Induction circuits can be powerful, but they require a lot of power to run – especially at the input end. Even with a high-quality supply, the supply voltage may not be sufficient for an inductive circuit to work. We all need to know what our power supply voltage should be so we can feed it into the circuit and keep it stable.
Since the instantaneous voltage and current are zero whenever the instantaneous voltage or current (p=ie) is zero, it follows that the instantaneous power is zero when either power is zero.
