 Okay, so what I'm going to do today, this is going to be a quick one because this concept doesn't have to be that hard and I don't have a lot of time. So it's kind of two and so here's the deal. Today we're talking about adding voltage sources. So I'm talking about DC specifically. We're talking about adding DC voltage sources in series and in parallel. So what you're going to want to do is you're going to want to sit down, grab some paper and if you have a clicky pen, get one of these pens. You see all the different, it's focusing on my face, sorry. Woo, different colors there. That's going to help you out. I get my students to do this all the time. Just having those different colors makes a difference. So go ahead, I'll wait. I'm just going to have a coffee here while you go and get yourself a clicky pen. Okay, I'm assuming you're back and you've got your clicky pen. But what we're going to do is this. When we have voltage sources in series, it's pretty basic. Let's take a look at, I'm going to get into the whiteboard again here. Okay, so let's take a look at our whiteboard. So I've got, there's, say I've got two batteries here. Let's say that each battery is six volts. So I've got two six-volt batteries in series. Now this is so important and please get a little closer here. Right in your polarities, it is so important that getting into the habit of drawing your polarities into every circuit you possibly can is going to help you out. It's going to help you out in DC and it will help you out in AC. What? How can it help you out in AC? That doesn't make any sense. AC is going back and forth, back and forth. Trust me, it will. We'll talk about instantaneous polarity when we get to that. Let's just focus at the task at hand. So in this point here, let's put our polarities in. Whenever I have this big line and this little line, the big line stands for positive. So I have positive there. The little line stands for negative. Again, big line is positive, little line is negative. So I've got those two in series now. I've got a six-volt battery that is going to go in series with another six-volt battery. So what I do with this is, okay, let's say if I put a voltmeter across it and let me show you what I mean by this. So I'm going to put this voltmeter. So I've got a voltmeter here reading from this point to this point. What I want to do is figure out what the voltage is. Now you, I'm sure you're looking at this, you're saying, why am I watching this video? It's so basic. It's obviously 12 volts, but I just want to get into how to calculate this out. Cause what if I started throwing a bunch of other batteries in there and then some were flipped around? We're going to do that, don't worry. So what I do with this is I always start, and I tell my students this, I start at one lead and I try to get to the other lead. And that is what's going to, my voltmeter is going to read. It rhymed, lead, lead, read. So I'm starting here and I'm going to take a drive. So I come along here, I start at this side, a drive over to here. You see, I see a positive first. I'm picking up six friends. I stop, I see another positive. I'm picking up six friends. By the time I get to the other side, I've got 12 friends in total. If you want to add this in as a, as like adding it right down the numbers. And this is why I would suggest getting the clicky pen. I'm going to say, okay, I add six volts and then I add six volts together. I get positive 12 volts. So please watch now, because this is going to make a big difference when we don't write in the polarities, we can easily make mistakes. Watch this. I'm just going to get rid of all this. So let's cut this out. So delete all that. And I'm going to draw in a bunch of batteries and there's going to be more than two. Okay, so I've got a bunch of batteries and they're all flipped around. This gets a little more tricky, but it doesn't have to be. So next up, okay, let's say that these batteries, again, these are six volt batteries. So I'm just going to draw that in here, trust me. It helps to get everything drawn in. So six volts, six volts, six volts, six volts, six volts. Next I'm going to put in my polarities because I've got to. So positive, negative, positive, negative, positive, negative. Oh, snap, negative, positive, negative, positive. Please watch for that. And first off, don't worry about the colors I chose. I'm picking arbitrary colors. It's not like you don't use polarity has to be blue because you noticed in the last example, it wasn't, don't worry about that. So but watch for this little part, this part here. You see where I went from positive to negative, but then I have a negative lead. Make sure you identify that properly right there, negative. That's going to make a huge difference, okay? Next up, let's say I want to read the voltmeter. I'm going to place a voltmeter. We'll make it easy right off the hop. Voltmeter, I'm going to read from this side to this side. All right, so again, we want to go for our drive. I'm going to pick up six friends. Pick up six friends, pick up six friends. Let's identify that by drawing it out. I'm going to pick up six friends. I'm going to pick up six friends. I'm going to pick up six friends. So that's that taken to account. I'm still driving, then I see this negative. I'm going to drop off six friends, draw this out. I'm going to drop off another six friends. Drop off six friends, drop off six friends. And that gets us a total of 18, because this is going to be six plus six plus six plus six is 18, and this is going to be minus 12. So we end up with six volts in total. So again, you can see why it's important to have those polarities written in there. Draw this stuff out. Even if it's given to you, just go ahead and draw it out again. It's going to make a difference. It's going to make a huge difference. So that's all you have to do when you're dealing with these series circuits. You get the polarities in there and you're going to be fine. The thing with flipping this and turning it into a parallel circuit, let me just show you, it's super easy at this point. Let me just cut this stuff out again. Cut it out, delete out of there. Now I'm going to put a bunch in parallel. That's not, not even go a bunch. Let's go this one is in parallel with this one. Let's get that line down there. Again, let's say that there's six volts each. So I've got, this is six volts. This is six volts. We have to remember Kirchoff's law of voltages in parallel. Voltage in parallel stays the same. So in this case here, six volts, six volts. If I measured this as a volt meter, let's put this in as a volt meter here, there and there, I'm going to measure six volts, right? So why even do this? Like what's the point of doing this? Well, remember that voltage stays the same in a parallel circuit. What does current do? It's not a rhetorical question. I'm waiting for your answer. Yes, you, I hear you, Mike. You're right. Current adds. So let's say that this battery here has a capacity of, I don't know, let's just give it an average. Let's say it's got 10 amps capacity. And this one also has 10 amps capacity. Well, if we did this, we have these little nodes here. We know that we're getting six volts out of there. But with just one battery, we're only going to be able to give 10 amps of capacity. But by putting these in parallel, we're giving it 20 amps of capacity, right? 10 plus 10 gives us 20, which gives us more power. Now, I'm going to, where would you use this? A great example. If you haven't watched Breaking Bad, I feel sorry for your son. You got 99 problems in watching Breaking Bad ain't one. You got to watch it because there's a scene in it. I'm going to spoil alert. There's a scene where they're making an electromagnet. I'm not going to tell you why. But in order to get this electromagnet even stronger, Walter and the junkyard guy and Jesse talk about taking the batteries and putting them in parallel in series. Series adds the voltage, parallel gives you more juice. More juice means more flux lines, more flux lines means more magnetism. That's a whole other video for another time. In fact, you probably already have one done. Make sure you jump into the Electric Academy and check out the magnetism videos. They're awesome. And so that's why we put these things in parallel. So just to recap, in series, make sure you write your polarities in. In parallel, you want to make sure that you're going to add your currents. Now what would happen if you had different voltages on different batteries? I'm not going to get into that now. In fact, I cover that when I talk about paralleling transformers. There's a great little thing. Check out paralleling single phase transformers. I talk about that. It's not good. Just a spoiler alert. So you always want to make sure you've got the same voltages in your parallel and your sources. That's all I got for this week. Next week coming at you, I'm going to actually try to get this done. Hold me to it. I'm going to do a house calculation. Also, we're coming up on a course that I've developed with the British Columbia Institute of Technology. Another individual there, Aaron Lee, and I've developed a course on basic math for electricians. It's a 10 week course, self-paced, asynchronous, super cool sounding asynchronous means learn at your own pace, but you have access to people like me and Aaron to help you through. So if you're struggling at all with any kind of the mathematic principles, and just I'll make sure there's a link to it down in the description so you can see exactly what the course is about. Have a great week, everybody. See you next week. Stay classy.