The equations that were derived from ohm's results do NOT require linearity to function they work just fine in non-linear circuits the only difference being it's not called ohms law if you do, and it's not called 'ohmic resistance' it's called static, chordal, or DC resistance.
ohmic
One entry found.
Main Entry: ohm Pronunciation: \ˈōm\ Function: noun Etymology: Georg Simon Ohm Date: 1867 : the practical meter-kilogram-second unit of electric resistance equal to the resistance of a circuit in which a potential difference of one volt produces a current of one ampere
— ohm·ic \ˈō-mik\ adjective
From Websters. Where does this definition state linearity ? According to Websters, Ohmic is just a adjective of Ohm.
Do you really think they just pull this stuff out of their behind? Surely the definitions are researched at length, and experts are consulted. What use would a dictionary be if it was just sorta kinda but not really, or maybe?Websters is not an authority on electicity and can therefore only offer the simplest
of all possible definitions while words often have more than one definition.
My basic argument is that in a semi conductor material, even though it's resistance depends on the voltage/currents developed across it's material qualifies it as a non-ohmic device that for any given moment in time it still has a very real resistance that would calculate properly for Ohm's Law. I would appreciate any time you could set aside to respond.
if you disagree, you are disagreeing not only with me, but with several universities especially the one
that that was quoted from.
Hi Mike,
Hey you must be online now too
I almost forgot to mention that i got a kick out of some of the jokes stuck in this
thread too, and it's nice to see a little levity along with some serious technical
talk.
Who ever said Universities were never wrong?
Yes, you have a point there, but then you are taking the EXTREMIST
view again just as Sceanwian does all the time. It's not just 1
university, it appears to be ALL of them.
You have to realize that taking the extremist view can ream all logic
out of anything, and does not add to the order of the system (the
system here being the law or rule we want to talk about).
For example, there is such a thing as a straight line in geometry,
but in real life there is no real straight line. Does this mean that i
can never call anything on earth straight? I dont think so!
If i take the extremist view, i would say that there is nothing on
the earth that is straight so the concept of 'straight line' is flawed.
Thus, i would not be able to advance to lines that intersect and
whatever becausei dont believe in a straight line.
It's when we can find a relationship within bounds that we can truely
say something interesting about nature, but without those bounds
there is no reason in the whole of the universe.
Now that the titans have got their semantics all sorted , is this the final verdict?:
1) Everything obeys Voltage = Current * Impedence at every instantaneous point on its operating curve.
2)If the VI curve of any substance is somewhat linear in its practical operating region , then it is said to follow ohms law which is V=IR where R is constant.
3)If the VI curve is not linear , then it is said to be non-ohmic and it does not follow ohms law. But it does still follows E=IZ where Z is not constant.
All we have in our textbook is the definition about of ohms law and V=IR.
I'm not thinking about the grade. All we have in our textbook is the definition about of ohms law and V=IR. I am asking coz i want to know what the true fact is.
I know that impedance is not the same thing as resistance. But a circuit which has a reactive component along with the resistive component will not have a straight graph for VI (i think). Thats why i mentioned Z in the equation. It was to state that E=IZ would work even if the curve was non linear.
But a circuit which has a reactive component along with the resistive component will not have a straight graph for VI (i think).
1. in most homogeneous materials (i.e. no junctions), V = IR and R is constant (at constant temperature)
Obviously you have never run into a robot duck before.I'm a pretty simple guy when you get right down to it. To me it looks like a duck, and quacks like a duck. I'll call it a duck =)
The average Voltage maybe. Like I said the real world is a whole lot more complicated, in real world materials any resistor above absolute zero has thermal noise associated with it. MrAl is being quiet unyielding in his interpretation of Ohm's law but fails to note if you are unyielding in your definition of Ohm's law then not one single material on earth can be proven to be ohmic if you look at it close enough. It's a GENERAL approximation not holy writ handed down from on high. On a quantum level like most macro laws it breaks down completely.
I have been erratic in my statements, however that's because this is all semantic in the first place. The equations that were derived from Ohm's work outside of Ohm's Law, so for expediancy sake I refer to them general has Ohm's law even when not applied to fixed resistors, because say "The equations derived from Ohm's law" is a mouthful.
I'm a pretty simple guy when you get right down to it. To me it looks like a duck, and quacks like a duck. I'll call it a duck =)
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