Originally Posted by **kapital** What does it mean the therm "voltage" in electric circuit?
I know the definition, but I still can not understand anything rely.
I know also that this is the difference in electric potentials, but every point in circle should have a different voltage. And that does not make sense.
(since there is r in the formula for potential, and every point of the circuit have different r from voltage source).
And, how can happens that voltage can drops? |

First of all the term "voltage" is not, in my opinion, a good word to use. I prefer the more correct term "potential drop."

In any event the term voltage is commonly used and unambiguous at least. You have a voltage in any place that there is an electric field. It is one way of representing the energy (gained or lost) of a charged particle in an electric field.

The potential difference across a perfect conductor is zero. That means the charged particles traveling along them neither gain nor lose energy. If the current flows into an insulator (or a material that is not a perfect conductor), aka a resistor, the potential "drops" across the resistor. This is due to the fact that the charges cannot flow freely through the resistor. Some energy is lost and the charged particles lose some energy. This lost energy usually goes into effects such as heating the resistor. The lost energy is represented by the loss of voltage (ie a potential difference) across the resistor.

I'm not sure what you mean by "...but every point in circle should have a different voltage. And that does not make sense. (since there is r in the formula for potential, and every point of the circuit have different r from voltage source)." What is r? And what circle are you talking about?

-Dan