- #1
Vibhor
- 971
- 40
This is a snapshot of the diagram in the high school textbook.
and here is the accompanying text
I would like to understand the "minus" signs in
- N1dΦ/dt and - N2dΦ/dt
This is my understanding -
When there is a crest of the sinusoidal voltage i.e top terminal of the input voltage is positive , then due to induced EMF in the primary coil of magnitude N1dΦ/dt , top end of the primary coil is positive and bottom end is negative .Now if we write the Kirchoff's law around the primary circuit then we get the desired equation as given in the text .
Is this reasoning correct ?
But in this case magnetic flux would be anticlockwise around the core , so now an EMF of magnitude N2dΦ/dt would be induced such that top end of secondary coil is negative
and bottom end is positive .
Is this reasoning correct ?
But then why is EMF in secondary coil written
as -N2dΦ/dt and not simply N2dΦ/dt ??
Please help me understand the negative signs in the induced EMF terms .
@ehild , @cnh1995 , @Merlin3189
and here is the accompanying text
I would like to understand the "minus" signs in
- N1dΦ/dt and - N2dΦ/dt
This is my understanding -
When there is a crest of the sinusoidal voltage i.e top terminal of the input voltage is positive , then due to induced EMF in the primary coil of magnitude N1dΦ/dt , top end of the primary coil is positive and bottom end is negative .Now if we write the Kirchoff's law around the primary circuit then we get the desired equation as given in the text .
Is this reasoning correct ?
But in this case magnetic flux would be anticlockwise around the core , so now an EMF of magnitude N2dΦ/dt would be induced such that top end of secondary coil is negative
and bottom end is positive .
Is this reasoning correct ?
But then why is EMF in secondary coil written
as -N2dΦ/dt and not simply N2dΦ/dt ??
Please help me understand the negative signs in the induced EMF terms .
@ehild , @cnh1995 , @Merlin3189
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