Studiot: Hm. I think I see the direction you're going. But let me ask with a simplistic example: Let's say we have a basic battery based circuit with a small 10 watt bulb and 2 batteries: one that is able to produce (or be drawn from) 30W and another at 20W. First you use the 30W battery in the circuit and you get a X lumens. Then, using the same 10W bulb, you switch to the 20W battery but this time you get an increase to Y lumens (I changed my example a bit).

If the two batteries have the same voltage, than the power the bulb draws will be the same - 10W. It doesnt matter how many watts your power source is capable of, only the voltage matters.

 

I think I see the direction you're going

Unfortunately you didn't see the direction.

I asked a simple question, which was:

Take a bulb and connect it to a power source so that it draws X watts.

How do you intend to cause that bulb to draw Y watts?

For your information it is the load (bulb) that determines the power not the supply.

 

you can not "give ' something less watts. you can lower the voltage, whitch will reduce the current, giving less watts, but it is up to the load to "take " the watts. like trying to force feed something, loads dont like it. and less watts means less lumens output because of less power supplied.

 

Actually, I did see the direction you were going in. Meaning, saying that the load determines the power, not the supply is what I thought you were going to say. Thanks!

WBahn I think provided a subtenant and relevant answer and seemed to truly get the spirit of what I was asking and restated it better.