#172 

Really great explanation! I hadn't looked at slew-rate limited signals on the scope like that -- very good way of showing the problem.

The way you explained slew rate was the best I've ever heard or read anywhere. Great job!

Excellent descriptions as always. Thanks for taking the time to put this together.

Thank you so much for working on publishing this video. You have marvelously explained the difference between operational amplifiers gain BW limit and slew rate. Hats off.

Wow that is such a great class! Thank you for sharing such knowledge!

Just watched like 10 of your videos, great stuff!

Best explanation of slew rate and GBP

That is my dream oscilloscope. I regret not buying it when i bought an expensive one. I have the tds2002c which i use more haha. That scope is how old now and still holds its value and has a floppy drive. Tektronix are the best. Im restoring one for a friend. Hes had it in storage for a few decades so im not even sure what the model is. If i knew i could get that scope id sell almost all my gear. I tend to donate my gear when i get new gear. The tek diff probes are so expensive. Id trade my rigol mso5354 and every other piece of gear for that scope and a nice selection of probes. There's a reason you work for them but havent replaced the 3104. Great video, thanks. Ive found that i had to buy caps that are above my budget to get most opamp circuits to look as perfect as yours. Sorry for rambling i have severe ptsd. I shall get my ham license in the new year.

Exceptional explanation. Precise and compact, thank you very much!!

Excellent information and demonstration thank you! I've been having refresh/learn things about op-amps lately for our senior project and this video helped very much!

This is absolutely brilliant. Very well explained. Now I can sleep on class and learn at home!

Brilliant video. Suddenly I understand why my home brew function generator acts wired at higher frequencies. Thanks a lot.

Super clear . Thank you for doing this video. Liked and subscribed

A very, very well done, easy to understand explanation. Link to video instantly forwarded to my hobby network.

Nice explanation about slew rate!!! Very helpful!

This is great stuff, I just came across phase reversal on a LF353 working as a voltage follower when reaching Gnd. Luckily I also bought TLC272 that did that job perfectly single supply. I know it was a rookie mistake but what better way to learn.

Fantastic video and all in 15:30 minuts !

Stellar video. Thank you so much for the great lesson & demo.

This was extremely concise and well paced and informative. Thanks so much for your videos! I had a few questions about the caps in your test circuit. I'm assuming the 0.1uF cap going from your divider reference to ground is a bypass cap to limit noise from the op amp, right? As for the 220uF coupling cap, was there any reasoning in picking that value or is it what you had on hand? Additionally, would this cap and the input impedance of the op amp form a high-pass filter? It seems like the 3db point would be nearly 0? I'm still learning the fundamentals and trying to piece together all these EE ideas in an intuitive way. Your videos have helped immensely in that quest. Thanks again

Dear w2aew, I really am a big fan of your videos, this time however I was surprised to notice you made a common mistake at around 2:23. You are saying that for a single pole response the product of the DC-gain and the bandwidth is constant, however this is _not_ true for the inverting amplifier you are demonstrating: it should be: (1+R2/R1)*BW=unity gain frequency. As long as R2/R1 is much larger (10 times or more) than one, the difference in bandwidth will not be that large, but for small values of R2/R1the difference between your prediction and the correct formula can be a factor 2! If the unity gain frequency of your op amp is 1MHz you should expect for a single pole response a bandwidth of 500kHz and not 1MHz. This also means that the -20dB/dec slopes of the closed loop configurations will not touch the -20dB/dec slope of the open loop system, but will be shifted to the left of it. Unfortunately you did not measure the small signal bandwidth for R2/R1=1, you should apply an input voltage whose amplitude is small enough not to have slew rate distortion. I wrote an article concerning this matter "A closer look at the slew rate criterion" in 2004. Maybe you could check it out and remeasure the bandwidth for R2/R1=1. In reality you probably will find a somewhat higher bandwidth due to the fact that a real op amp always is a higher order system, which especially can be seen in the case where R2/R1=1, sometimes noticeable as peaking in the amplitude characteristic, the asymptotic slope of the amplifier being steeper than -20dB/dec and the phase characteristic shifting over more than 90° relative to the phase at low frequencies. kind regards, Hugo

As usual, so clear to make me understand at first time! Are IC switching power regulators in your "to do" list?

Very good explanation....Learned the concept practically..just amazing

Thanks for such quality tutorial!

Great as always! Thank you!

Holy shit mate, i just noticed the scope you have, That's a serious instrument, around $40,000 if i'm not mistaken.......VERY COOL 1GHz on the front end

Thank you Alan. Superb....

Fantastic as always, thanks.

Thanks again, Alan. Great vid.

As always a great video! :)

thanks a lot from the depth of my heart

Excellent explanation!

Really as always. Great teacher

I was thinking, if you put two common emmiter transistor amps on the output of the opamp and take feedback from the collector resistor of the second transistor back to the opamp feedback resistor network, would that somehow enhance slew rate or/and the gBW product?

I’ve been trying to find a single step attenuator like wavetek you have in the video but unable to find anywhere. Can you recommend any alternative to the wavetek ? . I’d love to run these tests as well

Very informative, thanks!

Hi, I'm using TLV3501 comparator (it hash push-pull outputs) (SOT23 6 Pin) for zero cross detection. I'm powering it from single supply (5v).comparator output goes high to ~5v no issue with that, but the comparator output when outputing low doesn't go near 0v, instead it stays at vdd/2. Can you give your insights on why this might be happening?.

Great work man,keep up

Why are you specifically looking for the 3 db point?

thumbs up before I watched it - for the topic

thank you very much

Brilliant video. What opamp should I use to amplify a 1mhz audio signal by 20db?

So if I want to have an useful gain for for example 27 MHz so I need like an ultra fast Op Amp right? Like 1 Ghz at least ?

Thanks for this awesome video

hey, i was wondering if you have a vector network analyzer in your lab?

Thank you.

can anyone please tell me what is the purpose of the 2.2k ohm resistor at the output,or how this configuration called so i can learn about it. thank you

Slew rates are awesome.

Brilliant!!

***** Thanks for the video. Is it possible to build an amplifier using LM741 to generate an output voltage of 50 V?

👍

hi

bruh

the demonstration of the slew rate limiting the frequency response of the opamp was so sweet!!!! I have not done the connection between slew rate and freq response.

Excellent! You laid out in 15 minuets what it took for me; three months of college study to understand back in 1986, with some help from Walter Jung, of course. Alan, you did an outstanding job! Thanks for your hard work.You make it look so easy however, I'm well aware that it takes a lot of hard work, not only for the concept and math, circuit design and build but the mere production of these videos. Thank you so very much for your hard work to make electronics so easy for saps like me...!

Thank you very much for sharing. Very insightful explanation.

awesome job explaining. Super helpful, thanks

Really great explaination and to the point ,you are inspiration to many

Awesome tutorial. Thank you!

Fantastic teaching.

That all makes a lot of sense. You can tell a great teacher, it seems obvious as they explain things.

Very good demonstration. I have read slew rate in datasheet often but understood it really with this demonstration and explanation. I like the attenuation box you use.

Platinum!!

Brilliant video. Suddenly I understand why my home brew function generator acts wired at higher frequencies. Thanks a lot.

Brilliant explanation as usual. Thank you. A tear fell when you pulled out the datasheet "book". Excellent.

It seems to me, that in most applications we wouldn't want to be slew rate limited. That is, we would want to hit the 3dB corner (f_3dB), or the full power BW, before we hit the slew rate frequency (f_SR). We can check if this is the case from the op-amp's data sheet, which gives us its GBP (gain-bw-product) and its SR (slew-rate). We have: GBP = (A_CL)(f_3dB) or f_3dB = GBP/A_CL. We also have SR = 2(pi)(Vout_pk)(f_SR) , or f_SR = SR/((2pi)(Vo_pk)). Using Vo_pk = (Vin_pk)(A_CL) this last equation can be written as f_SR = SR/((2pi)(Vin_pk)(A_CL)). So we need f_SR > f_3dB, or SR/((2pi)(Vin_pk)(A_CL)) > GBP/A_CL, or SR/((2pi)(Vin_pk)) > GBP. If this isn't true then our application needs an op-amp with a larger SR and or a smaller GBP (or we need a redesign where we start with a smaller input signal Vin_pk). Am I thinking about this correctly? Thanks!! And beautiful job on teaching about closed loop f_3dB and SR !!.

An Exceptional Narration!

Interesting info. Will be fun to repeat this experiment

your videos are helpful as they are more practical and hands on..thanks for it

Thanks a lot, exelent video, keep up the good work :-)

Is there any difference in gain bandwidth product between inverting amp and non-inverting amp while calculating V out ? I mean I watched a video regarding GBP and teller said Fu = Acl x Fcl in Non-invering amp Fu= ( |Acl |+ 1 ) x Fcl in inverting opamp Does it make sense ?

Thank you for the nice video. Great stuff

Excellent!!! It is interesting how the slew rate of the op amp is not affected by the frequency of the signal but basically by the amplitude of the signal.

Very nice! thanks :)

Thanks very much.

Thank for share, very usefull for me, for make good preamp Regards,

Thank you for the video and clear explanation i have learned soemthing new today.

A fascinating demonstration. Regarding the phase delay introduced when the slew rate limit is reached: is this a constant? You pointed out that the falling edge has a slightly different slope than the leading edge and this was clearly seen. Two thoughts on this. (1) is this predictable enough that it has utility in a design? and (2) as a phase delay appears to be present (although you didn't show the waveform just out of the signal generator), is this useful in certain applications - and perhaps undesirable in others?

Why did you stop increasing the frequency when the voltage dropped to 700mV?

At minute 3:38 the formula for BW is very similar to the formula for calculating the scope BW based on the signal rise time. The diff is in the 0.35 constant. Are they really related?

This is briliant explanation. Thank you.

Good video!

Please keep doing. You have found the optimal way to merge theory and practice. I have studied these "boring " things over 20 years ago. Now they are exiting thanks your videos.

Many many thanks to you, I'm designing a 2-switch forward converter, and need to do with op-amp feedback compensation. This video make me recall things on my electronics class. :) :)

beautiful demo of knowledge...you really understand electronic! as ham radio op. i'm proud about you..9A3RU

Very helpful video, everything is described in a very calm and demystifying manner.

Very well composed video. You are the best in explaining the basic things.

Why have you used 470uf and 0.1uf capacitor in this circuit.

Really helpful explanation. Can you make a video on opamp stability and capacitive loading ? It really helps the way you explain it with actual demo. thanks again.

Thanks for the heads up in the other comment section. I have watched this video a few times before. My op amp tester is based on a similar type of circuit with a dual polarity supply instead of the bias. I guess my challenge is to learn how to replicate what your doing with the function generator. ..Without a function generator...yet 🤔 ...but with predictable, repeatable results.. 🙄 My snipe hunting list for eBay is getting ridiculous... I'm starting to think hotrodding cars was the cheaper hobby. Thanks again, -Jake

Thanks Alan. It's always a pleasure learning from your videos.

🌹🌟🌹

How didi u select the value of resistors and capacitors

Thank you for your efforts. This is an excellent video.

what is purpose to use 470uf cap on non inverting line.

Thank you so much for the explanation of the slew rate, helped me a lot!

Great video, thanks a lot.

great explanation thank you :-) u r very good!!

can u tell me plz how u calculate 707mv....

Awesome practical demo! I really appreciate the balance between theory and real-life measurements.

Hey Alan, Thanks for uploading another great video! I hate to be picky, but I noticed something in your diagram of slew-rate-limiting at 10:20. You drew the slew-rate limited waveform being in-phase with the the input signal (or a non-slew-rate-limited output signal). However, shouldn't the slew-rate-limited signal lag the input signal by some phase?