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.

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

In the given figure, if the input is a sinusoidal signal, the output-will appear as shown

Consider the inverting amplifier, using an ideal operational amplifier shown in figure. The designer wishes to realize the input resistance seen by the small signal source to be as large as possible, while keeping the voltage gain between $$–10$$ and $$–25.$$ the upper limit on $${R_F}$$ is $$1\,M\Omega .$$ The value of $${R_1}$$ should be