Question

Calculate the time taken by the output to swing from +14v to -14v for a 741C op-amp having a slew rate of 0.5V/µs?

(a) 22µs

(b) 42µs

(c) 56µs

(d) 70µs

The question was asked by my college professor while I was bunking the class.

Question is taken from Slew Rate in portion Practical Limitations of Op Amp Circuits of Linear Integrated Circuits

Answer 1

To calculate the time taken for the output to swing from +14V to -14V, we can use the formula for the time required for a voltage change given the slew rate.

The slew rate $SR$ is defined as the maximum rate of change of the output voltage, which is given as $0.5\text{V/µs}$.

The total voltage swing is from +14V to -14V, so the total voltage change is:

ΔV=Vfinal−Vinitial=−14V−(+14V)=−28V\Delta V = V_{\text{final}} - V_{\text{initial}} = -14V - (+14V) = -28VΔV=Vfinal​−Vinitial​=−14V−(+14V)=−28V

Now, using the slew rate to calculate the time:

Time=ΔVSlew Rate=28V0.5V/μs=56μs\text{Time} = \frac{\Delta V}{\text{Slew Rate}} = \frac{28V}{0.5V/\mu s} = 56 \mu sTime=Slew RateΔV​=0.5V/μs28V​=56μs

Thus, the time taken for the output to swing from +14V to -14V is 56µs.

The correct answer is:

(c) 56µs.