 In this video what we're going to do is we are going to determine what the volt drop will be across this break in the line. In a previous video we talked about how to determine the voltage across the break in the neutral but this time we're going to switch things up a bit and we're going to break one of the lines here. Now it's a very similar process we're going to walk through it step-by-step so don't worry but it's all about redrawing this circuit and determining what full drops are across all these resistors and then we're going to hop in a car and take a drive and drop guys off and pick guys up. So let's take a step here. Now this guy here we have this line broken which basically means that this battery is ineffective at this point. So let's redraw the circuit. Let's get rid of this battery and start redrawing the circuit so we can start dealing with things that we know. There we go. It looks a little better. We got rid of that battery. So now we're dealing with ourselves a parallel circuit. Now let's take a quick look at this. I've got a 120 volt battery here. Current is going to flow across this 5 ohm resistor which means that this 5 ohm resistor will see 120 volts. That circuit remains unbroken. However when I look over on these three guys I have a path where I can go through the 3 ohm resistor and down through the 10 and back to my positive. At the same time I can also go through the 2 ohm resistor and through the 10 and back to my positive terminal. So let's redraw this so it looks a little more easier to deal with. Okay here we are. There's the circuit that we had before. Put it off in the corner here and now we're going to redraw it. So this guy here this 5 ohm resistor for 120. There it is. 5 ohm resistance of 120. The 3 ohms going with the 10 is right here the 3 ohms going with the 10 but then also at the same time we have the 2 ohms which also is in series with that 10. So these two the 3 and the 2 are in parallel with each other but both of them are in series with the 10 ohm resistor. So let's put it off in the corner here. Here we go and what we're going to do is we've got this guy we're going to basically ignore because nothing happened to him. 120 volts is 120 volts he's happy nothing changed with this guy. However these guys here things got a little funky. So what we're going to do is we're going to focus on this branch. I have a 3 ohm resistor and a 2 ohm resistor in parallel with each other in series with the 10 ohm resistor. Let's crush these two guys together and turn them into one resistor. Sorry what I meant to say was we'll get into one branch. So what I've done here is I've taken these guys here and I've turned it into one branch. The 3 ohm resistor and the 2 ohm resistor in parallel in series with the 10 ohm resistor. Now we're going to crush the 3 ohm resistor and the 2 ohm resistor and see what happens with that. 1 over 3 plus 1 over 2 gives me 1 over 1.2 ohms. These two guys here squished together that guy gives me 1.2 ohms. Again in series with the 10 ohm resistor. So now we're going to add the 1.2 ohms with the 10 ohms to get a total branch resistance of 11.2 ohms. And what we're going to do here is we've got 120 volts and 11.2 ohms on this branch here. 120 divided by 11.2 ohms is going to give me the branch circuit current because then we're going to start working our way back just like we do in every other combination series parallel circuit. Let's do that. 120 volts divided by 11.2 ohms gives us a current of 10.7 amps. So we know that we now have 10.7 amps flowing through this branch. 10.7 amps times this resistance will give us this voltage. 10.7 amps times 10 ohms here will give us this voltage. That works out to be 12.84 volts across the 1.2 ohms resistor and 107 volts across the 10 ohm resistor. Now remember this 1.2 ohms here this guy is actually these two guys crushed together. When voltages are in parallel what happens they are the same. 12.84 volts means that this guy will have 12.84 volts and this guy will have 12.84 volts and we've already determined that this resistor here it has 107 volts. So now that we've got these guys all lined up we can start putting them back into the circuit that we had before. This resistor is 12.84 this resistor is 12.84 this resistor is 107 volts this guy here nothing happened to him remember he was happy he's 120 volts. You're starting to see my process here we are stretching it back out so we're starting to put these voltages where they belong and we're getting close to the original circuit that we had. Both these voltages are 12.84 volts because they're in parallel this guy is 107 volts this is 120 volts let's put all those voltages over onto that guy there. Okay we've got all the voltages moved over there the only thing we have to do now is add that battery back in and we can start determining what the volt drop will be across that break. Alright here we go stretched it all the way back out we have 107 volts on the 10 ohm resistor 120 ohms sorry 120 volts on the 5 ohm resistor 12.84 volts on the 3 ohm we're getting close to the end here. Now the key to determining the volt drop across this break here is to figure out what the actual polarity across all these loads is going to be the negative to positive. Alright so here if I look at this guy I've got the current flowing this way negative to positive so this is going to be negative this is going to be positive. Now back when this line was fine this was going to be negative and positive this was going to be negative and positive. However here's the trick with this one watch for this this line is broken we no longer have this battery current is no longer flowing from this point to this point current is going to flow from this point through there down through here and back or through here up through there down and back the polarity across these two guys has changed it's become opposite of what it was before so now we have a negative and a positive on here and now we have a negative and a positive negative and a positive negative and a positive. Let's get those polarities drawn in because that is so very very important when we're determining what this volt drop is. Okay I've got the polarities drawn in here again flowing from negative to positive then flowing from negative to positive and negative to positive at the same time negative to positive through negative to positive. Now we've got enough information that we could determine the volt drop across this break here so let's figure that out I'm going to start on whenever we determine the volt drop across a break we start on one side of the break and we try to get ourselves to the other side of the break so let's start right here I'm going to start just a few ways we can go about it let's start the easy way first I'm kind of feeling lazy right now so let's go with the quickest route possible I go here and I drop 120 volts I say a drop because this is a negative terminal this is a positive terminal so I drop off or I have negative 120 volts I go this way and I have negative 12.84 volts so by the time I go from this point to this point I have negative 132.84 volts across this break here so that's one way to go now we can take the long road the scenic route I drop off 120 volts then I drop off another 120 volts so I've now dropped off 240 volts I go ticker ticker ticker ticker ticker ticker and you see I've got a positive here so so far I've dropped off 240 volts but now I'm going to pick up 107 volts and I drive all the way to there and I end up with 133 which is basically as close almost exactly the same as 132.84 it's just all in the rounding so again I've dropped off 120 I drop off 120 I move along there but I pick up because of this positive I pick up 107 and I get 133 if I took the short route I drop off 120 and I drop off three sorry 12.84 close enough to 133 that is how we determine our volt drop across the break it doesn't need to be that difficult so remember all you have to do is figure out break this guy down this whole thing down into a different circuit redraw it out figure out your volt drops across each of them then like I said polarity is key determine your polarities and then just go for your drive you drop off you drop off you drop off you drop off you pick up and it all is because I've got those polarities drawn in that I can see how that works that is how you determine the volt drop across a break in a 3-wire circuit