Current Questions

Thank you everyone for trying to drag me into the light. 
 

Unfortunately it seems that the light isn’t so bright. The implication of Terry9’s post—take off the cover and look for this and that—is that there isn’t a spec I can look at and get quick understanding of a given amplifier’s current capabilities. No equivalent of watts as it relates to power. Is that right? Nothing that will give me even a rough idea? Something for fools like me who didn’t write a dissertation on Ohm’s law?
 

I could easily be wrong but it seems that, back in the 1980s and ‘90s, most every amp doubled in power as it moved from eight ohms to four. Like a manufacturer would be embarrassed if it didn’t. I think even my Harmon Karden 330c went from 20 watts to 40 as the impedance changed. (Dropped? Rose?) Is that just a warm, fuzzy feeling I’m getting from the past?

4krowme, we went to the same school of income tax preparation. I’d probably be better off if I stayed there for electronics. But I hate to be completely ignorant when talking to a salesman or reading glowing marketing materials. Knowledge is power and I don’t like being defenseless. 

Yo Holmz, I appreciate the effort but you lost me in the first line. Rails? Volts? In the the equation V = I R, I assume that V is volts but what is the other stuff?
 

Still, there may be some gold in the stream. Is current measured in amps? And since low impedance speakers are harder to drIve, does that mean that they require more current, i.e., more amps. Am I right so far? Where does volts fit into the picture?

So when someone says that a particular speaker needs a lot of current, he could just as easily say that a speaker is low impedance and needs a lot of amps. Does that make sense?

But I’m left with a big question. If it’s true that current is measured in amps, what is being measured? Some kind of energy? What kind of work does this energy do in a stereo system?