Pulse-width modulation is used to provide a 60-Hz voltage across a series RL load with R = 12 and L = 20 mH. The dc supply voltage is 150 V. The amplitude of the 60-Hz voltage is to be 120 V. Use PSpice to obtain the current waveform in the load and the THD of the current waveform in the load. Use () bipolar PWM with m= 21, (b) bipolar PWM with m=41,and (c) unipolar PWM with m=10.