But the bulk of what we're working with our loads and switches and then we also have power sources and a power source is always how many points two points. It's never just one point, because there's a lot of confusion that surrounds this whole idea of common and ground and neutral, and all that there's all sorts of confusion that surrounds that, because we aren't thinking rightly about there's two points and there's always two points. There's two design points that we're creating a path between and ground is not one of them. Ground is a safety circuit.

So when we were using a meter and you're checking the ground, your general, that's generally not the best practice other than just a quick shortcut but it, but when you're diagnosing checking the ground isn't the best practice, because ground is never the intended path. I'm gon na say that again, because you guys you're like looking at me a little blank I'd ground is never the intended path. All right! We're gon na get into that a little bit more in a second. But when we're building up a circuit, we're always building between these two points, and so I'm gon na simultaneously this this little section of the class here, I'm gon na simultaneously show you some symbols that are gon na, be really helpful to you and reading diagrams ladder.

Diagrams in schematics and then also talk about building up a circuit and some of the moat and some of the most common mistakes that technicians make when they are building up a circuit. So, first off line and load, it's important to be able to define that, because, when you're building up a circuit, you want to keep things organized and an easy way to keep things organized is to know this wire that I'm looking at right here is it line Or is it load the side of that switch? It's very helpful all right. So now we're gon na build a ladder diagram and when we build a ladder diagram, we really just kind of take lines between these two points and then that way we can make circuit connections in between these two lines, so we're just making we're making different circuits In between these two lines, now in reality do these two lines exist. Well, a breaker panel bus bar is kind of like these two lines.

I mean it actually has some similarity to that, but in reality these could all these wires could all actually come together in one point under a lug they're, not necessarily in a line like this, and that's where some when I see technicians attempting to build it up On the board, they they want to replicate the physical appearance of the of the schematic, and that's not the point. This represents lineside power on one leg, and this represents lineside power on the other leg. Now one question when I want you guys to answer is what makes these two legs different, because they're both 120 volts. So why would an electron want to travel in between these two points? Right, it's alternating current and that's why I that's why I wrote it 120 volts +, / and 120 volts / +, when the one side is positive, the other side is negative, so it's constantly changing back and forth, and so the idea that in a 240 volt Typical residential circuit, like we see in a condenser or in a fan, coil or air, handler the idea that it's going one direction is a misnomer, because it's not it's constantly electrons are constantly moving back and forth.

All we need is the motion of electrons. We don't care which direction they're moving. It doesn't matter to us, but for us to organize our thoughts, we read it like a book. We start on the left and we go to the right.

That's a logical way for us to be able to create circuits, build them up, and so we pretend like this is positive and this is negative in our heads. But the truth is it's not a direct current circuit. There really isn't a positive and a negative. The same thing would be true: if it was a 24 volt circuit, it would make no difference.

So I would I could do 24. I could do 24 volts and then common, but the truth is, is that until we dedicate one side to ground there really is no comment on a transformer. You guys follow that there's no real common. We dedicate a common by grounding it all right, so we're gon na build a circuit, so we're gon na build a simple circuit here.

We're gon na go in to the switch we're going to make this a normally closed switch, which means when you draw it. It's closed. If I draw it closed, that means it's normally closed and you will use the letters NC to describe that closed means that electrons can move through it there's a path normally-closed, you knew that be smart smartypants and we're gon na have a little we're gon na have A little light here, so this is a 240-volt light. You don't see a lot of those, so we got a lightbulb there and this is so.

What is what is this? In the circuit? It's a load right, it's doing work, it's creating light. What is this in? The circuit, this is a switch, and is that and what side of the switch is this line side and what side of the switch is this that's the load side line side is on, because this is the line. This is the load side. Now.

Is this also a line and a 240-volt circuit yeah? It is, but we're always organizing it in a single direction. Every every ladder schematic you're, gon na see is is drawn in that way. It's read from left to right, not because this leg is any less important than this leg or they're they're, both exactly the same 120. Volts opposite phases to just to just highlight quickly what Britton was saying: they're opposite phases, which just means that when you look at a sine wave which is really just a circle on a time line because really what's happening when the power is generated, it's being generated In a circular motion, but when you put that on a time line to show the passage of time going this way, it looks like a wave like this, and so this is one leg.

So we'll call this l1 here, but then l2 is gon na, be the opposite and a lot of us will say so, if you so you know, we'd see 240 volts between about here and here between these two points and a lot of us would say: well, It's always opposite, but that isn't true, because you can see right here at this point ground or neutral, and both legs of power are all identical when it hits at this point, so even 240 volt power is constantly going on completely on and off as well. This is the trickiest part, so we've got lime, switch load, load side of the switch, so we'll call it load side, and then you have the actual load, which is the light bulb. Okay. Now? What do we call this here this this? After and a 240 volt circuit, we call it L 2, that's all we call it, but if this were a 24 volt circuit.

So let's, let's, let's change this here. We would call it, we would say 24 volts and we would call this common. You know what we would call it if it was a 120 volt circuit, we'd call it neutral. So if this is 120 volts, we'd call it neutral now what makes neutral different than common anybody know on a 24 volt circuit, what's interesting, a 24 volt circuit common and 120 volt circuit neutral they have a common, usually does two common is a more generic term.

So common you'll see common used in all sorts of different applications. Perfect example is this run capacitor here? Did anyone know the three terminals on this on this run capacitor? What are they yep common herm and fan right? There's two capacitors in this: in this capacitor a fan cap and a compressor, capacitor, a larger and smaller and common is the common point between the two. So we say common in electricity. All we're saying is is a common point.

That's all it means it doesn't mean ground, it doesn't mean the same as neutral just means a common point, and so you can get confused really easily, for example, in a compressor circuit, the common side of the capacitor hooks to the opposite leg of incoming power from The common terminal on the compressor itself, you see technicians, make this mistake all the time where they hook see because they see see here and they see see on the compressor. So they hook the two together. But that's not that's not correct, see, that's the opposite of that because see on the compressor is the point where the two windings come together and see on the capacitors, the point where the two capacitors come together, but as far as electrically speaking they're, not similar they're On opposite sides of the circuit, so you have to be really careful with the term common common means a lot of different things. When you hear it when you say it just make sure you know what you're saying cuz it doesn't mean ground and doesn't mean neutral.

Alright, when we say neutral, we are talking about a specific thing: we're talking about a circuit that operates AAPIs on the other side of the load, from line on a 120 volt circuit.