00:01
Okay, so for this problem, we know that at time equals zero, we have a certain potential difference applied to a coil of these particular qualities.
00:12
Even though it's a single coil with a certain resistance and inductance, we can treat this as a resistor and inductor in series.
00:23
Maybe the strongest argument is that they both have the same current.
00:28
And so there's two sources of potential difference.
00:31
So kierkov's equation would look like the same as if it were an rl circuit.
00:37
And so or your standard like rl circuit where the rl are in series.
00:44
So yeah, from there on out, it's not too different from problems you've probably seen.
00:50
So let's go ahead and write out the given.
00:52
So the voltage is 45 volts.
00:56
And the inductance is 50 millie henries, and the resistance is 180 oms, and the time is 1 .2 milliseconds, and then our goal is to get d -i -d -t.
01:28
So i is going to be your v over r, 1 -1 minus.
01:33
E to the minus t over tau.
01:35
I've written that so many times...