A full-wave rectifier bridge supplying a 20 2 resistive load via an a.c. voltage controller from an ideal single-phase supply vs Vm sinot in an arrangement as shown Fig.5.11. The SCRs of the inverse-parallel pair are gated to provide symmetrical phase-angle triggering. (a) Sketch waveforms, for two cycles of the supply voltage, load current and supply current. (b) Derive an expression for the load power dissipation in terms of Vm, R and a. Calculate the power at a = 30 if Vm = 230 V. (c) If diode D1 is failed to open circuit, what will be the value of the load current? v=Vmsin cot Fig.5.11. D D D. D R