Op Amps: Measuring Slew Rate

Slew rate is defined as the maximum rate of change of output voltage with respect to time. It is important to note that this has nothing to do with the gain of the amplifier. Amplifiers with high gain, as well as those with low gain, can suffer from slewing. In this video, we look at a quick way of determining the slew rate of an amplifier, as you would in lab. We also discuss potential issues with rise time.
Reference: Operational Amplifiers: Theory and Application, Chapter 5.
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[@leiferickson3183]

Why does the output have a kink prior to the input changing at 9:13 (at the begiining of the rise time)? This was also visible on the 1kHz signal as well.

[@ElectronicswithProfessorFiore]

Without diving into it, I suspect that is due to the finite time resolution of the sim. Note that we have zoomed into the plot. Time domain plots only compute a certain number of points. Having said that, you will sometimes see slew limiting that changes slope. This is due to the internal characteristics of the op amp.

[@laurentcouturet6936]

Thank you for posting all your videos. I've just got some of your textbooks, which I'm sure will be very helpfull (DC & AC for the time being as I need a strong refresher...). There are many exercices after each chapter, which is good to verify that the chapter is "understood". Although it's written that answers are available for most 'Analysis' odd-numbered exercices. I didn't find any answers for 'Design' and 'Challenge' exercices. Sometimes it's hard to believe we got it right and reassure ourselves that progress is made if our answers cannot be checked against anything. Your comments will be welcome.

[@ElectronicswithProfessorFiore]

This is a common questions that I get. There is a rationale for this. First, I don't include answers to all problems because these texts are used at colleges and universities, and professors assign some of these problems for graded homework. This is particularly true for the challenge and design exercises. Second, if you have doubts, remember that you can always capture the circuit in a simulator to check the results.

[@cougar1861]

In the absence of conditions promoting rise-time effects, may we assume constant slew rate vs frequency?

[@ElectronicswithProfessorFiore]

Yes. Slew rate effects will be more pronounced on higher frequency signals though (assuming same amplitude).

[@cougar1861]

@@ElectronicswithProfessorFiore Thanks

[@andymouse]

Nice....cheers.