The triac circuit shown in figure controls the $$ac$$ output power to the resistive load. The peak power dissipation in the load is

Figure shows a chopper operating from a $$100$$ $$V$$ $$dc$$ input. The duty ratio of the main switch $$S$$ is $$0.8.$$ The load is sufficiently inductive so that the load current is ripple free. The average current through the diode $$D$$ under steady state is

Figure shows a chopper. The device $${S_1}$$ is the main switching device. $${S_2}$$ is the auxiliary commutation device. $${S_1}$$ is rated for $$400V, 60A.$$ $${S_2}$$ is rated for $$400V, 30 A.$$ the load current is $$20$$ $$A.$$ The main device operates with a duty ratio of $$0.5.$$ The peak current through $${S_1}$$ is

The circuit in figure shows a $$3$$ $$-$$ phase half $$-$$ wave rectifier. The source is a symmetrical, $$3$$ $$-$$ phase four $$-$$ wire system. The line-to-line voltage of the source is $$100 V.$$ The supply frequency is $$400$$ $$Hz.$$ The ripple frequency at the output is