If an ideal inductor is connected directly (no resistor present) to a DC voltage source, why does it behave like a short-circuit at time t=0? If voltage across an inductor is related to the change in current (i.e. di/dt), then shouldn't the voltage across the inductor be very large at time t=0 because the current goes from zero to some value instantaneously (assume no resistor is series). This would imply that the inductor should act like an open-circuit at time t=0. Wouldn't the inductor oppose the initial current spike and prevent the initial current from flowing? I know that this is not true; however, I am trying to determine why not. Thanks for your help.