The single phase ac voltage controller of the following figure has a 120 V rms 60 Hz source. The load resistance is 15 2. Determine a) the delay angle required to deliver 500 W to the load, b) the rms source current, c) the rms and average currents in the SCRs, d) the power factor, and e) the THD of the source current. Vs + S1 Vsw S2 32