How can voltage and current be out of phase?
When inductance is introduced into a circuit, the voltage and the current will be “out-of-phase,” meaning that the voltage and current do not cross zero, or reach their peaks and valleys at the same time. This phase shift occurs because the inductive reactance changes with changing current.
How can the total power of any circuit be zero?
In short, in a circuit where voltage or current leading or lagging 90° (phase difference = 90°) behind each other, the positive cycle cancel the negative which leads to the zero average power of the circuit i.e. the total power factor of the ac circuit is zero which leads to the zero average power.
Does voltage lead current?
Hence, when a sinusoidal voltage is applied to an inductor, the voltage leads the current by one-fourth of a cycle, or by a 90º phase angle. Current lags behind voltage, since inductors oppose change in current. Changing current induces an emf. This is considered an effective resistance of the inductor to AC.
How can there be a current without a voltage?
TL;DR Just as a capacitor can have a voltage across it with zero current, an inductor can have current running through it with zero voltage (indefinitely, if it’s superconducting). Thanks for contributing an answer to Electrical Engineering Stack Exchange!
What happens when there is no voltage in a capacitor?
Another instance of the same problem happens when charging a big capacitor. At first, there is essentially no voltage across it, but several dozens of amperes of current is going into it. Once again power, 0*I, is about zero, and yet the power is being consumed into the capacitor.
Can a solar cell draw a negligible voltage?
In practice, a real ammeter draws “negligible” voltage and uses that negligible voltage to sense current. And so, a solar cell actually delivers power, albeit “negligible”, to a real ammeter. Thank about your capacitor question again.
How does an ammeter work with no voltage?
Now in the case of an ammeter, an ideal ammeter is a device that draws no voltage (i.e. suffers no IR drop) but yet (somehow) measures current. In practice, a real ammeter draws “negligible” voltage and uses that negligible voltage to sense current.