# Energy is dissipated in the form of heat

I read in the "Lessons in Electric Circuit" book, volume 2: "One might wonder why anyone would bother with such a thing as AC. It is true that in some cases AC holds no practical advantage over DC. In applications where electricity is used to dissipate energy in the form of heat, the polarity or direction of current is irrelevant, so long as there is enough voltage and current to the load to produce the desired heat (power dissipation)."

Why is current irrelevant "In applications where electricity is used to dissipate energy in the form of heat"? What's a good example about this?

Regards,

• The direction of current is irrelevant. – Bort Aug 10 '16 at 15:30
• An example of applications where electricity is used to dissipate energy in the form of heat would be a an electric heater, a soldering iron, an oven, a toaster, etc. – jonk Aug 10 '16 at 15:53
• At least try and quote yourself correctly. – Andy aka Aug 10 '16 at 16:26

It says "the Direction of current is irrelevant", not that the magnitude of the current is irrelevant.

A resistor will heat up to the same extent whether the current flows from left to right, or right to left, or continually changes direction, as with AC.