Question

Name few things which doesn't Obey Ohm's law?

Answer 1

any device which do contain an inductor...that will not follow ohm law as it ohm law is valid only when current is const and in an inductor voltage changes by Ldi/dt so cureent changes

Answer 2

Most electronic phenomena follows Ohm's law, even "negative resistance" oscillation. With AC all things must be considered complex impedances phase angles etc. It is mostly people who don't apply Ohm's law properly.

Answer 3

A diode, for instance.

Answer 4

When the conductor, which you are interested in, is too much cold or hot then the OHM' s law is invalid.

Answer 5

Yeah I know that Ohm's law depend's upon the conductors temperature but I wanna know the example of few real life usage things which doesn't obey's Ohm's law

Answer 6

Actually few things are like Electric Heaters and Incandescent Bulb etc.......

Answer 7

copper wire

Answer 8

Just because a heating element measures a relative low resistance when it is cold, and as current heats up the element increasing the resistance, does not invalidate Ohm's law. George Simon Ohm knew what he was talking and writing about, you just need to know how to apply it to RF, varying temperature, negative dynamic resistance etc. I have had experience with a lot of devices, klystrons, dynatrons, magnetrons, amplitrons, Hall effect devices, parametric amplifiers etc, and unless there has been some recent developments (I have been retired since 1994) all were compliant with Ohm's law. It is true, that my career centered in the radar area, and just maybe there is some device in the "twilight zone" that does not, I'm just not aware of it.

Answer 9

True, even diodes can act as an oscillator in their "negative resistance" portion of their operating curve. However, that doesn't mean that they don't comply with Ohm's law.

Answer 10

Technically nothing obeys Ohm's law. Like everything in physics, it's a mathematical model that closely approximates what we can observe. For instance, it might be that if you get down to the quantum level, Ohm's law is pretty meaningless even though when you zoom out, it might be a pretty good description of the exact same system.

Answer 11

Although that might not be completely fair to say that it's just "matching" our observations. Ohm's law can be derived from Maxwell's equations through several approximations and simplifications, and those describe practically all electrical and magnetic phenomenon. So there's definitely some level of "truth" there.