Ohms law failed?

Why does Ohm's law break at high frequency (frequency of either the voltage, or current source)?

This is wrong, Ohms law is applicable at every frequency. At high frequency resistors will exhibit inductive and capacitive effects. At high frequency the linearity vanishes. At high frequency the oscillations are more.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Abhay Tiwari
Jul 17, 2015

Due to the distributive nature of the circuit elements the ohms law fails, as ohms law treat the elements as lumped(that can be treated as point form), but at high frequency the distributive nature becomes dominant, and the conductor start acting as waveguide instead of treating it as a simple conductor.

Maunil Chopra
Apr 17, 2019

Ohms law state that V=IR and at high frequencies this is wrong . Because any circuit in practical circumstances(don't use this about or near zero kelvin because then we can't even use classical electrodynamics and have to use quantum electrodynamics) have some finite capacitance and inductance (theoritical it can be zero ) and so we need to solve a second order differential equation instead of a approximate equation of ohms law. The equation tell us that potential drop across some circuit is some constant times charge plus some constant times current ( time derivative of charge) plus some constant times rate of change of current.

If we us q for charge and q* represent time derivative of q, then mathematically our equation is ξ=(q/c)+(rq )+(lq *)( here r= resistance. c=capacitance, l=inductance)

Now we solve this equation for a normal case where q and ξ(potential drop) are sinusoidal functions of time then we can see that at moderate frequency ohm law is nice but at high frequency it breaks down.

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...