An $$SCR$$ is considered to be a semi - controlled device because

Match the switch arrangements on the top row to be steady $$-$$ state $$V$$ - $$I$$ characteristics on the lower row. The steady state operating points are shown by large black dots.

In the chopper circuit shown, the main thyristor $$\left( {{T_M}} \right)$$ is operated at a duty ratio of $$0.8$$ which is much larger than the commutation interval. If the maximum allowable reapplied $${{dV} \over {dt}}$$ on $${T_M}$$ is $$50$$ $$V/\mu s,$$
what should be the theoretical minimum value of $${C_1}?$$. Assume current ripple through $${L_0}$$ to be negligible.

The Current Source Inverter shown in Figure is operated by alternately turning on thyristor pairs $$\left( {{T_1},\,\,{T_2}} \right)$$ and $$\left( {{T_3},\,\,{T_4}} \right).$$ If the load is purely resistive, the theoretical maximum output frequency obtainable will be