This example illustrates how a large negative voltage can be generated by switching an RL circuit. Since an inductor looks like a short circuit "after a long time", all 100 mA gos through the inductor, so I_initial = 100 mA. When the switch changes positions, the inductor's collapsing magnetic field keeps current flowing from its top to bottom terminal. The current flows through the ground connection, then through the resistor from the bottom to top terminal, meaning that the top terminal (our V_out) is negative with respect to ground. V_out = -I*R, so we can achieve a large negative voltage by choosing a large resistor.
NOTE: The noisy jumps in the output voltage is a simulation artefact and not related to the circuit functionality.
