Lec 18 | MIT 8.02 Electricity and Magnetism, Spring 2002

Displacement Current (Difficult Concept)
Synchronous Motors
Induction Motors
Secret Top, How does it work?

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[landin048]

What a great instructor. He has a passion for his work, and a genuine interest in teaching young adults and sharing his knowledge. Wonderful man.

[evilelton]

I'd be failing E&M at umich if it wasn't for this guy, hahaha

[rknaik76]

The students must be lucky .. such a great professor .. I studied my engineering in electrical but working in entirely different area now ... but still I see these lectures and clearing my concepts .. he is a great teacher ..

[lucaspepa]

amazing!

[chrisconwaypeters]

delightful speaker to listen to, well done

[chsor4]

Around 47:00.. I'm really going to make such a thing!

[digicho]

The top works like Adams motor. Switching off current to coil causes reverse of voltage in coil so magnetic poles in coil reverse.

[mdinka]

I guess he must have made a mistake @10:29 in saying that there is no electric flux PHI = Int(E,dA) through the open circular plane at P1. What he probably meant was that the time derivative of that flux equals to zero (dPHI/dt ), hence there is no contribution of the Maxwell displacement current i.e. dPHI/dt to B at P1. So for any location outside the capacitor the "enhanced" Ampere law yields the same results as the "older" version, but it shines for locations within the capacitor.

[brahim121985brahim]

Wonderful man

[mdinka]

@mdinka sorry I meant 'referring to @10:29'

[mdinka]

referring to @12:29 why isnt there a flux going through the surface. There's certainly a E field (otherwise there wouldnt be a current) and dA is parallel to E, so the integral @07:35 shouldnt vanish.