# Inductor efficiency

Hey everyone,
I am taking a circuit 1 course in college and was wondering if an inductor is actually efficient. What I mean is that does it produce more current than the current already supplied. I know it keeps the circuit going even after the voltage source is cut, but does that mean that, if I added this inductor, I used less to produce more or is it the same if this inductor wasn't there in the first place?
Thanks

BvU
Homework Helper
I am taking a circuit 1 course in college
So you are aware of the equation that describes the working of an inductor ? Try to formulate your question in terms of the variables in these equations and you will probably be able to answer your own questions.
if I added this inductor, I used less to produce more or is it the same if this inductor wasn't there in the first place?
If you have a specific circuit in mind, draw it in full and do the math ! If I read your question it almost looks as if you missed the word 'passive' in the link.

fight_club_alum
I think from the equation I can say that it depends on the inductor's coefficient itself. Am I correct?

BvU
Homework Helper
it

I have no idea what it is you want me to confirm/deny ...

DaveE
anorlunda
Staff Emeritus
if I added this inductor, I used less to produce more
Everything on Earth, including electric circuits, obeys the conservation of energy. Is that what you are asking about?

fight_club_alum
Everything on Earth, including electric circuits, obeys the conservation of energy. Is that what you are asking about?
I think yes but will there be loss of energy between the conversions that take place magnetic field to current or vice versa?
Thank you

I think yes but will there be loss of energy between the conversions that take place magnetic field to current or vice versa?
Thank you

Not sure its right to look at it being energy conversion between magnetic field and current, the two are intrinsically linked, ie one cannot exist without the other, if you have moving charge, a magnetic field will be created.

So when you look at the equations, then there is no energy loss. However in the real world, current flows through wire that has a non zero resistance, so you have I2R, and most magnetic materials have hysteresis losses, which also remove energy from a magnetic system as the field changes in strength.

fight_club_alum
Baluncore
I think yes but will there be loss of energy between the conversions that take place magnetic field to current or vice versa?
There are, and always will be losses in inductors. Designing low loss inductors can be challenging. A well designed inductor will be warm when it is operating. The temperature of the magnetic core material should be similar to the temperature of the conductive wire. If that is not the case, it indicates the engineer has not balanced the design of the core and of the winding.

1. While current is flowing, the resistance of the winding will generate heat; W = I²R.

2. Whenever the current changes there will be a change in the magnetic field that will diffuse through the core material. That will generate heat losses due to eddy currents that flow in the conductive parts of the core. There may also be minor dielectric losses in the core material binder.

3. Any stray magnetic fields outside the core will propagate away and be lost from the inductor as EMI.

4. If the current transitions are rapid and the particles of core material are thicker than the skin depth in the core material, there will be insufficient time available for the field to diffuse from deep in the core. That deep field will cancel the applied field, which will waste magnetic energy to heat.

Despite the losses, well engineered inductors make very useful components.