# Polarity of coils on different legs of square core?

Discussion in 'General Electronics Chat' started by electronice123, Jun 1, 2012.

1. ### electronice123 Thread Starter Senior Member

Oct 10, 2008
309
0
If 2 coils (placed on a square coil and wound in the same direction) are on opposite legs and the coils are pulsed with a square wave will the polarity of each coil be the same?

See attachment, is it option 1 or option 2.

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Last edited: Jun 1, 2012
2. ### PaulEE Member

Dec 23, 2011
423
32
I believe option #2 is correct. Here is my reasoning...

Along with your electrical circuit (the coils on either side of the core), there is also a magnetic circuit here - the core. When current is run through the first coil, "+" to "-", the magnetic flux generated in the core, according to the right-hand rule, flows downward during the positive pulse.

If you continue through the square loop, you'll end up going upward through the coil on the right-hand side of the core - which is the opposite case as compared with the other side. Because the magnetic flux is in the opposite direction, so is the current, and so would be the equivalent voltage.