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ElectroWhat
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I need help understanding the sign of voltages across an inductor.
There is a current source providing current I to a resitor of resistance R in series with an inductor of inductance L, of which the other end is grounded. The voltage at the current source is V1 and the voltage at the inductor/resistor point is V2.
Explain the sign of V2 if the current is ramped up.
I know from Lenz's law that
Emf = - d Bflux / dt = - L dI/dt.
From Lenz's law, if the current is increasing, an Emf will be created in the opposite direction of the current increase. So the Emf will be pointing from ground to the V2 point. So the voltage will be increasing from V2 to ground ... so the voltage is NEGATIVE?
But that doesn't make any sense. Here's what I'm having trouble with:
This would mean the current is not only flowing AGAINST the Emf, but actually increasing against it.
What am I doing wrong?
Homework Statement
There is a current source providing current I to a resitor of resistance R in series with an inductor of inductance L, of which the other end is grounded. The voltage at the current source is V1 and the voltage at the inductor/resistor point is V2.
Explain the sign of V2 if the current is ramped up.
Homework Equations
I know from Lenz's law that
Emf = - d Bflux / dt = - L dI/dt.
The Attempt at a Solution
From Lenz's law, if the current is increasing, an Emf will be created in the opposite direction of the current increase. So the Emf will be pointing from ground to the V2 point. So the voltage will be increasing from V2 to ground ... so the voltage is NEGATIVE?
But that doesn't make any sense. Here's what I'm having trouble with:
This would mean the current is not only flowing AGAINST the Emf, but actually increasing against it.
What am I doing wrong?