 okay so now that we have understood what affects the resistance now we will talk about how resistance affects everything else okay so we will talk about circuit analysis now circuit analysis voltage and current which says that V is equal to I times R what is G? potential difference across the resistance okay V is potential difference across the resistance it is not just any potential difference okay so V is equal to I times R what is I? current current through the resistance so if there is a resistance connected resistance fine and along the direction of resistance potential will decrease or increase? it will decrease so a situation like this if current is flowing like this which will be in high potential this one or this one? from the direction it will decrease okay so these are few basics which you should know so this is how resistance will the things around itself it's a resistance against the flow of current okay so this current is suppose driven by a voltage fine so current should go like this fine so how it actually supports the current so we have deals with only one the distance at a time you cannot analyze right so that the resistance and treat it as if there is single resistance connected there 5, 6 resistance then I will very easily and find out the current right now equivalent resistance fine so basically resistance is so there can be multiple resistance okay tell me how these resistances are connected how these resistances are the series of parallel both what do you mean by both? I mean that is nothing actually combination of series of parallel doesn't mean anything combination of these parallel may mean that some are connected in series and some are parallel for the same resistance so how these two resistances are connected suppose this and this how they are connected so are the series of parallel cases there can be infinite resistance can be connected okay series and parallel are just two special cases so when it comes to special cases okay okay battery source is V okay is it possible for me without this battery knowing about it as in nothing should be sense with a single resistance okay and same way same current happening here and what is happening there you need to connect these two circuits then only you will be able to find a relation between this and that fine so try to connect between what is happening here plus V3 you have connected these two circuits with an equation that is I R2 and this one is R equivalent is R1 plus R2 plus R3 when they are connected in series any doubt on this? a single resistance potential difference here will be equal to potential difference here so V is equal to V you will get that will not fetch anything I2 plus I3 suppose this is I1 this is I2 and that is I3 so this is V by R equivalent it will be V by R1 plus V by R2 plus V by R3 so I can say that 1 by R equivalent is 1 by R1 plus 1 by R2 plus 1 by R3 and if there are more resistance connected in parallel you can just keep on adding you can do some sort of analysis as in 1 by R equivalent is 1 by R1 so R equivalent you can write it as R2 by R1 plus R2 this can be alternate so R equivalent suppose you have 1 million ohms connected and you have to decrease its resistance just connect 1 ohm across 1 million ohm table resistance will become less than 1 unit so equivalent resistance in parallel connection is less than the yeast potential difference at this point and that point then you find these 2 currents basically you define R3 as so then the current flow will be same so that whole equivalent because V is equal to IR so we can find out the potential across that whole thing correct so the equivalent resistance is what this is all number 2 V1 2 is