Question

A 2 V step function is applied as input to a non-inverting amplifier with a closed loop gain of 2.5 V/V. If the slew rate of the op-amp is $2V/\mu sec$, then the time needed for the output voltage to reach its full scale response corresponding to the applied input voltage is equal to____________$\mu sec.$
$\text{(Assume that, initially the op-amp has}{V}_{out}=0V\text{)}$

• A. 10
• B. 2.5
• C. 5
• D. 1

Answer 1

The correct option is B 2.5

$V_{out}=A_{CL}\times V_{in}=2.5\times 2=5V$

$\text{Now slew rate,}\frac{\Delta V_0}{\Delta t}=2V/\mu sec$

$\therefore$ $\text{For output to rise from 0 to 5 V.}$

$\therefore$ $\frac{0-5}{0-t_0}=2V/\mu sec$

$\therefore$ $t_0=\frac{5}{2}\times {10}^{-6}sec=2.5\mu sec$