00:01
This problem is going to deal with a delta y transformation.
00:05
It's also going to use oms law, of course, and it's going to use the formula that we have for total resistance, either in a series or in a parallel circuit.
00:16
I've redrawn the circuit so that it's a little more clear where the y is going to be.
00:25
So we're going to turn that into a delta.
00:29
And then we'll transform that into a y.
00:33
And eventually we're going to work our way down so that we find v0, the voltage drop across that 6 kilo -oam resistor.
00:43
So for a delta y transformation, what we'll do is over here, i'll go ahead and put in these values for these resistances.
00:55
So i have 6 kilo -ooms.
00:58
I have 18 kilo -ooms and i have 12 kilooms.
01:05
And for each of these corners, a, b, and c, then we have an equivalent resistance over here.
01:13
And to find that resistance, we multiply the two resistors on either side of that corner and then divide by the total of the resistances.
01:23
So for instance, for let's say resistance c, which will be over here at this leg, resistance c is going to be equal to 6, which is r1, times 12, which is r3, and that will be kilo -ooms.
01:43
And that's going to be divided by the sum of the resistances, that's kilowatoms squared, some of the resistances which is 36 kilo -ooms and so resistance c is going to be equal to two kilo -ooms and so we'll do that for the other ones and then we can draw the circuit with a y branch so that two kilo -ooms is over here for our b that is 18 times 12 divided by 36, it gives me 6 kilo -ooms, and then here was 6 times 18 divided by 36, that gives me 3 kilo -ooms, and i have 4 and 6 down here.
02:30
And so for this branch here, my total resistance will be 12 kilo -ooms, and here i'll have 6 kilo -ooms, and then i can combine those because their resistance for parallel is going to be 1 over, 1 over 6 plus 1 over 12.
02:48
And so the resistance of that part of the branch is going to be four kilo -ooms...