Are amps provided or drawn?
The whole plumbing analogy for electrical current flow breaks down pretty quickly, but in this case it may just work:

You walk up to your kitchen faucet.  It's off.  There's pressure behind the valve (40-ish PSI), but no flow.  That's like an electrical outlet with nothing plugged in.

You open the faucet just a bit.  Water flows just a bit.  That's like plugging a night-light into that outlet.  You open the faucet a lot.  A lot of water flows.  That's like plugging in a light fixture, or turning on a vacuum.

Beyond that the analogy breaks down: electricity has to flow in a circuit, while the water that goes down the drain may take centuries to fall as rain again; your pipes don't burn up if you flow water through them too fast, etc.  But that's the basic idea.

It's complicated, but:


usually a source will provide a fairly constant voltage unless the load is asking for too many amps.
A load will almost always pull a certain current for a given input voltage, or maybe the current will change with the state of the load (like a battery charging, and using less current as it gets more charged).
An unprotected source will often heat up, burn up, or otherwise be unhappy if you pull too much from it -- power wiring has fuses on it to prevent this from happening, because the inconvenience of changing a fuse or flipping a breaker is usually less than the inconvenience of rebuilding a burnt-down house.
Etc.  There's more, but -- it's complicated.  Hopefully this gives you a start.