TriX wrote:
E=IR (or I=E/R) and P=IE. can't get any more basic than that. For a given resistance (R), increasing the voltage increases the current, and the power is the product of the voltage x current. For a FIXED resistance load, changing the voltage ALWAYS changes the current. Ohm's law... By way of your water analogy, think of voltage as the water pressure, resistance is the hose diameter, and the current as the amount of flow.
Your math only works if you don't change the electronic components you are putting the charge through; then of course you could blow the circuit or fry the parts too. Voltage and current can be totally controlled. Look on all those power supplies you have fro all the electronic parts you have on the house and read the voltage and currents they deliver; they will all be different in one way or another. I am in engineering in this with a degree and know what I am talking about. Have you ever heard of resistors, diodes, capacitors, inductors, transistors and all the other circuit parts; what do you think they do?