Hey thanks for watching this video we're going to talk real quickly about parallel circuit resistance. What happens when you take multiple electrical circuits and you run them in parallel with each other, meaning that there's a separate path that goes through each load? When you hear load, some people may not know what that means, but basically a load is the part of an electrical circuit. That does something, so it would be like the windings in a motor or the filament in a light bulb or the coil on a stove or in an oven. So the part that actually creates light heat magnetism.

That is your load and when you run more than one load where they are in parallel with each other, meaning that you're not going in and out of one to the other, like you do in a series circuit, but but you're, connecting each side to the power Supply it affects the resistance of that circuit differently. So let's talk about how that works. So, first off in a series circuit, the loads are connected in a row or end to end and it's you know. We see this in christmas lights uh when you have christmas light bulbs and one goes out the old school christmas lights, then they all go out and that's because the electrons have to actually move through each load and they're very simple.

All you do is, you just add up the resistances, and then that is your total circuit resistance, but in a parallel circuit the voltage is the same across all the loads, so each load gets the same voltage. So, for example, that's why every light in your house has 120 volts because they're all wired in parallel with every other light, the amperage in a parallel circuit is simply added up, so you just take the amperage of each circuit. You add it up. That's the total amperage of whatever you're measuring, but the resistance is a bit more tricky.

It gets tricky to imagine because the total circuit resistance of parallel loads goes down the more loads that you add. For example, if you have one light bulb connected to a power source, the total resistance of the circuit is just the resistance of the bulb, so one bulb circuit resistance is just the resistance of the bulb, and maybe whatever is in the conductors, which is going to Be next to nothing, if you add another bulb in parallel, the resistance of the circuit actually goes down. So if you're, considering you know two bulbs in parallel, it's in one circuit but they're both connected to the power supply. Then the resistance of that total circuit goes down.

So here's how you do that to calculate the resistance of a parallel circuit. You take each individual resistance of each load, each circuit within the parallel circuit that you're measuring and you divide it into not by one. So you divide it into one, so that would be one divided by resistance, not resistance, divided by one. When you do the calculations, you then add up all the resistances that were divided into one and divide the sum into one.

So the formula is going to look something like this. So if you look at this particular illustration that we have here, one divided by rt, which is total resistance, equals 1 divided by 120 plus 1 divided by 45 plus 1 divided by 360.. So, at the end, our total resistance is going to be 0.0331. That's how we do the math at the end.

It's not often that you're going to do this, but the main thing that i want you to think about in terms of ohm's law in terms of watts law is that when we have lower resistance, we have more current lower resistance equals more current. So it stands to reason that if you have multiple parallel circuits and you add up those currents and that equals the total well, then you're going to actually have lower total resistance. The more parallel circuits, you add, the more paths that you give the electrons to flow through the more current you're going to have a lot of people will say: well, electricity takes the path of least resistance. If that were the case, if electricity only took the path of least resistance and not the other paths, then the only circuit on this diagram that would have any current whatsoever would be the 45 ohm circuit, because it's the lowest one, but we see that it actually Takes all paths and the amount of current that flows through each path is proportional to its resistance and the more parallel circuits you have the lower the total circuit resistance, so the lower the resistance, the higher the amps, adding in additional parallel loads increases the amperage in A circuit we see this every day when we notice that compressor, amps and condenser fan amps added together equals total condenser amps.

So that means that those two loads together actually have lower resistance than either of them individually. That can sound counter-intuitive because of how we think about what resistance is, but the reality is. Is that the more current you have the lower circuit resistance you have so that's it. Electricity takes all of the parallel paths and the more parallel paths you have the lower.

The total circuit resistance and again, if you want to know how to do the math, we actually have a article on this hvcr school dot com, slash parallel dash circuit dash resistance. So that's what this video is coming from if you're in school. Hopefully, you found this helpful in the field you're not going to run into this a lot, but just understanding that resistance goes down with more loads can be something that will make things make sense when you're using your own meter a little a little bit in the Field thanks for watching our video, if you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come out, hvac school is Far more than a youtube channel, you can find out more by going to hvacrschool.com, which is our website and hub for all of our content, including tech tips, videos, podcasts and so much more. You can also subscribe to the podcast on any podcast app of your choosing.

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