Transient States in RL Circuits: The Journey to Steady-State
(Refresh the browser once more for the equations to load properly) Transient States in RL Circuits: The Journey to Steady-State In this article, we attempt to obtain the complete solution of an RL circuit, including the transient state. We first consider the case of a DC voltage, where the current gradually builds up and after that, we take up the special case of AC Voltage which is often skipped in elementary courses. Fig: Growth of current in cases of DC and AC voltages DC Voltage: A DC Voltage refers to a steady voltage that does not vary with time. The below diagram shows a simple DC circuit involving a resistor `R` and an inductor `L`. A cell acts as the source of a DC emf E. Fig: A simple RL circuit with DC emf From Kirchhoff's Voltage Law, we know that the magnitude of the net Voltage drop across a loop is equal to the magnitude of the net emf in that loop. The voltage drop due to the resistor is `iR` and due to the inductor is `L \frac{di}{dt}`. Thus we m...