Some Circuits I Questions?

Question

Hey I just have a conceptual question for ya. Can the instantaneous power absorbed by an energy storage element (Cap or Inductor) by a negative value? I'm just trying to get some answers to possible questions on a test I have coming up. My guess on this question would be yes it can, when it's discharging on the current is leaving the + terminal this disobeying PSC. Am I wrong?

Here's another one:

Is there any significant affect the RMS value has in relation to power absorbed by a resistor?

And lastly,

In a first order transient does voltage in an inductor always increase exponentially.

Just throw some answers at me with your thoughts, thanks!

Answer 1

The first, you are right, there can be instantaneous negative power in a reactive element.

The RMS value represents the effective heating power of the current or voltage, and as such the power absorbed by a resistor proportional to the RMS value squared.

In an inductor, the first order transient from an applied voltage (through a resistor) is an exponential increase in current. (Through a zero-impedance source, it is a linear increase in current.) The first order transient from an applied current is an exponential decrease in voltage.