The circuit of the induction coil

[Aya Elsayed]

When we turn the circuit off . There will be an induced emf through the coil due to the changing magnetic field of the AC . Therefore V=-L . DI/Dt
So when the current is zero then the emf has a maximum value . And what about the emf of the source itself ? It's equal to the induced emf? If It has the same value and an opposite direction whey they don't cancel each other out ?

 

[kuruman]

When we turn the circuit off.

What circuit? Can you be more specific and describe it, even better can you post it as a figure?

 

[Aya Elsayed]

What circuit? Can you be more specific and describe it, even better can you post it as a figure?. QUOTE]
The circuit that have an AC source and an induction coil . I mean when we close the circuit why the voltemeter detect a voltage between the coil"induced emf" if the the emf of the source has the same value and in an opposite direction?

 

[kuruman]

OK, I see. The voltmeter cannot detect an instantaneous voltage, which is what you are talking about. You will get a better picture of the instantaneous voltage if you connect an oscilloscope across the induction coil.

 

[Aya Elsayed]

OK, I see. The voltmeter cannot detect an instantaneous voltage, which is what you are talking about. You will get a better picture of the instantaneous voltage if you connect an oscilloscope across the induction coil.

I got it ... So It only detects the voltage between the coil .
So what I said about the sum of the voltages is right ?

 

[kuruman]

According to the Kirchhoff rule, the sum of the voltages around the closed circuit is zero at any time. That is always the case.