00:01
Let's say we have the following circuit.
00:03
We have voltage source on the left and right.
00:06
We have a 77 .2 milliamp current on the main branch, which you'll see on the upper left here.
00:12
And we have three resistors in parallel.
00:14
We have r1, r2, and r3.
00:17
Our value of r1 is 120 ohms, r2, 220, r3, 330.
00:23
And the voltage on the right side is 4 .95 volts.
00:27
And let's say that we wanted to find the equivalent resistance of these.
00:33
Because all of these resistors are in parallel, the way that you combine resistors in a parallel is that you add the reciprocals.
00:44
So 1 over the total resistance equals 1 over r1, which is 120, plus 1 over r2, which is 220, plus 1 over r3, which is 330.
01:01
Okay? so the best way to add these is by using a calculator.
01:08
I think by using, if you did it by hand, you'd have to find a common denominator.
01:15
And these numbers are like pretty large.
01:18
So like, so like that way would be a little inefficient.
01:22
So if we add all these up, this is going to give us 7 over 440.
01:27
And of course, if we take the reciprocal of both sides, that means our total resistance is 440 over 7.
01:38
And if we divide those, we have 440 over 7...