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

The circuit in figure shows a full-wave rectifier. The input voltage is $$230$$ $$V$$ $$(rms)$$ single-phase ac. The peak reverse voltage across the diodes $${D_1}$$ and $${D_2}$$ is

A $$MOSFET$$ rated for $$15 A,$$ carries a periodic current as shown in figure. The ON state resistance of the MOSFET is $$0.15$$ $$\Omega .$$ The average ON state loss in the $$MOSFET$$ is

The triggering circuit of a thyristor is shown in figure. The thyristor requires a gate current of $$10$$ $$mA,$$ for guaranteed turn-on. The value of $$R$$ required for the thyristor to turn on reliably under all conditions of $${V_b}$$ variation is