In a junction diode

The transfer function of simple RC network functioning as a controller is $$$G\,{}_c\left( s \right)\,\,\,\,{{s + {z_1}} \over {s + {p_1}}}$$$

The condition for the RC network to act as a phase lead controller is

The resonant frequency of this series circuit shown in figure is

The switch $$S$$ in figure is thrown to position $$'a'$$ at $$t = 0$$. At $$t = 1$$ second, the switch is thrown to position $$'b'$$. Find the current through $${R_2}$$ for $$ t > 1$$ sec.