Very interesting Setup from Mega Motors

[BrianG]

I just read the that HSW article and I didn't particularly like their lightbulb example. The way it was stated led the reader to believe a 100W lightbulb will always produce 100W no matter the applied voltage.

The incandescent lightbulb is also a bad example because the filament does not have a linear resistance either. Its resistance is close to 0 when no current is flowing (off) and the resistance increases as it heats up from the current flow. Incidentally, this is why a bulb amost always blows when you first turn it on - from the initial inrush of current while the filament resistance is lowest.