Difficulty: Easy
Correct Answer: Correct
Explanation:
Introduction / Context:
Inductors behave differently during transients and in steady-state. In DC steady-state, an ideal inductor has zero voltage across it (di/dt = 0), acting as a short circuit. Therefore, the loop's resistances determine the final current value, a key point in power supply and relay driver design.
Given Data / Assumptions:
Concept / Approach:
In steady DC, di/dt = 0 implies v_L = L * 0 = 0. KVL then reduces the loop to the source voltage dropping entirely across resistive elements, so I_DC = V_source / R_total. The inductance value L influenced the transient ramp rate but not the final DC current (for an ideal inductor).
Step-by-Step Solution:
Verification / Alternative check:
Measure current after a long time in a series RL step response; the final current equals V/R_total, independent of L (though the time constant tau = L/R_total set the rise time).
Why Other Options Are Wrong:
Common Pitfalls:
Confusing the time constant (which uses L) with the final steady-state current; overlooking small but present winding resistance in real inductors that should be included in R_total.
Final Answer:
Correct
Discussion & Comments