Vacuum tubes are non-ohmic devices
non ohmic devices are diodes, LED's, Thermistors, LDR(light dependent resistors, cells in series.
the resistant in ohmic devices is constant because it depend on temperature ..and temperature is constant independent of polarity of potential difference...btin non ohmic the tempt increase with voltage which increase due to the heat increase beacue of power dispition....collision of electrons increases find more resistenc for passing so resistence increases
no.....thermistors are not ohmic.
ohmic conductor does obey ohm 's law. non ohmic conductor does not obey ohm's law.
which law follow non ohmic substances
A non-ohmic resistor doesn't have a constant resistance. A ohmic resistor has a constant resistance.
iron,gold
ohmic conductors are those which obey ohm's law
An 'ohmic' resistor is one which obeys Ohm's Law. For Ohm's Law to apply, the resistance of a circuit must be constant over the range of incremental voltages applied to it. If the resistance changes over an incremental range of voltages, then it is said to be 'non-ohmic', and it does not obey Ohm's Law.
ohmic ocnductor is a material which obeys ohm's law: i.e. the voltage and current are directly proportional 2 each other anda non-ohmic ocnductor is a material which doesn't obey ohm's law:)
For Ohm's Law to apply to a conductor, the ratio of voltage to current must remain constant for changes in voltage.If the ratio changes when the applied voltage changes, then Ohm's Law does not apply.It's as simple as that!Conductors or devices to which Ohm's Law applies are termed 'linear' or 'ohmic'; those to which Ohm's Law does not apply are termed 'non-linear' or 'non-ohmic'. There are far more non-linear devices than linear devices, from which we can conclude that Ohm's Law is not an universal law.