Relevance Of Ohms Law

Ohm's Law is fundamental. It isn't going to change, ever. On what basis do you imply its present irrelevancy?

Two that come to mind immediately are voltage drop and fault current.

Two that come to mind immediately are voltage drop and fault current calculations.

Are you trying to say that ohms law is redundant? or you don't know about it and want to know how it can be applied in design?

obviously it has...

offcourse if u say, the load may be inductive or capacitive due to which other factors also become important, but resistance (may it be capacitive or inductive reactance) is always going to be the deciding factor for the current. and once you knw that, u can decide a lot of significant things like- loading, wire rating coupling methods of a circuit.

Ohms law has its own place in electrical engg as the other advanced techniques have.

It is like saying the Newton's laws are irrelevant since they are not applicable to quantum physics.

When you go to very high accuracy calculations (ie like Quantum Physics equiv in Electrical) the Ohm's become approx since the basis

V α I becomes no more correct

Rather V = f(I) now

But in electrical engg on broad lines (like in mech engg on broad) - the machines are designed based on Ohm's law or the macro extension of it taking the L & C into account

Hence the relevancy/ irrelevancy is in the mind of the beholder

Just realised it is a home work questen, this guest or another one have posted the same question in this forum

So bad, it was an interesting topic, but helping in cheating ? sorry

SB, this is not a home work question. In fact I understand Ohms law but I was just wondering how relevant it is today in the design of circuits (Of course it is relevant but I was tyring to figure out How relevant - I hope you understand what I am trying to say)

Thanks for the repsonses

Makmud

If you are not on home works then

The relevancy of ohms law remains the basic, it is relevant as far as design of electrical circuits are concerned on DC side.

On AC side now it is modified in various ways

a) The V = IZ is the basic. and it is as good as ohms law modified, only R is now replaced by Z

b) This law - let us still call Ohm's law is applicable throug-out again repeat on macro scale since even if you have diodes, or any other thing in line which has a constant voltage drop - still the same rule applies (KVL which is basically from the ohm's law)

e) te problem happens on micro scale- when you are working on AC- too many things now are dependent on the phase, the natural frequency of components, the supply frequency etc (just an example is the skin effect, current due to L_C oscillation etc) all these are now going to affect the Ohms Law which is still applicable but now things start getting complicated because too many things are now not only dependent on the basic components but also on the lay out and other things.

This makes us feel as if mr Ohm is outdated since now we do not get an actual value

V = IR or even

V=IZ

but V = f(I,Z,f,...)

I know this makes the matter complicated but it is like this.

If you are talking about electronics the problem is this that we do not talk much about now the currents but rather electron movements- and there it faces much less of R or Z rather it sees the enfs and voltage (i think it is called barrier ? lost the term but hope you got the concept) - at this stage we are at quantum stage and not in macro - since we do not look at massive flow of electrons rather we concentrate on movement of a small bunch - and they are affected in some other manner than what is treated by Ohms Law

Hope it partially satisfies (or confuses I don't know)

PS: Mr Guest, please log in , you know it is free, at least we will know we are talking to somebody who is serious.