How Everything Works
How Everything Works How Everything Works

Question 258

Why do north and south poles on magnets change back and forth?
Only electromagnets can change back and forth and then only when they are connected to a supply of alternating current. A permanent magnet, such as that used to hold notes to a refrigerator, has permanent poles that do not change. But an AC powered electromagnet, such as that found in a transformer, does have poles that change back and forth.

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