Well, R is *almost* fixed...
In this case, similar to a lightbulb, the more current goes through, the higher the resistance will be.
The current draw is defined by the resistance and the voltage applied: it is not affected by the type of power supply.
To get less than 150 Watts, you would lower the voltage (from 40), which would in turn lower the amps (from 3.75), and as a result, the power (P=V * I).
|