Your explanation is better than my lecturer's explanation 10 times
Your teaching style is engaging, inspiring, passionate, and well thought out. Thank you.
oh gosh so helpful! you have so much character when you talk it keeps me focused :) thank you doc!
Nice lesson. BTW, since current doesn't like to just stop, when you open the switch abruptly, it will arc and you will get a nice EM pulse that can be heard on an AM radio.
can you please please replace my lecturer ? omg youre so good ! thanks for sharing the knowledge on this !
The first person that i see what know to teach. I m glad to watch yours videos.
WELL U ACTUALLY WROTE THE CORRECT FORMULA OF THE INDUCTANCE IN A SOLENOID(AT 9:30). I GUESS ariaghafari73 WOULD BE CORRECT IF THERE WAS "N" INSTEAD OF "n". U HAVE DEFINED IN THE PREVIOUS VIDEO U HAVE DEFINED """"""n= N/l. DO U REMEMBER THAT DOC. BETTER CHECK IT AGAIN. But as the other videos ur explanation was rocking. THANK DOC FOR THE HELP.........
Oooh, nice. No problem with that at all. However, you must acknowledge the two simultaneous effects of more resistance: not only is the final current smaller, you'll get to 63% of it faster, which defines tau. From a physics perspective, it feels great, since resistance decreases the inductor's ability to prevent its flux changing. A superconducting coil NEVER gets to 63% of its final current (infinity)!
I appreciate your perspective greatly! I hope my in-class students consider it too.
Doc Shuster you are Brilliant!!!
your explanation is easy to understand .. i want to know the relation of inductor and EMF .. 'BACK EMF' ..
I really love your videos,
From Italy 👍🏻
I agree with Mv Dk - I think you were initially correct at 9:30 when you used n instead of N, and defined n as N/l. Please remove that pop up note if you're already correct!
Perfectly explained. 👍👍
I have a question that is not directly related to this video. Ok, so an inductor induces voltage to another inductor/coil. Current in the secondary would produce a magnetic field, right? Wouldn't that induce a smaller amount of EMF into the primary side?
Yep! That, in turn, would induce a current in the second coil. Are you following the directions of all these induced currents? Very often, we find something very complicated happening in physics and we decide carefully how many times we want to pay attention to the accumulated, but weakening effect. In fact, the advanced technique of perturbation theory uses this exact principle to zero in on the most important parts of a problem. Good work.
Hand wavy at 6:49 derivation of potential energy derivation. SOLVE THE DIFFERENTIAL EQUATION LIKE A MAN DOC!!!!!!!!!!!!!!!!
Dillon Berger That's the best advice I've had all week!
WHY YOU SAY SQUUUURED INSTEAD OF SQUARED?!?!
ffs i know. He saw it on a calculator i guess and loved it.. SQR
At 9:30, you asid the inductance of a solenoid is u*n^2*A*L, when it's actually u*n^2*A/L
+ariaghafari73 If L=(𝜇𝑜N^(2)A)/l and n=N/l , then it should be L=𝜇𝑜n^(2)Al? Please point it out if I am wrong :)
i'm confused too..
i support 9797cleo
Hey, great videos. Do you have something about mutual induction?
yes please. mutual inductance.
Good stuff.
Hello, enjoying greatly your videos. Your enthusiasm keeps it fun!
Tough, (at 14:50) shouldn't it be that the current has fallen by 37% at time=tau?
Please reconsider the solution given for opening the switch after a long time (13:00). When the switch is opened, there is no path for inductor current. Put another way, with the switch open, the time constant is zero since the open switch is in series with the resistor. If you don't find this convincing, then consider simulating in SPICE or equivalent.
As long as you are pointing out symmetry, when you derive the energy densities, why not use H instead of B? u = 1/2 mu0 H^2. u = 1/2 eps0 E^2. After all, B is magnetic flux density, and H is magnetic field intensity. E is electric field intensity. Also, you got the inductance of the solenoid right (9:28). Great video.
too good!!! best video ever. Which University are you attending as a professor? I need to apply that
+Sam Shen Thanks for your kind words. I'm a high school teacher.
+Doc Schuster I'm willing to join high school again for all this awesomeness. :D
+Doc Schuster WAW
mu not times epsilon not is c so the energy density of an electric field has an extra c compared to the energy density of a magnetic field. Where c is the speed of light so another hint to how electricity and magnetism are related by the speed of light as Maxwell showed.
Tau being inversely proportional to the resistance is counter-intuitive. Would it make more sense to say that with a larger resistor, you will have a smaller I_final? Mathematically this would be shown as R=Vbatt/I_final ---> Tau= L*I_final/Vbatt
An action of current creates a reaction from the inductor. (similar to
Newton 3 law)
You definately need an outro with a song. The way you are so energetic, a plain ending doesn't seems good. Add probably rap at the end. Jk....I am binge watching all of your videos. Better than Netflix!!!
When you say the current takes a long time to pass through the inductors if we close or open a circuit, how fast is it in our normal seconds? is it few seconds or years or days or what?
Thanks
It depends on the resistance of the coil. Do some more research into "time constants." I have a video on exponential decay that might help...
please explain how t(tau) = L/R.
Is that table made of muskmelon?
if you could not use the lagrange L that'd be great, other than that helpful vid :)
It was supposed to be a fancy i :)
except capacitors hold a charge a lot longer.
what does mew not stand for?
Vacuum permeability constant (mu-naught).
Epsilon-naught is vacuum permittivity constant.
One is for magnetic field, the other for electric.
So it was actually L that looks like a Z, what a plot twist.
Be my physics teacher I will pay u billions
Great series, just stop saying "squr"!
Lucas Morrison squr is the best part!
Lucas Morrison That's my favorite part!
Around 14:xx-ish, you have a real problem once you open up that switch. Your switch is in series with your inductor! You opened a switch that was in series with an inductor that already had current flowing through it! ARGH! So, your analysis is fine, except that your R is not merely the R of the resistor, but the R of that open circuit of the switch (a really big freaking R when the switch is open - ideally around infinity). Thus, your tau is zero seconds, and that current goes away "instantly" (in a exponential decay of course with a tau of zero seconds). Otherwise, you end up with a KCL crisis. If you did this in the lab and were observing the current on an oscilloscope, and if you didn't know better, you might be thinking, "Where is my time constant!?!?!"
Dan Hillman To clarify, the initial current when you open the switch is V/R. But the R used in the time constant is tau = L / (R+Rbig) = 0, since Rbig --> infinity.
scwere
So you’re saying an inductor is like a woman, it doesn’t know what it wants. Lol
Teoretic very,very weeeel!Practic....desastre!!!