EEVblog

I know this will probably get lost in the comments but I have to say it. I absolutely have a high respect for people like you who share knowledge so freely and willingly. People like you are a godsend. Thank you sincerely.

"The gain is almost infinite"
spoken like a true engineer!

Six years later, this is still the best and most understandable intro to Op Amps ever.

Hi dave I've been watching your channel a lot for the last couple years now and it's fantastic! I'm currently doing my honors in electronics engineering and my University here in hamilton New Zealand has instructed my class to watch this video on the current section we are covering on op-amps. You have finally made it to university level teaching my friend!

As a retired Senior Applications Engineer at Burr-Brown and Texas Instruments, I must compliment you on this presentation! It is very similar to the "factory" technical presentations that we used to give to audiences around the globe. The technical level is just right, not to basic and not too advanced. Good job! To be a good teacher it takes far more than just knowledge of the subject. A teacher's job is to impart knowledge to his student; if the student doesn't understand, the teacher is not doing his job. Some PhDs can teach, others can't- Richard Feynman was an example of a fellow who not only thoroughly understood his subject but who could teach it as well.... and do it in an interesting and entertaining manner.

The fact we can learn this and not have to go into debt... your a gift to engineering Dave!

Dave, this is amazing. Thank you for these mini classes, honestly it’s worth more than any electronics class I ever paid for.
Negative feedback op-amps just clicked into place for me about 10 minutes in. I had been struggling with this concept for days. Thank you so much.

this video got me my first electronic job i watched this video before my interview and they quizzed me on op amps! the luck!

I find myself revisiting this tutorial as a refresher every time I need to incorporate an OpAmp into one of my projects. Thanks Dave! 👍🏻

7 years on and your videos are still helping new technicians. I really appreciate this, thank you.

It's so great to see fellow Australians showing up on TheXvid. Especially for something like explaining electricity. Bringing fame and reputation to our country!

You are really great at this. I'm in a 3rd semester EET student and I learned a thing or two about op-amps from you. I should be paying you tuition!

If anyone is interested the gain of the non-inverting config can be derived from the voltage divider equation:
Vin = Vout*R1/(R1+Rf)
Vin/Vout = R1/(R1+Rf)
Vout/Vin = (R1+Rf)/R1
Vout/Vin = 1+Rf/R1
And the gain of the inverting config can be found from the currents:
I(Rf) = Vout/Rf
I(R1) = -Vin/R1
-> Current through both resistors is equal so...
-Vin/R1 = Vout/Rf
Vout/Vin = -Rf/R1
:)

If only I had the opportunity to watch this when I was learning about OpAmps some decades ago ! So much simpler to understand with you, Dave !

Even after 30 years away from electronics I got the gist of you lesson, thanks you explain it very well and in manner I just love. I worked in the dept of Navy as a trainee and we had two parts, one was a TAFE course the other was direct from Naval lecturers. The naval lecturers were like you extremely conversant and able to explain in a much more understandable manner.

You are the worlds best electronics teacher! I have watched all of the EEVblog's and I enjoy watching everyone of them!
Thanks Dave!

I am in my senior year for EE and we had a whole 8 weeks in one of my circuit theory classes dedicated solely to op amps. We got to delve deep into these and do some really fun design problems and lab experiments. This video really is a great refresher and good start for anyone new to them.

Regarding the puzzle at the end, the low resistance effect is an increased current at the OA output. the OA at approximately Vout= -0.5V should sink 50uA which is higher than the value in the datasheet/figure13 of 30uA max. so the virtual ground voltage fluctuates and so does the output at approx. -0.5V.

Took years to comprehend this stuff. Especially when it came to more complex circuitry and control of DC motors from controlling speed, current, volts, positioning, etc. Great video and spot on! Thanks

Love these. More, please. I've been using Op Amps and Comparators for decades and still learned a couple tricks watching this video!

Been a tech for 43 years and I have never seen it explained so concise. Thanks and I am turning the junior techs onto this video. Cheers!

Great teaching skills. Good job, very informative and easy to follow. Reminds me over 20 years ago my electronics teacher back at modesto high school in California, i did alot of VICA skills challenges it was fun and i use that information to this day

what makes you a gorgeous teacher is that you not only talk about what is going on but also about what the follower might think is going on but actually is not and why. i had so many frustrating experiences in the past because of teachers that did'nt care about that. i truly love your lessons.

When I learned how to use Op-Amps, the 741 was the state of the art at the time. Yes, had to learn them the hard way back in those days. What a great refresher course for this young man born 9-11-1946. Great job Dave and thank you. Respectfully, Steve

I spent few years in school to learn this (hundreds of years ago) but no teacher was able to present it so clearly like you did - thank you bro

Thanks for this video. Now I recommend it as the intro to OpAmp use in beginners electronics. Interesting to note that some students do not use transistors at all. it is easy for them to use dual OpAmp chips rather than use several transistor stages =)) They do not even know how transistors work in signal amplify mode!

This is my new favorite TheXvid channel!!! I am a marine engineer by trade, but I started getting bored, so I signed up for an online electronic engineering programme at my local university, to put my spare time into good use.
I have never gained much from sitting in a classroom listening to a lecturer bleating for two hours at a blackboard, so I was thrilled, when I got the opportunity to work at getting a degree, working by myself at home. These videos are an absolutely excellent supplement to all the videos available from my university.
Thank you!!!

In my whole electronics major shit , I have never seen a person who explains virtual ground like this.
#RESPECT

Great video. For an electronics novice I learned more than I was expecting.
Subscribed.

Thank you Dave! This video has saved me headaches on multiple occasions. Everything is so well explained. I keep coming back to it for reference.

You are a life saver. I hope you did more videos like this.
I am glad to have benefitted from your knowledge.

This is probably the most comprehensive and effective explanation I've ever watched about opamps. You sir are a pedagogical genius!

Well, I secured more marks than my friends in our exam just by watching this video 2 hour prior to my exam. Thanks Dave.

Brilliant, learnt more in 20 mins that I did in a year of full time study, thanks for all your great videos! ;)

wish I found this when I took circuit theory, you make it so much more fun than my professor does

Very helpful. I'm an electronics technician and you see this stuff when you're doing repairs or troubleshooting but you never get down to the nitty gritty details especially after 30+ or so years goes by from your initial electronics training so it was really nice of you to explain this especially on layman's terms. Someone else mentioned in this blog about cutting and pasting working circuits into projects and calculating as you went along to fit your needs which is pretty much what I've done in the past so this has really been a BIG help in the memory refresh department. Thank you ten times over and may the "electro" Gods shine good fortune down upon you sir!

Just great, a topic I always left apart until you discover it to me. I suppose there are LOTS of applications but it's great to learn that way. A lot of things I discovered! Thank you so much!

This was great! At the same time I was learning how to make a CPU from Ben Eater channel. It occur to me that it would be awesome if someone start an RF project and explain main RF concepts along the way when it is needed, as Ben did. Thank you again

Your videos are simply outstanding. I love learning about things and messing with electronics is one of my hobbies. Thanks for taking the time to make this and all your other videos.

FINALLY!!!! A video that ACTUALLY EXPLAINS HOW IT WORKS!!!!!
Dave, this video was a godsend.

Thanks for doing teaching vids, Dave! I took many electrical engineering courses in college and we did a lot with op-amps, but I'm embarrassed to admit I've completely forgotten everything about them since then. These practical introduction videos are perfect for people like me who want to reconnect to something we learned in the past. Thanks again!

I finally understand these, I was struggling in my lectures because my professor just couldn't explain them. Thank you so much!!!

This was amazing, thank you! I'm just a hobbyist but I got all of what you presented. It's the first of your videos I've seen. Now I have a looot of watching to do!

Great lesson! Clear and to the point! Thank you.

Great tutorial. Easy to understand, esp. from a perspective of understanding what's going on if one sees an electronic drawing and knows what's going on there.

I enjoy benefiting from all of your videos, but this one has given me confidence to breadboard and experiment with these circuits. Much thanks for that!

Great job with the explanations!!! Very detailed, Dave, and I'll be watching it again. THANK YOU!!

great video! please keep making more tutorials like this :)

Brilliant! No one can explain it better. Thank you so much for the lesson

So simple explained and understandable. Helped me a ton at measuring practice class. Thank you so much.

I was having a really hard time understanding opamps. Thank you for making my life easier!!

Great video Dave, thanks for all of the work you do!

You are single handedly getting me through my digital electronics class!!

Best explanation on ALL of youtube. This was incredibly helpful. You have earned my subscription!

Hello sir and thank you for your very informative videos.
I have a question for you: I would like to make a circuit that can give me a rectangular signal between 0V and 5 V. A kind of switch, but with a smaller rise time in the order of 50ns to 100ns.
I tried with the Mosfets, but the output siganl to a lot of swings and noises.
What you can advise me or have already made a circuit like that.
I like to test the filters placed at the retraction of a microcontroller by placing this signal recregular and read the response of the filter.
Thank you

Thanks to this video I got 97% to my circuit's homework!! :D Thanks a lot, you are a great teacher :)

Thanks a lot for this vid, Dave. I'm in Basic Circuits now, and your explication is notably better than most others.

Excellent video Dave!
Concerning the puzzle on the end. I think it's the reduced current sinking capabilities of the LM358 when Vout is small in respect to ground. If look up the "Output Characteristics Current Sinking" graph in the datasheet you can see that the LM358 can sink very little current at low output voltages. As you have a 1k R1 and 2Vpp input voltage you have 2mApp of current, which is still too much to sink for the LM358 at low output voltages. So the LM358 can't keep the virtual ground equal with the "real" ground trough it's FB network. Therefore you get those spikes and the sagging and rising of the virtual ground in between.

Thanks to you, and your videos I am today a successful engineer working in semiconductor industry. I am just coming back, years after I watched this video for the first time. I was having problems passing the only one remaining subject to get my degree and was searching for a helpful video on opamps. Not only you helped me, but also inspired me with your positive personality! Keep up the good work!

Majestic explanation. I'm always amazed how things can become clear after your videos. Unbelievable.

You helped me realize things in a practical way. Thank you very much. If possible kindly explain the ADC and DAC operation in depth please.

Most valuable video ever! Thank you, Dave! Respect for your hobby (work)!!!

Excellent discussion. Takes me back 35 years to my intro to op-amps. My professor explained what was to us an amazing and confusion subject just as you did and within a day or so we couldn't wait for the lab. I'm now hooked on your channel. atb Opal

Thanks for such a clear explanation regarding OpAmps! It's a component I see on a lot of schematics and in a lot of other TheXvid videos, but I cannot see how and why it's included.

I am deeply grateful for your wonderfully simple explanation of OpAmps.
I love your enthusiasm and ability to "dumb it down". it's obvious you LOVE your subject! If only every teacher was as good as you! THANK YOU FOR YOUR EFFORT Dave, and I LOVE your tee-shirt! :-).

Thank you for this very educational video!
Are op-amps a good way to make the meter of an analog instrument more sensitive to signal ??
If yes, have a very specific situation where I'd like to apply an op-amp:
I have installed a shunted ammeter in my car to monitor how my alternator charges the battery, or when the battery is being discharged by various loads when the engine is off. The ammeter gauge reads up to 150A (scale goes from -150A to +150A) and is mounted on the dash. The ammeter shunt (150A 50mV) is external, being mounted behind the firewall. Two fused sense leads go from the shunt, through the firewall, to the dash ammeter gauge. It works well and I chosed a 150A ammeter because the alternator is rated 91A (at 5100rpm) and I know it's better not to use shunt to current more than 2/3 their ratings because they could get hot and possibly loose their calibration. But in normal situations, I never see more than + 20-35A right after I start the car (alternator charging battery), and after a few minutes the needle is close to 5-10 Amps (battery almost completely replenished by the alternator, not taking much charge anymore). So the thing is that each graduation on the ammeter gauge are 30A (not very precise). I'd like to be able to press a momentary switch (mounted on the dash) to increase the sensitivity of the ammeter gauge by a factor x5 (meaning when the current is 30A, the meter could display 150A). The shunt is rated for a 50mV voltage drop through the sense leads when the current is 150A. So at 30A, the voltage drop is 10mV. So basically, I'm looking for a small circuit (op-amp based?) that would linearly increase a 0-50mV signal to a 0-250mV one. I'm okay with 5-10% reading accuracy. I thought maybe I could find some suitable amplification circuit on amazon to do this job. Can you recommend anything ? I found something called a "AD620 Gain Signal Amplification Module", but I'm not sure if this is adequate. Any recommendation ?
I do not want to install a smaller shunt instead of the 150A one. There was one instance in the past where the ammeter read close to 80A (I had jump started my car but my battery was completely dead at 0V). So I don't want to risk using a 30 or 50A shunt.

Wow - this is gold.... thanks for your time, very good explanation and very very useful! And here was me thinking op amps just amplify signals.... how wrong was I?!

Thanks for taking the time to do this... I'm learning electronics on my own and this really helps...

way to go buddy! I pay 3 grand in course fees a semester and you just explained it better then my professor could in 8 weeks so far. THANKS! keep at it.

Great video. I've been reading about Op Amps all day and not fully getting it. This crystallized everything I've read into something I can understand. Thanks!

Great video. Would love to let you know that MANY people like myself appreciate and love your content! Keep rocking!

One of your best tutorials for me. Thanks Dave!

AS ALWAYS, EXCELLENT Tutorials, and Reviews by EEVblog. GREAT TALENT to FOCUS in the ESSENTIALS, and in the Key CORE CONCEPTS of the Electronics in questions, without COMPLICATED "ANATOMY" AND "PHISIOLOGICAL" Explanations as MOST of the Electronics Textbooks and TheXvid Presentations do ! NO EXTRA AND UN-NECESSARY HEAVY WEIGHT AND LUGGAGE !

Dude, I hope you make good money an enjoy your job. Your videos are awesome. One of my main resources. With school being so crazy, expensive (and poorly taught). Really makes one appreciate your efforts here even more. So thanks again, keep teachin'!

Your explanation is so lucid. Thank you Sir! 😊 Will come to yaa videos for more good understanding

I wish I’d had this video years ago in engineering school! Thanks, Dave.

unbelievable, what a master class. this teacher deserves his salary. I honestly want to make a donation. you made my day. I never laughed so much in class as I did in this video with you!! :)) he does not only explain it amazingly well, but also makes it entertaining. 10 points

Thanks for the excellent video. Having had no clue about OpAmps before, it just helped me to figure out how to drive an LED from a 1.5V battery powered DCF77 receiver with a 5V powered LM358: One half as buffer, second half as a noninverting amplifier.

I love the way how he turn such a topic to an interesting one....he is a great teacher

Hi dave, your efforts are appreciated. I want to know can I use the op-amp in buffer state to measure the open circuit voltage of PV panel without disconnecting the load. Thanks.

Did you ever make a video on op amp limitations? I think it would be very useful.

Ohmygosh, is that really it? You just compressed my college circuits II class into a 50 minute video! Thanks for the simplification!

You are awesome, as usual Dave. I had only one great electronics instructor, back then...the rest were crap!

Wow, huge thanks for a crystal clear explaination! I have watched several other videos where others tried to show how awesome opamps are and after those videos I became more confused. At last, thanks to your awesome video I understand what it is and how I can use them. Awesome Dave, it´s like christmas following your videos.

You are an amazing teacher! Thank you!

Thanks Dave. I watched this as a refresher for an Engineer II technical interview. They asked all Op Amp questions! Passed it!

Congrats! You were able to explain Amp Ops in a very fun, easy, didatic way! Very Impressive. Prof. Newton

OMG this's easy to understand more than many other videos. Thank you a lot

Interestingly I just recently recommended someone to look into using an opamp for their project...
@EEVblog never disappoints.

You just made studying electronics much easier, thanks!

I do realize this is a pretty old video. But you gave an extremely great explanation of op-amps for sure. Bravo sir, Bravo...

very good tutorial, you explained many things I've found in circuits an now I can
understand much better.

If my college lecturer in the 1970s in England had been just half as good as explaining things as you, I could have saved myself 40 years of stress thinking that I was an idiot. Keep up the excellent work, you obviously love passing on your knowledge and are brilliant at doing it. I am now totaly gripped.

The concept of virtual ground was delivered precisely.
Thank you Dave!!!!

Great video - I supposedly learned op-amps two-decades ago but never got them until now. Thanks

i first watched this video in my first year, it has been five years now, but i still come to this video when i need a recap in this topic... yes, he is that good at explaining electronics stuffs!

as usual extremely well explained! Thanks a lot :)

Hey by the way great explanation but what will occur when we add a active component in the feedback rather than a passive one what will be the overall effect on the gain and other parameters.

tonight i learned 10x more about op-amps, and with a deeper understanding, than
i did in a whole semester in a suffocating classroom. Thank you for your time.

Thank you! You are great! But when I tried both of input types, I didn't get amplification to my audio signal.
Vcc = 5V
RF = 100
R1 = 10K
So why didn't I get 101V gain?