- #1
hylian_loach
- 2
- 0
I had trouble with transformers and ohm's law, and discussing it with friends, I got this out of them:
I feel like I need to ask because I have (numerous times) accidentally used induced EMF in the formula V=IR, and therefore, end up with a different resistance in the primary and secondary coils, which is, obviously strange.
My teacher claimed that the resistance in the wire does change between the primary and secondary, and I did not feel the need to argue that such a magnitude in change in resistance was impossible.
So, is the above quote true? Because although this may not be examinable, it is very confusing, and correcting any errors would help clear this up! Thanks in advance.
In the formula V=IR, the V represents the potential difference (aka. Voltage Drop).
However, in the formula regarding transformers P=VI, the V represents the induced emf, while in the formula regarding power dissipation in wires P=IV, the V represents the voltage drop between two points
When increasing the voltage to reduce energy loss, the current decreases and therefore the potential difference between the first transformer and the next is much smaller. This leads to a larger voltage at the second transformer, which means less energy has been lost.
I feel like I need to ask because I have (numerous times) accidentally used induced EMF in the formula V=IR, and therefore, end up with a different resistance in the primary and secondary coils, which is, obviously strange.
My teacher claimed that the resistance in the wire does change between the primary and secondary, and I did not feel the need to argue that such a magnitude in change in resistance was impossible.
So, is the above quote true? Because although this may not be examinable, it is very confusing, and correcting any errors would help clear this up! Thanks in advance.