Question

Why does power supply decrease when you add additional resistors in series? (For example, using 3 resistors in series versus 4 resistors in series) I understand that as you increase the number of resistors in series, it increases the equivalent resistance. If the equivalent resistance increases, and the voltage stays the same, then the current decreases (V=IR). Then you can say P=V^2/R, which means that the power decreases, right? But shouldn't the total power be the same as the first situation? I understand that the, say, lightbulbs would be dimmer, but wouldn't the overall power be the same?

Answer 1

When the resistors connected in series it adding up more resistance hence less power will be delivered. By the conservation of energy the out put power must be equal to the dissipated power of the resistors. So as we increase the resistors in series it also increases its dissipated power so the light bulbs would be dimmer. So from conservation of energy amount of power being dissipating in the circuit at all resistors must be equal to the power supplied.