Why transformer not obey ohms law?

Answer 1

A: Ohms law apply to any and to all components if there is current flowing.

Answer

For Ohm's Law to apply, the ratio of voltage to current must remain constant for variations in voltage. This is only true for a limited range of conductors and devices which are termed 'linear' or 'ohmic'. If the ratio of voltage to current changes for variations in voltage, then the conductor or device is 'non-linear' or 'non-ohmic', and Ohm's Law does NOT apply. An example of a non-ohmic conductor is tungsten (e.g. a lamp filament) and an example of a non-linear device is a diode -there are many more.

As to whether a transformer obeys Ohm's Law, the answer is not straightforward. When the transformer is not supplying a load, the primary current is determined by the voltage and impedance of the primary windings and, say, doubling the voltage will double the primary current -so you could say that it is obeying Ohm's Law. However, when the transformer is supplying load, the primary current is determined by the secondary current and not just by variations in the supply voltage, so is clearly not obeying Ohm's Law.

Answer 2

Ohm's law gives a relation between Voltage, Current, and Resistance of circuit. Namely, V=IR, or

Voltage = Current x Resistance

Note that this equation states that when Voltage goes up, current goes up.

A transformer is used to change the voltage of an AC circuit - a 1:10 transformer increases the voltage to 10x its old value, while a 10:1 transformer decreases it to 1/10th its old value.

Answer 3

Transformers, like any other electrical component, does "obey" ohm's law, i.e., can be described using the usual combination of current, voltage and resistance, as long as you realize there are at least two circuits (primary and secondary).

Answer

For Ohm's Law to apply, the ratio of voltage to current must remain constant for variations in voltage. This is only true for a limited range of conductors and devices which are termed 'linear' or 'ohmic'. If the ratio of voltage to current changes for variations in voltage, then the conductor or device is 'non-linear' or 'non-ohmic', and Ohm's Law does NOT apply. An example of a non-ohmic conductor is tungsten (e.g. a lamp filament) and an example of a non-linear device is a diode -there are many more.

As to whether a transformer obeys Ohm's Law, the answer is not straightforward. When the transformer is not supplying a load, the primary current is determined by the voltage and impedance of the primary windings and, say, doubling the voltage will double the primary current -so you could say that it is obeying Ohm's Law. However, when the transformer is supplying load, the primary current is determined by the secondary current and not just by variations in the supply voltage, so is clearly not obeying Ohm's Law.

Read more: Does_ohms_law_apply_on_transformer