Question
Sun July 15, 2012 By:

how do we know whether we get ac supply at homes and why ac current is alternating.how is ac current produced so that it is always alternating.from what source ac current is produced

Expert Reply
Mon July 16, 2012
Ac current is made by a usual generator without any carbon brushes but with slip rings. The detailed design and working can be reffered from any good book on electrical engineering.
It produces alternatingcurrent because the coils are not disconnected after every quarter rotation.
You can check if ac current is transmitted to our homes by using a normall dc galvanometer which dont work on ac current.
Also ac current cannot be used to perform some experiments like electrolysis, etc.
Also one drastic way to check is we dont feel the sensation of electric current on touching a live and nuetral wire in dc but we do in ac.
In dc only burning sensation is felt. However this way of checking should never be used do to obvious reasons of danger. its just a fact. The reason behind is a bit complicated for the current standard.
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