E and V are the same (voltage)
I= Current. (Voltage = Current X Resistance)
It is a math equation you alter the resistance (E=IR so 12= 2*6 for instance)
double the resistance but keep voltage the same (12= 1*12) then the CURRENT is altered.
In DC- Voltage is determined by your source, only the CURRENT can be changed.
on an AC circuit the CURRENT and Voltage can be changed through the use of a step up or step down transformer. That's how you alter the current and voltage on AC circuits.
DC- battery power (cannot alter V unless you have more than one battery) AC= non storable power (can alter V and I with transformers)
In the context of AC voltage he is correct- assuming step up or step down transformers.
There.
rjp
EDIT- congratulations, tell your nerd friend you are correct. For once
