Originally Posted by Vick!

I understand what you mean. But mate, when we say 'right' voltage -- Its mean we are limiting the voltage to a certain level which do not harm the circuit (LED). As long as concern to limit the current, we do not limit. It get limited on its own depending on the internal resistance of the circuit (LED).


For example, attach two batteries of 1.5 volts each to make 3 volts, right? Then attach an LED to it, LED will be ON.

Did we limit the current? No, current is automatically remain within limit of approx 15-20mA due to the internal resistance.


Ohm's Law comes here, at constant resistance current and voltage are directly proportional. So, limiting voltage is actually limiting current as well.
You are also right in one way. But again, to limit the current we actually limit voltage, assuming resistance is constant.