The document discusses two basic examples of power conversion circuits. The first is a simple half-wave rectifier with a resistive load that converts an AC input voltage into a DC output voltage. The second is a half-wave rectifier with a series inductor-resistor load, which operates differently due to the inductor. It explains how the diode turns on and off based on whether the voltage is forward or reversed biased, and discusses how the inductor current must reach zero for the diode to turn off.