Is a transformer following ohm's law?

In summary, Ohm's law states that voltage is directly proportional to current. However, in a transformer, if the voltage is increased, the current is actually decreased. This does not mean that the transformer is not obeying Ohm's law, but rather that Ohm's law is applied separately to the primary and secondary circuits of the transformer. A transformer is not a load and therefore cannot be analyzed using Ohm's law in the same way as a resistor.
  • #1
srishankar18
4
0
According to ohm's law voltage is directly proportional to current that is if voltage get increased current also should get increased but in a transformer if voltage get increased current get decreased.

so, Is a transformer is obeying ohm's law or not
 
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  • #2
You are not applying ohms law to the transformer correctly when stated the way you have. If you apply 100 volts to a 10:1 transformer you will end up with 10 volts out. If you put a 10 ohm resistor on the secondary you will have one ampere passing through the resistor. In an ideal transformer the 100 volt source will be sourcing .1 amps. Increase the primary voltage by a factor of 2 and the secondary voltage will increase by the same. The amps in both windings will increase by a factor of 2 as well. Ohms law has not been violated.
 
  • #3
To put it another way, Ohms law is for determining the behavior of electricity through a load (a resistor). A transformer by itself is not a load.

We see people make this mistake a lot (that's 3 times in 3 days) and I don't know why...
 
  • #4
Yep. Remember that Ohm's law only applies for Ohmic devices (which obey Ohm's law and hence named thus).

(Seriously, I'm not trying to be smart or patronising here.)
 
  • #5
You apply Ohms law separately to the primary circuit and to the secondary circuit of a transformer. You do not use Ohms law to learn how the primary induces current in the secondary.
 
  • #6
Thanks

Thanks a lot to every body who had taken care for replying this thread.

I've got some information from your answers.

Thank you ...:smile:
 

Related to Is a transformer following ohm's law?

1. What is the difference between a transformer and ohm's law?

A transformer is a device that is used to change the voltage level of an alternating current, while ohm's law is a mathematical equation that relates voltage, current, and resistance.

2. Can a transformer be used to violate ohm's law?

No, a transformer cannot violate ohm's law because ohm's law is a fundamental law of physics that applies to all electrical circuits.

3. How do transformers and ohm's law relate to each other?

Transformers and ohm's law are related in that transformers operate based on the principles of ohm's law. The voltage and current ratios in a transformer are determined by the ratio of the number of turns in its primary and secondary coils, which is governed by ohm's law.

4. Can ohm's law be used to calculate the output voltage of a transformer?

Yes, ohm's law can be used to calculate the output voltage of a transformer. The equation V2/V1 = N2/N1, where V2 is the output voltage, V1 is the input voltage, N2 is the number of turns in the secondary coil, and N1 is the number of turns in the primary coil, can be derived from ohm's law (V=IR).

5. How does the current change in a transformer according to ohm's law?

The current in a transformer changes according to ohm's law, where the current in the secondary coil is equal to the current in the primary coil multiplied by the ratio of the number of turns in the primary and secondary coils. This is represented by the equation I2/I1 = N1/N2.

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