In a RL DC circuit, as the current rises, what happens to the voltage across the inductor?

In a RL DC circuit, as the current rises, the voltage across the inductor decreases. This occurs due to the nature of inductors in response to changing current. When current begins to flow in the circuit, the inductor opposes the change through its property of self-inductance.

Initially, when the current is increasing, the inductor generates a back electromotive force (EMF) that opposes the increase in current. The inductor does this by creating a voltage drop across its terminals, which is proportional to the rate of change of current over time (described by the formula ( V_L = L \frac{di}{dt} )). As the current continues to rise and approaches its maximum steady-state value, the rate of change of current (( \frac{di}{dt} )) decreases, leading to a drop in the voltage across the inductor. Ultimately, once the current stabilizes, the inductor behaves like a short circuit, and the voltage across it approaches zero.

This understanding of the inductor's behavior is crucial when analyzing transient responses in RL circuits, allowing for predictions about voltage and current relationships over time.