A2L Item 250

Goal: Reason regarding RL circuits.

Source: 283 – energy dissipated in inductor

Consider the following circuit. The switch S is closed at t = 0.
The total energy dissipated in the resistor before the current reaches
its maximum value is:

  1. V^2^/2R
  2. LV^2^/2R2
  3. LV
  4. V/RL
  5. none of the above



(5) The total work done by the battery is QV where Q is a function of
time which is not limited. The total energy stored in the inductor is
finite. The difference must be the energy dissipated in the resistor.
Since it takes an infinite amount of time for the current to reach its
maximum value, the total amount of energy dissipated is also maximum.

A good follow up question is: Is there a time when the dissipated energy
is equal to the stored energy? If so, what is that time?