The input resistance $${R_{IN}}\left( { = {V_x}/{I_x}} \right)$$ of the circuit in the figure is

Assuming the operational amplifier to be ideal, the gain $${V_{out}}/{V_{in}}$$ for the circuit shown in figure

The output voltage$$\left( {{V_0}} \right)$$ of the Schmitt trigger shown in figure swings between $$+15V$$ and $$–15V.$$ Assume that the operational amplifier is ideal. The output will change from $$+15V$$ to $$–15V$$ when the instantaneous value of the input sine wave is

For the oscillator circuit shown in figure, the expression for the time period of oscillations can be given by (where $$\tau = RC$$ )