An unipolar PWM full bridge circuit has a VAN and VBN of 175V and 125V respectively. It also has a Vd that is 4 times Vo. What is Vo? What is Vd? What are the duty cycles D1 and D2? Then calculate the Vr.rms at D1. Now calculate vr.rms at each duty cycle D1 from 0 to 1, with 0.1 steps in between. When is Vr.rms minimal and maximum based on terms of D1?