when we apply AC Supply to the resistive circuit how does the voltage and current behave in resistive circuit and the most important part is what about the power situation in case of an AC circuit having resistor in this video we are going to discuss all of this in the easiest way possible so if you are interested you need to watch the video [Music] hello everybody and welcome back on the channel now before we start with the today's video If you haven't logged in on our official website that is www.theelectricalguide.n yet then you're missing on a lot of things you're missing on the community features for electrical engineering you are missing on the easiest courses that I'm offering on the electrical machine and also some introductory courses on power system so definitely go and check out login and you will see a lot of good things there now let us talk about AC through resistive circuit now we know about the resistance right resistance simply opposes the flow of electrons now it really doesn't matter what is the magnitude of current whether it's 5 ampere 15 ampere or 500 ampere it really doesn't matter it also doesn't matter that whether the current is alternating in nature or is it constant so anything you that you will pass through the resistor it is simply going to oppose that flow of electrons right and that is the reason why register always follows the Ohm's law now what Ohm's law tells us Ohm's law says voltage is directly proportional to the current provided the resistance is constant so if your resistance is constant then it is pretty much clear that the voltage is directly proportional to the current and that means when current increases the voltage will also increase and similarly if current decreases the voltage will also decrease this is really the easiest thing in case of resistive circuit now with the help of this explanation we can plot the waveforms for current and voltage in case of resistive circuit so let us do that here now first let us plot the alternating current waveform so this is how the current will flow in case of resistive circuit that is the alternating in nature now it is pretty much clear from the explanation that we just saw that when current increases the voltage will increase that means when current is maximum the voltage will also be maximum and that is the reason why if you draw the voltage waveform it will look like this and from this waveform it is pretty much clear that when current is maximum the voltage is also maximum when current is 0 the voltage is also zero and when current reaches the negative Peak voltage follows that voltage at the same times becomes the reaches to the negative Peak and we can say that voltage and current are perfectly in Phase width each other right very clear when current increases voltage also increases because of the Ohm's law and similarly when voltage degree current decreases the voltage will also decrease across the resistor and hence voltage and current are perfectly in Phase with each other in case of resistive circuit right that's that is how the voltage and current behave now let us understand about the power through resistive circuit now before we understand that we need to understand one important concept and that is instantaneous power now let's say for example I want to calculate the power at this particular instance where voltage and current both are maximum now to calculate the instantaneous power at this particular instance what I have to do is I have to Simply multiply the Mac current Max times the voltage Max and that will give me P Max now this power that we will be getting from this is only true for this particular instance where voltage and current both are maximum and this power will not be true for any other instance on the waveform and hence this power is called as instantaneous power because we are measuring the power at a particular instance and hence it is called as instantaneous power now in case of resistive circuit where voltage and current are perfectly in Phase with each other you calculate instantaneous power at any given instance and you will always get a positive power so let's say even if you are you know calculating power when voltage and current are in the positive side you'll get a power as positive so positive multiplied by positive will give us a positive result when voltage and current are 0 the power will also be zero yes it it gets to the zero but it never gets to the negative side it will drop to zero but it will never go to the negative side and similarly when even when voltage and current Act is negative you will get still a positive output because negative multiplied by negative gives us a positive output so you take any instance on this waveform and you will get only positive power and if you draw the waveform for this positive power it will look like this and this is the most important property of a resistive circuit that the power never goes to the negative side it will always be on the positive side yes it drops to the zero but again it get backs to the positive zero when positive again but never to the negative side and this power is also known as active power so the power that remains always on the positive side is what we call as active power and if you are interested in understanding more about active reactive and apparent power then I have a dedicated and a very easy to understand video on that I'll give link for that video down in the description you can check that out clear so that's how the power in case of resistive circuit now there are two important things that you you should remember in case of AC through resistive circuit one in case of resistive circuit voltage and current are perfectly in Phase with each other now what does in phase mean in Phase means voltage and current reaches their positive Peak at the same time they become zero at the same time and they becomes negative or they reach their negative Peak at the same time so that is one the second point that we need to remember is in case of AC through resistive circuit the power always remains positive it never goes to the negative side right so I hope you understood something useful today and if the video was helpful please do like the video and do share it with your friends that's all for this video guys I'll see you in my next one but till then keep watching keep learning foreign [Music]