Whats reverse electromagnetic force?

[Cookie_1993]

hi

can you please tell me what is reverse electromagnetic force?

thankz!

 

[berkeman]

I believe that you are referring to "back EMF" that is generated in a coil or transformer.

http://en.wikipedia.org/wiki/Transformer

When you put an AC voltage across the primary of a transformer, that generates an AC (lagging) current in the primary. That AC current generates an AC magnetic flux, which couples to the secondary coil. That changing flux induces a current in the secondary coil, which generates its own flux in the core, and that secondary flux opposes the primary flux. So any current flowing in the secondary causes a reduction of input impedance in the primary (the so-called Back EMF, or reverse voltage due to the reflected load impedance).

Does that help?

 

[Cookie_1993]

ya that helps!
thankz!