A general filter circuit is shown in figure

The output of the filter in above is given to the circuit shown in figure The gain $${V_S}$$ frequency characteristic of the $$0/p$$ $$\left( {{V_0}} \right)$$ will be

The input signal $${V_{in}}$$ shown in the figure is a $$1$$ $$kHz$$ square wave voltage that alternates between $$+7V$$ and $$-7V$$ with a $$50\% $$ duty cycle. Both transistors have the same current gain, which is large. The circuit delivers power to the load resistor $${R_L}.$$ What is the efficiency of this circuit for the given input? Choose the closest answer.

The switch $$'S'$$ is the circuit of the figure is initially closed. It is opened at time $$t=0.$$ You may neglect the zener diode forward voltage drops. What is the behavior of $${V_{OUT}}$$ for $$t > 0$$

A relaxation oscillator is made using op-amp as shown in figure. The supply Voltage of the op-amp are $$ \pm 12$$ the voltage waveform at point $$'p'$$ will be