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.
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.
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!
electronic technicians nowdays repair FLAT TVs, monitors, cell phones, install and repair satellite installations, alarm systems, fire detection systems, CCTV installation, PLC programming and maintenance in industrial applications, and a variety of other applications ... Nowadays, even the electrical appliances of a hotel kitchen may have electronic control boards with fiber optic and internet connectivity. And in some countries it is not always "throw the old board away and put the new one" this is the easy way that even a 10 yo child can do. What if a new electronic board is too expensive ?
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!
This is my new favorite UA-cam 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!!!
Most excellent basic introduction to op-amps I know of. It tells you everything you need to know about fundamental operations of op-amps to get you on your way to understanding more complex circuits.
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.
I wish we had the time for that... I'm in my second year and we spent two days on op amps. This video helped me quite a bit. I guess we'll return to the op amps later on..
@@TheDaniel85 I am in my junior year, If anything interesting starts, it's going to be in 3rd, 4th year. First two years is just a dull foundation, during a third year pieces of puzzle will be coming together.
It's so great to see fellow Australians showing up on UA-cam. Especially for something like explaining electricity. Bringing fame and reputation to our country!
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 :)
Amazing how simple the above is when you can assume that the internal gain of the opamp is infinite. Everyone going through EE should be able to demonstrate the above in the time it takes to write it down. Well done.
+Kenneth Tan blew my mind when I finally figured out why they use a buffer on an inverting op-amp. It's the simple things that others take for granted. These videos are chucked full of informational tid bits one should store away my understanding of circuit design is getting better with each eevblog
+RRClassicman This is true fact about formal education, mostly in schools you learn almost nothing! That is situacion in Croatia, just a lot of unnecessary material with zero interactivity with the student
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!
Your video is gold. I modeled both inv amp and non-inv amp in LTspice with MAX4352 op-amp. Input voltage: [0,0.5] volts. Vcc:+5v, Vee: GND. Worked perfect. Thanks for your work!
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.
You are right, just a small clarification. the OA at 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.
+TheElectr0nicus but why does it jump like that? And why is there such a weird knee in the sink around that voltage (i.e. the physical reason for the fact that it goes closer to linear at even lower voltages)
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
Never gave money to a UA-camr ever, until now. Started this hobby six months ago. Tried to make a little lab myself but made mistakes. Then I watched your video on how to start an electronics lab. Followed your advice and now everything is set up and working perfectly. makes it so much easier! My learning curve has advanced leaps and bounds. Cant thank you enough.
Great explanations. I used OpAmps before, but more copy-and-paste style, just using the standard circuits without thinking about it. Now it makes sense why it works, and with the two rules I might even create equations to analyze more complex circuits, like the differential amplifier, where you've lost me a bit.
I'm not sure what the issue is. Analyze it like any other inverting amp. The voltage at the inverting input sets the voltage at the non-inverting input: 0.91091V. The voltage drop through the inverting R1 1K resistor is 1.1V - 0.91091V, or 0.1909V. The current through the inverting R1 and sunk by this inverting op amp through the feedback circuit is 0.19091V / 1K, or 0.1909 mA. The voltage drop across the feedback resistor R2 is 0.1909 mA x 10K, or 1.9V. The voltage at the op-amp's output is the voltage at the inverting input less the voltage drop of the feedback resistor, R2: 0.9191V - 1.9V, or about -1V. As a check. the voltage gain formula is -R2/R1, or -10K/1K = -10. The difference in voltage at the inverting and non-inverting inputs is 0.1V. So, the op-amp's output using the gain formula is .1V X -10, or -1V.
Back in May of 1978 I started work at an aerospace company that made the engine controllers for a military jet aircraft. The engine controller was a low frequency (less than 10 KHz) precision analogue computer that had amplifier gains & offsets calibrated to +/- 2 mV with select on test 1% tolerance resistors. Some critical circuits in the controller used 0.1% tolerance resistors. Positive 10 V and negative 10 V references were used throughout, and as well as the usual feedback loop components there were two 10.6 V Zener diodes in each loop. All of the virtual earths were connected to a virtual earth monitor that used a high gain amplifier to indicate any opamp failures. After a few years the engine controller was redesigned around 12 MHz 16 bit microprocessors and was considered to be not as good as the analogue version because at full speed the aircraft would travel about 50 feet before the software loop was reiterated. Some of the circuitry in the analogue version was very unusual and complex and I learned a lot about circuit design with opamps. It was a great place to work because there were occasions when batches of high grade components were thrown into a skip, and the company didn't care where they went. To this day I have a huge stock of mostly obsolete but still useful components that I use for making projects and stuff that can't be purchased off the shelf. Thanks for the video.
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.
We're moving into Op-Amps in my 2nd year circuits class, and I've already gone through 3 shorter "intro to op amps / op amp basics" videos with high view counts and all of them were rubbish in terms of being "basic introductions". This 50 minute video is already vastly superior in presenting the fundamentals clearly and simply in the first 5 minutes. Happy to have found it!
Hey Dave, can your next video be on the stuff you crossed out? I wanted to cry there for a sec. There are tons and tons of resources about the basics of op amps, there a dime a dozen. However, there are very very few complete videos on op amp internals. Finding videos on the basics is utterly simple but finding well presented videos on more advance material such as op amp internals is painfully difficult.
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.
Dave, though i've never met you or even had a two-way communication with you i do see you as my friend and tutor. Maybe it's simply because you come across as a really nice guy in your vblog, and i've seen so much of your face and so much appreciate your educational skills. Maybe it's becuse with you as my major source of education i've had the best grades in every course i've taken over the last 18 months, spending close to no time at all studying, giving me time to earn some well needed cash for equipment, working as a private tutor for other students, and that was not even deliberate. I was approached by peers who wanted tutoring and insisted on paying me for it, reasoning that their parents were prepared to pay the tripple amount to an actual professor who would no likely be any better than any of our own teachers, working out of the same curriculum, and that they knew from class that they understood me way better than any teacher. Because every teacher we've ever had can take hours trying to explain these concepts to no avail, but using sometimes slightly modified (just enough to fit exactly the concept we're studying and the specific questions the sometimes slighly slow teacher wants answered at that moment) versions of what you've taught me i can explain concepts so that my peers understand them well enough to get at least a C in a matter of a few sentences. No matter what knowledge gaps my teachers have left behind i can fill them in, in a matter of minutes and almost never having to explain something twice to anyone, ever, using your pedagogic models! 9/10 times when i explain something the answer is something like "Ahaaa! Oh my god i feel so dumb, it's not even that complicated!" A lot of people don't appeciate the fact that the ability to understand something better than others, doesn't magically give you the ability to describe it in a way so that those that don't understand it can also do so! It's not just that i have complete confidence in the quality of the information you provide, it's your ability to explain thing that would have taken me hours or days to figure out, if at all, in a matter of seconds or minutes. In fact the service you provide me, absolutely for free, saves me so much time (generally in between 10-20 hours a week in school. Is this even real?!!!!! o____0 ) since i don't have to study anymore to get top grades and not be the teacher's pet but rather his assistant! So... The fact of the matter Dave, is that i basically owe you roughly 17% of my total spare time, weekends included! Those are 17% of the part of my life that i get to spend as my heart desires. And i simply just can't thank you for that in writing, because whatever words i chose would be an insult to your genius! But still, i do have to say something so a simpler thank you will have to suffice. Thank you professor Dave, thank you so very very much! The quality of the service you provide is in my experience unprecedented in any and all forums from the web to actual traditional education in a "real" school. I hope that you love doing what you're doing as much as i love watching you do it, and that you will keep doing this for a long, long time! Your devoted fan and pupil, Fredrik Sjöblom, Stockholm, Sweden.
Great explanation, you just took the best OP-Amp explanation until now from:YT- John Santiago Op Amp Design Basics - Inverting Amplifier - Part 3 (i was actually wondering when you will do that 8-). While you mentioned ohm's law you might add Kirchhoff circuit law in the part where you "wonder" about where current goes and that lack of minus in inv. OP gain formula was bugging me until you corrected it... For the end, you put smaller resistor which drives 10x larger current form output trough feedback resistor to "match/counter" input current (100uAmpsp rise into 1mAp) so output stage switches into B class (whole chip with 2xOPAmps has less then 1mA quiescent current and output stage probably uses about 70% of that) and you see clear crossover distortion on the output waveform (where OP-Amp loses control hence the spikes on the input, you can represent that as vehicle steering wheel dead play for mechanical types) Great video, just took best opamp explanation title,cant wait for #2,3,....
What the hell just happened? I felt like I had watched a 10 min video. By the time I looked at the time line, 49 minutes had already passed. Magic OOOOoooooo. XD
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!
And now we need a second part, where you show us the non-common circuits, as let say...Gyrator-stuff, Log-converters, average/peak rectifiers, and "interferences" when using OpAmps in RF circuits (like input pin reversion)....;)
Bipolar transistor explanation: The base-emitter junction behaves like a diode. In NPN transistors, it goes from base to emitter, and in PNP transistors, it goes from emitter to base. The current flowing between the emitter and the collector is limited to some gain (>100 for small-signal transistors, 20-100 for power transistors) times the base-emitter current. This current is only allowed in one direction (from collector to emitter in NPN transistors, from emitter to collector in PNP transistors). Field-effect transistor explanation: ¯\_(ツ)_/¯
Whatever haven't tought for x amount of reasons eg lack of access to higher education, means of funds, have a chance to broaden my knowledge and horizons thanks to you and a few other persons like you. A huge thank you is certainly not enough.
That's because he has designed so much own circuits Was a professional electronic designer Invented 32 channel logic analyser in the 80s Played with lot of op amps and some professors have never used a 741
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!
thanks for clarifying the 'comparitor' funcionality, where rule 2 doesn't apply in the open-loop condition. most other resources seem to neglect to mention this, but it was very helpful to finally lay this doubt to rest. cheers
The teachers have to include all of the unnecessary theory involved as if there is no IC, but we can't repair the IC, only replace it and you're starting from scratch which is not needed unless you plan to make your own IC and half of these teachers speak in monotone and barely grasp what they're reading so when you ask certain questions they will look it up and attempt to explain, but there are the exceptional that really know and they have a way to explain because they have the full understanding.
This is a great video for some simple applications of op-amps and beginners. However, more complex theories are necessary for deep understanding of the real processes, especially if you are a device developer, rather than simply service officer.
Do you have a t-shirt for every electronics component? :D But seriously, thumbs up for the simple and straight-to-the-point explanations. I am a programmer who sometimes has to deal with electronics. If I take some classical electronics book, it is all over with formulas, math and what not, when all I actually need is just basic understanding how to build or troubleshoot some circuit. The same problem goes also with mathematicians. For example, on some forum I asked how to use some specific function from a really popular FFT library to calculate coefficients for FIR filter, and math gurus threw lots of formulas on me and no-one could tell me that I need just two code lines to correctly feed FFT data and then add an offset. I spent two days with Matlab to find out that I needed that damned offset to get the right data out, and no-one could tell me such a basic thing! So thanks again for your work to make things simple for us, beginners and hobbyists.
I remember learning about op amps in college. They were the most amazing thing. Built a “temporary” audio distribution amp for a radio station till they could order one. Ten years later after running 24/7 they replaced the mixing board and got rid of it. It was a LM 324. Probably spent $15 on parts.
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
Not only You would :) As I have financial profit from becoming a better designer by watching this blog it seems reasonable to pay for more tutorials of this quality.
Hi there! First of all I would like to say that this video was probably the most clear explanation I ever had. This is the reason I am asking here instead of a forum.Next is my problem. I am trying to interact a thermocouple K - type. So I try to gain about 1mv ppv to 5 volts on the adc. I tryed the simple shifting op amp from the video, I tried as well the inverting op amp for the negative temperatures range where I get 0.5 volts for positive temperatures. Both of them the cold end was grounded. The most successful try was for a differential op amp where after dividing the output by the gain I get triple value (2.1mv instead of 0.07mv) . Could this be caused from the reason I have no buffer, or maybe the lm358 is not a rail to rail (even if data sheet says they are for the low range)
nevermind I found it: "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."
@@KingJellyfishII Above explanation said. at Vout = -0.5V I sink = 50uA (> 30uA) Can you please explain me, What special thing happens at -0.5 V, Which doesn't happens at other output voltages. Because, At higher voltages on the non inverting input, Expected Sink current is higher than that at 0.5 V output.
Thank you for the great tutorial. Does anyone know what are the advantages of a buffer - why do we use them. Do you know any good practical examples. Thanks.
We use print buffers to let the 3D design tool to go back to doing anything else but micromanaging the 3D print job while the 3D project is being extruded. So I guess 3D is the droid u were looking for.
Love this video, likely the best, thorough explanation of an op amp...however. It would be awesome to see the breakdown of an op amp in a device. How it's connected, controlled, what's it connected to and how is it controlled. Is it in a radio, TV, flashlight, calculator, motor controller, vacuum...whatever. I have seen dozens of great videos, all explaing the comparator function and many other functions, how the op amp works, how a resistor can manipulate the outputs regulating voltage...but hardly any real world applications with them in use, and how they are either controlling the output device or another component in the circuit like a transistor. One example would be, instead of many videos stating the 4 cycles of a modern engine, like fuel being sprayed into the engine, intake, compression, power, exhaust, talk about how the opening of the throttle body causes more air to enter and the mass airflow meter sends a signal to the PCM to command more fuel, then the O2 sensor fine tuning the mix, somewhat in depth like that. An op amp gets explained that the output keeps the input the same....but that's in dozens of videos. Going over an op amp in a device and describing how each part of the circuit controls and affects the op amp would be the visual that ties this together for beginners. Sorry for the long rant, this is still the best video and I applaudball your efforts in teaching others!
They say the most intelligent people can explain something complex very easily. I've now fully understand the electronic OPAMPs operation, thanks to you ;-)
Ok Ill have to re watch this. I was doing dishes and cooking super when I watched most the first time around lol! So much information available here and Im sure he is better than alot of college teachers.
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
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.
it didn't get lost in the comments!!!!!!
@@不知所错 We're all lost my friend.
I totally agree dude…. we’re so fortunate to have people like this dude
Came up as the first comment... 🙂 The mysterious ways of the youtube algorithm will never be comprehensible for us "ordinary people" 😎
This guy is DATA from Startrek ];-D.
Nine years later, this is still the best and most understandable intro to Op Amps ever.
one of the very best
Fully agree!
In my whole electronics major shit , I have never seen a person who explains virtual ground like this.
#RESPECT
This term makes no sense
@@StEvUgnIn Abolutely no sense.
He’s amazing love it,,I’ll figure it out virtual ground oupps
It’s spiritual
@@StEvUgnIn Does the "virtual ground" means 0V ?? If so then it really doesn't make any sense 🤦♂️🤦♂️
Eight years later, this is still the best and most understandable intro to Op Amps ever.
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.
Mirko Mueller it's also great to see someone enthusiastic about what he does.
Mirko Mueller So are you enthralled?
A good teacher.
48:40
Can anybody please tell me the reason of this ?
5.300 students are very grateful you uploaded this video
+95berre count me in!
You can't have 5.3 students.
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!
I had electronics like a hobby in the secondary school and also the time I was in the university even I've studied mechanics. Great presentation !!
electronic technicians nowdays repair FLAT TVs, monitors, cell phones, install and repair satellite installations, alarm systems, fire detection systems, CCTV installation, PLC programming and maintenance in industrial applications, and a variety of other applications ...
Nowadays, even the electrical appliances of a hotel kitchen may have electronic control boards with fiber optic and internet connectivity.
And in some countries it is not always "throw the old board away and put the new one"
this is the easy way that even a 10 yo child can do.
What if a new electronic board is too expensive ?
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!
The fact we can learn this and not have to go into debt... your a gift to engineering Dave!
Forget the debt. Being water boarded everyday is not what i would call learning.
@@kevin42 agreed and they inject way too much to do with political issues at times to
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!
48:40
Can anybody please tell me the reason of this ?
This is my new favorite UA-cam 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!!!
7 years on and your videos are still helping new technicians. I really appreciate this, thank you.
FINALLY!!!! A video that ACTUALLY EXPLAINS HOW IT WORKS!!!!!
Dave, this video was a godsend.
Most excellent basic introduction to op-amps I know of. It tells you everything you need to know about fundamental operations of op-amps to get you on your way to understanding more complex circuits.
Thumbs-up for the vid on properly terminating op-amps please Dave ;)
i agree too!
e2e.ti.com/blogs_/archives/b/thesignal/archive/2012/11/27/the-unused-op-amp-what-to-do - found this today on TI's website
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.
I wish we had the time for that... I'm in my second year and we spent two days on op amps. This video helped me quite a bit.
I guess we'll return to the op amps later on..
@@TheDaniel85 I am in my junior year, If anything interesting starts, it's going to be in 3rd, 4th year. First two years is just a dull foundation, during a third year pieces of puzzle will be coming together.
It's so great to see fellow Australians showing up on UA-cam. Especially for something like explaining electricity. Bringing fame and reputation to our country!
COMPARED TO THE USA, Y'ALL DID NUTTIN SEE---
Some people really got the "art of sincere teaching". This is the best I've seen so far regarding Op amp basics. God bless you Sir.
One of the most sensible ways of explaining the basics of op amps. Great work Dave
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
:)
Amazing how simple the above is when you can assume that the internal gain of the opamp is infinite. Everyone going through EE should be able to demonstrate the above in the time it takes to write it down. Well done.
Here Vin1=Vin2 due to the virtual short between the input terminals, if anyone had a doubt
Thank you so much for this! Not as bad as I thought coming into this! Matter-in-fact, really fun!!!!!!!!!!!! :DDDDDDDDDDD ♡
I Learned more in 10 min of your video than 1 month of my Power Control Electronics class. Thank you!!!!!
+RRClassicman Glad to hear! (well, kinda...)
+RRClassicman Well 50 minutes in my case. It changed my biased "OMG an OpAmp" to "OpAmps, I love'em"
+Kenneth Tan blew my mind when I finally figured out why they use a buffer on an inverting op-amp. It's the simple things that others take for granted. These videos are chucked full of informational tid bits one should store away
my understanding of circuit design is getting better with each eevblog
+RRClassicman This is true fact about formal education, mostly in schools you learn almost nothing! That is situacion in Croatia, just a lot of unnecessary material with zero interactivity with the student
+Blade Runner Well, in a UA-cam video, there's also 0 interactivity with the student ;) Other than that, you're 100% right.
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!
You have left a legacy on UA-cam for the coming generations. You are immortal. Salutes.
Your video is gold. I modeled both inv amp and non-inv amp in LTspice with MAX4352 op-amp. Input voltage: [0,0.5] volts. Vcc:+5v, Vee: GND. Worked perfect. Thanks for your work!
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.
Nice work! I noticed that all datasheets doesnt show this. The Motorola version did not so that might be an extra "trap for young players"
That´s it, exatcly :)
You are right, just a small clarification. the OA at 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.
+TheElectr0nicus but why does it jump like that? And why is there such a weird knee in the sink around that voltage (i.e. the physical reason for the fact that it goes closer to linear at even lower voltages)
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
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
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 !
Never gave money to a UA-camr ever, until now. Started this hobby six months ago. Tried to make a little lab myself but made mistakes. Then I watched your video on how to start an electronics lab. Followed your advice and now everything is set up and working perfectly. makes it so much easier! My learning curve has advanced leaps and bounds. Cant thank you enough.
The concept of virtual ground was delivered precisely.
Thank you Dave!!!!
yep. he nailed it
Great explanations. I used OpAmps before, but more copy-and-paste style, just using the standard circuits without thinking about it. Now it makes sense why it works, and with the two rules I might even create equations to analyze more complex circuits, like the differential amplifier, where you've lost me a bit.
Yeah, I did gloss over the differential amplifier a bit, sorry about that.
Gloss? Yeah I totally missed Diff Amp totally. You probably used initials DA and it just didn't register in my mind.
I'm not sure what the issue is. Analyze it like any other inverting amp. The voltage at the inverting input sets the voltage at the non-inverting input: 0.91091V. The voltage drop through the inverting R1 1K resistor is 1.1V - 0.91091V, or 0.1909V. The current through the inverting R1 and sunk by this inverting op amp through the feedback circuit is 0.19091V / 1K, or 0.1909 mA. The voltage drop across the feedback resistor R2 is 0.1909 mA x 10K, or 1.9V. The voltage at the op-amp's output is the voltage at the inverting input less the voltage drop of the feedback resistor, R2: 0.9191V - 1.9V, or about -1V. As a check. the voltage gain formula is -R2/R1, or -10K/1K = -10. The difference in voltage at the inverting and non-inverting inputs is 0.1V. So, the op-amp's output using the gain formula is .1V X -10, or -1V.
Hi Dave,
Please do a video on how to terminate OP-AMP, it's an important topic as well.
Good job, thank you.
I have been watching this as a kid and now it feels so nostalgic after i have passed my electronics engineering school , it really so nostalgic
This explanation is superb! It is THE best I've ever seen from any book or professor. Truly, a gold nugget.
Yeah!
perfect explanation about virtual ground.
Thanks Dave!
Patrick Franco Bello Thanks, glad you liked it.
@@EEVblog Thanks
Back in May of 1978 I started work at an aerospace company that made the engine controllers for a military jet aircraft. The engine controller was a low frequency (less than 10 KHz) precision analogue computer that had amplifier gains & offsets calibrated to +/- 2 mV with select on test 1% tolerance resistors. Some critical circuits in the controller used 0.1% tolerance resistors. Positive 10 V and negative 10 V references were used throughout, and as well as the usual feedback loop components there were two 10.6 V Zener diodes in each loop. All of the virtual earths were connected to a virtual earth monitor that used a high gain amplifier to indicate any opamp failures. After a few years the engine controller was redesigned around 12 MHz 16 bit microprocessors and was considered to be not as good as the analogue version because at full speed the aircraft would travel about 50 feet before the software loop was reiterated.
Some of the circuitry in the analogue version was very unusual and complex and I learned a lot about circuit design with opamps. It was a great place to work because there were occasions when batches of high grade components were thrown into a skip, and the company didn't care where they went. To this day I have a huge stock of mostly obsolete but still useful components that I use for making projects and stuff that can't be purchased off the shelf.
Thanks for the video.
so was the processor just running at too low frequency? also what did the engine controller do/was used for?
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.
We're moving into Op-Amps in my 2nd year circuits class, and I've already gone through 3 shorter "intro to op amps / op amp basics" videos with high view counts and all of them were rubbish in terms of being "basic introductions". This 50 minute video is already vastly superior in presenting the fundamentals clearly and simply in the first 5 minutes. Happy to have found it!
Hey Dave, can your next video be on the stuff you crossed out? I wanted to cry there for a sec. There are tons and tons of resources about the basics of op amps, there a dime a dozen. However, there are very very few complete videos on op amp internals. Finding videos on the basics is utterly simple but finding well presented videos on more advance material such as op amp internals is painfully difficult.
Agreed! It (almost) always helps, after learning the basics, to learn how they physically work inside to really cement the concepts in your brain!
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.
i always catch myself smiling while watching this guy
Dave, though i've never met you or even had a two-way communication with you i do see you as my friend and tutor. Maybe it's simply because you come across as a really nice guy in your vblog, and i've seen so much of your face and so much appreciate your educational skills. Maybe it's becuse with you as my major source of education i've had the best grades in every course i've taken over the last 18 months, spending close to no time at all studying, giving me time to earn some well needed cash for equipment, working as a private tutor for other students, and that was not even deliberate. I was approached by peers who wanted tutoring and insisted on paying me for it, reasoning that their parents were prepared to pay the tripple amount to an actual professor who would no likely be any better than any of our own teachers, working out of the same curriculum, and that they knew from class that they understood me way better than any teacher.
Because every teacher we've ever had can take hours trying to explain these concepts to no avail, but using sometimes slightly modified (just enough to fit exactly the concept we're studying and the specific questions the sometimes slighly slow teacher wants answered at that moment) versions of what you've taught me i can explain concepts so that my peers understand them well enough to get at least a C in a matter of a few sentences. No matter what knowledge gaps my teachers have left behind i can fill them in, in a matter of minutes and almost never having to explain something twice to anyone, ever, using your pedagogic models! 9/10 times when i explain something the answer is something like "Ahaaa! Oh my god i feel so dumb, it's not even that complicated!"
A lot of people don't appeciate the fact that the ability to understand something better than others, doesn't magically give you the ability to describe it in a way so that those that don't understand it can also do so! It's not just that i have complete confidence in the quality of the information you provide, it's your ability to explain thing that would have taken me hours or days to figure out, if at all, in a matter of seconds or minutes. In fact the service you provide me, absolutely for free, saves me so much time (generally in between 10-20 hours a week in school. Is this even real?!!!!! o____0 ) since i don't have to study anymore to get top grades and not be the teacher's pet but rather his assistant! So... The fact of the matter Dave, is that i basically owe you roughly 17% of my total spare time, weekends included! Those are 17% of the part of my life that i get to spend as my heart desires. And i simply just can't thank you for that in writing, because whatever words i chose would be an insult to your genius! But still, i do have to say something so a simpler thank you will have to suffice.
Thank you professor Dave, thank you so very very much! The quality of the service you provide is in my experience unprecedented in any and all forums from the web to actual traditional education in a "real" school. I hope that you love doing what you're doing as much as i love watching you do it, and that you will keep doing this for a long, long time!
Your devoted fan and pupil,
Fredrik Sjöblom,
Stockholm, Sweden.
This is probably the most comprehensive and effective explanation I've ever watched about opamps. You sir are a pedagogical genius!
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!
Great explanation, you just took the best OP-Amp explanation until now from:YT- John Santiago Op Amp Design Basics - Inverting Amplifier - Part 3
(i was actually wondering when you will do that 8-).
While you mentioned ohm's law you might add Kirchhoff circuit law in the part where you "wonder" about where current goes and that lack of minus in inv. OP gain formula was bugging me until you corrected it...
For the end, you put smaller resistor which drives 10x larger current form output trough feedback resistor to "match/counter" input current (100uAmpsp rise into 1mAp) so output stage switches into B class (whole chip with 2xOPAmps has less then 1mA quiescent current and output stage probably uses about 70% of that) and you see clear crossover distortion on the output waveform (where OP-Amp loses control hence the spikes on the input, you can represent that as vehicle steering wheel dead play for mechanical types)
Great video, just took best opamp explanation title,cant wait for #2,3,....
What the hell just happened? I felt like I had watched a 10 min video. By the time I looked at the time line, 49 minutes had already passed. Magic OOOOoooooo. XD
Dave Cad works for me! I'm getting more info from you than I received making my way to an AAS ET degree. Thanks so much!
Very intuitive and easy to understand. Best explanation of op-amps I could find on UA-cam. Thank you so much!
Well, I secured more marks than my friends in our exam just by watching this video 2 hour prior to my exam. Thanks Dave.
Happy 600th EEVBlog Dave!
You have succeeded where hours of instruction and study have failed: making me understand how opamps work. I am unable to express my gratitude.
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!
And now we need a second part, where you show us the non-common circuits, as let say...Gyrator-stuff, Log-converters, average/peak rectifiers, and "interferences" when using OpAmps in RF circuits (like input pin reversion)....;)
I wish you could do one like this for transistors!
Bipolar transistor explanation:
The base-emitter junction behaves like a diode. In NPN transistors, it goes from base to emitter, and in PNP transistors, it goes from emitter to base.
The current flowing between the emitter and the collector is limited to some gain (>100 for small-signal transistors, 20-100 for power transistors) times the base-emitter current. This current is only allowed in one direction (from collector to emitter in NPN transistors, from emitter to collector in PNP transistors).
Field-effect transistor explanation:
¯\_(ツ)_/¯
Transistors are even simpler
This was the Video that made me fall in love with electronics!
What an awesome tutorial !!
Whatever haven't tought for x amount of reasons eg lack of access to higher education, means of funds, have a chance to broaden my knowledge and horizons thanks to you and a few other persons like you. A huge thank you is certainly not enough.
He's always smiling, and sharing useful knowledge. EV and Rosman are my fav. channels.
For the love of Tesla, I was so friggin' nervous when you forgot the 'negative' of inverting gain!
The little bump in the wave form i believe is because there was a squiggly line in dave cad and it carried over...
You gotta zoom into the dave cad to see it.
This guy taught me what I couldn't understand in my class even after discussing with 3 professors😂😂
Same bro
I was just thinking the same thinking I wish my college professor explained it like this...or maybe I was just too hung over to understand :-)
That's because he has designed so much own circuits
Was a professional electronic designer
Invented 32 channel logic analyser in the 80s
Played with lot of op amps and some professors have never used a 741
Your professors probably don't understand it either, so tell them to watch this video ;)
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!
thanks for clarifying the 'comparitor' funcionality, where rule 2 doesn't apply in the open-loop condition. most other resources seem to neglect to mention this, but it was very helpful to finally lay this doubt to rest. cheers
i never even gain 10% of knowledge i got here on opamps from those electronic classes back then on the 741
excellent tutorial
Excellent teacher - one of a kind.
The teachers have to include all of the unnecessary theory involved as if there is no IC, but we can't repair the IC, only replace it and you're starting from scratch which is not needed unless you plan to make your own IC and half of these teachers speak in monotone and barely grasp what they're reading so when you ask certain questions they will look it up and attempt to explain, but there are the exceptional that really know and they have a way to explain because they have the full understanding.
Pun intended?
you should be teaching university. that was better than any of my professors ever thought it.
This is a great video for some simple applications of op-amps and beginners. However, more complex theories are necessary for deep understanding of the real processes, especially if you are a device developer, rather than simply service officer.
RogovAB Thumbs down to you, guy. Get fucked.
@excited box Guys, I did not tell about Dave's video. I meant that this information is not enough for university program, which is much more complex.
Do you have a t-shirt for every electronics component? :D
But seriously, thumbs up for the simple and straight-to-the-point explanations. I am a programmer who sometimes has to deal with electronics. If I take some classical electronics book, it is all over with formulas, math and what not, when all I actually need is just basic understanding how to build or troubleshoot some circuit. The same problem goes also with mathematicians. For example, on some forum I asked how to use some specific function from a really popular FFT library to calculate coefficients for FIR filter, and math gurus threw lots of formulas on me and no-one could tell me that I need just two code lines to correctly feed FFT data and then add an offset. I spent two days with Matlab to find out that I needed that damned offset to get the right data out, and no-one could tell me such a basic thing!
So thanks again for your work to make things simple for us, beginners and hobbyists.
I remember learning about op amps in college. They were the most amazing thing. Built a “temporary” audio distribution amp for a radio station till they could order one. Ten years later after running 24/7 they replaced the mixing board and got rid of it. It was a LM 324. Probably spent $15 on parts.
Dude, best explanation of opamps I've ever heard! My professor in college back in the day was an asshole, making this so complicated.
I'm 15 and i love to make electronic gadgets this is the thing that I realy wanted to know thank you for doing just the same.
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
This was incredibly helpful... As a non-EE major, having to take a Circuits class, God bless you!
How much is a license for DaveCAD?
@Chris KwakernaatKwakernaat straight up. Puts all other EDAs to shame, self-powering monster of a tool
arrrrr .... shiver me timbers ....
There she blows Jimlad............aarrrrr
I have watched this umpteen times. Best tutorial EVER. Thank you.
It's been years now since I wanted to have a good understanding of opamps and i guess i have it now!!! Thank you so much!
Much better explianed than my college professor! Wish this was made 1 year ago :/
great t-shirt besides explanation
Ohmygosh, is that really it? You just compressed my college circuits II class into a 50 minute video! Thanks for the simplification!
Nice Video. There was nothing new for me but it is nice to just sitt down, relaxe and listen to electronic stuff. Thanks.
Yay 600 videos !! :D
I believe it should be Av = -RF/R1 at 22:30 Right?
This is great !
I would pay for Videos of you explaining Stuff :)
Not only You would :) As I have financial profit from becoming a better designer by watching this blog it seems reasonable to pay for more tutorials of this quality.
I would also pay for more videos similar to this one. Any chance of doing a kickstarter where we can contribute for more lessons like this one?
Donations:
www.eevblog.com/donations/
6 years later, this video still holds up like a champ
THANK YOU FOR THIS VIDEO!! I could not wrap my head around this concept but after this video I understood it !!!
Hi there! First of all I would like to say that this video was probably the most clear explanation I ever had. This is the reason I am asking here instead of a forum.Next is my problem. I am trying to interact a thermocouple K - type. So I try to gain about 1mv ppv to 5 volts on the adc. I tryed the simple shifting op amp from the video, I tried as well the inverting op amp for the negative temperatures range where I get 0.5 volts for positive temperatures. Both of them the cold end was grounded. The most successful try was for a differential op amp where after dividing the output by the gain I get triple value (2.1mv instead of 0.07mv) . Could this be caused from the reason I have no buffer, or maybe the lm358 is not a rail to rail (even if data sheet says they are for the low range)
+Venera Radoslavova Do ask on the forum.
Thanks!
Watching this all over again in 2020 just because the lessons are worth remembering and refreshing.
Nice explanation. Opamps were a mystery back in college, but one youtube movie explains it very clearly.
So - "Why is it so?". Can anyone explain?
It's been three years...
nevermind I found it:
"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."
@@KingJellyfishII how can i thank you enough
@@ashishrocks93 lol I just copy/pasted it from someone else
@@KingJellyfishII
Above explanation said.
at Vout = -0.5V
I sink = 50uA (> 30uA)
Can you please explain me,
What special thing happens at -0.5 V,
Which doesn't happens at other output voltages.
Because,
At higher voltages on the non inverting input,
Expected Sink current is higher than that at 0.5 V output.
circuit prof. made me cry today for not understanding this. Thanks for your help, wish you were my professor :(
He gets the noble prize. Thanks learned more amp then even though power possibly. God bless. I must apply this great knowledge
Thank you for the great tutorial. Does anyone know what are the advantages of a buffer - why do we use them. Do you know any good practical examples. Thanks.
Optimize the Flux Capacitor
I could be wrong but I am pretty sure that buffers are used when you do not want to disturb the non-inverting input that you are measuring.
We use print buffers to let the 3D design tool to go back to doing anything else but micromanaging the 3D print job while the 3D project is being extruded. So I guess 3D is the droid u were looking for.
2 Thumbs-Up from me for sure.
On behalf of every each one of electronics students thank
You are saving my university career 🙏🙏🙏🙏
Great video - I supposedly learned op-amps two-decades ago but never got them until now. Thanks
Love this video, likely the best, thorough explanation of an op amp...however.
It would be awesome to see the breakdown of an op amp in a device. How it's connected, controlled, what's it connected to and how is it controlled. Is it in a radio, TV, flashlight, calculator, motor controller, vacuum...whatever. I have seen dozens of great videos, all explaing the comparator function and many other functions, how the op amp works, how a resistor can manipulate the outputs regulating voltage...but hardly any real world applications with them in use, and how they are either controlling the output device or another component in the circuit like a transistor.
One example would be, instead of many videos stating the 4 cycles of a modern engine, like fuel being sprayed into the engine, intake, compression, power, exhaust, talk about how the opening of the throttle body causes more air to enter and the mass airflow meter sends a signal to the PCM to command more fuel, then the O2 sensor fine tuning the mix, somewhat in depth like that.
An op amp gets explained that the output keeps the input the same....but that's in dozens of videos. Going over an op amp in a device and describing how each part of the circuit controls and affects the op amp would be the visual that ties this together for beginners.
Sorry for the long rant, this is still the best video and I applaudball your efforts in teaching others!
They say the most intelligent people can explain something complex very easily. I've now fully understand the electronic OPAMPs operation, thanks to you ;-)
Tremendous teaching ability. Goes to the basics so the learning sticks for ever.
Ok Ill have to re watch this. I was doing dishes and cooking super when I watched most the first time around lol! So much information available here and Im sure he is better than alot of college teachers.
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
Best possible explanation of Virtual Ground concept.
I need the hard way.. :(
ua-cam.com/video/U3BGOaiyjz8/v-deo.html
Saumyajit Roy THANK YOU!!!
Well this is not the hard way. More like mid way. It's still opamp model. I want transistor based.