A forced commutated thyristorized step-down chopper is shown in the figure. Neglect the $\text{ON}$-state drop across the power devices. Assume that the capacitor is initially charged to $50 \mathrm{~V}$ with the polarity shown in the figure. The load current $\left(I_{L}\right)$ can be assumed to be constant at $10 \mathrm{~A}$. Initially, $\mathrm{Th}_{\mathrm{M}}$ is $\mathrm{ON}$ and $\mathrm{Th}_{\mathrm{A}}$ is OFF. The turn-off time available to $\mathrm{Th}_{\mathrm{M}}$ in microseconds, when $\mathrm{Th}_{\mathrm{A}}$ is triggered, is _____________ (rounded off to the nearest integer).
