Electric Potential: Explaining the Basics

[Niles]

I've read some litterature about the electric potential (V, volts), but I feel like I still miss an actual explanation of what this really is. I know it's "potential energy per unit charge", but I am searching for a more down-to-earth explanation.

Is it an "elementary" phenomenon, like electric fields?

Can I have a negative electric field in a positive potential field?

 

[BryanP]

Voltage is basically the ability to move an electrical charge through resistance.

Wiki has a good explanation for it.

Here's an analogy to it:

If one imagines water circulating in a network of pipes, driven by pumps in the absence of gravity, as an analogy of an electrical circuit, then the potential difference corresponds to the fluid pressure difference between two points. If there is a pressure difference between two points, then water flowing from the first point to the second will be able to do work, such as driving a turbine.

This hydraulic analogy is a useful method of teaching a range of electrical concepts. In a hydraulic system, the work done to move water is equal to the pressure multiplied by the volume of water moved. Similarly, in an electrical circuit, the work done to move electrons or other charge-carriers is equal to 'electrical pressure' (an old term for voltage) multiplied by the quantity of electrical charge moved. Voltage is a convenient way of quantifying the ability to do work. In relation to electric current, the larger the gradient (voltage or hydraulic) the greater the current (assuming resistance is constant).

 

[Doc Al]

Is it an "elementary" phenomenon, like electric fields?

Think of it as an alternate way of viewing the same thing. Potential takes an "energy" view, while the electric field takes a "force" view. But given the potential you can calculate the field. See: http://hyperphysics.phy-astr.gsu.edu/Hbase/electric/efromv.html#c1"

Can I have a negative electric field in a positive potential field?

Sure. The electric field is related to the slope of the potential field. Think of the potential field like a hill--the slope at any point represents the electric field strength at that point.