When can you not use ohms law?

The standard answer is that you cannot apply Ohm’s law if the component’s resistance is not fixed over its entire range of operating voltages and currents, or in other words, the component is not ‘ohmic’.

What does not follow ohms law?

Many electrical devices have I-V characteristics that vary in a non linear fashion. Such devices are termed non-linear and do not obey Ohm’s law. Examples include filament lamps, diodes and thermistors. The resistance of a non ohmic device may vary with time.

Is ohms law applicable to non linear devices?

Ohm’s law is also not applicable to non – linear elements. Non-linear elements are those which do not have current exactly proportional to the applied voltage that means the resistance value of those elements changes for different values of voltage and current.

Is ohms law valid in AC circuits?

Ohm’s law holds for circuits containing only resistive elements (no capacitances or inductances) for all forms of driving voltage or current, regardless of whether the driving voltage or current is constant (DC) or time-varying such as AC. At any instant of time Ohm’s law is valid for such circuits.

Is Ohm’s law applicable to high current?

Ohm’s law is not applicable at very low and very high temperature.

Why is Ohms Law not valid for non-linear circuits?

Because Ohm’s law defines a linear relationship between voltage, it breaks down in any device that exhibits non-constant transconductance. This means that the current in the circuit element in question is no longer directly proportional to the voltage used to drive the circuit element.

Why is ohms law not applicable to non-linear circuits?

Why is Ohm’s law not applicable to vacuum tubes?

While a vacuum tube shows change in conductance with change in temperature, and thus, change in resistivity. Thus, a vacuum tube is a non-linear circuit. Therefore, Ohm’s law is not obeyed by vacuum tubes.