How Op Amps Work - The Learning Circuit
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- เผยแพร่เมื่อ 27 เม.ย. 2024
- In this video, Karen presents and introduction of op-amps how various ways they can be used in circuits. At a basic level, op-amps are quite simple. They compare the voltages at their two outputs and use the difference in voltages to determine how the signal is amplified. The differential voltage at the inputs often needs to only be a few microvolts to generate an amplified signal. To be able to finely control the gain, a feedback loop must be created between the op amp’s output and one of the inputs. This loop usually contains a resistor and/or capacitor to have finer control of the gain. Check out this Intro to Op Amps episode to learn more about how op-amp works and a variety of its applications: bit.ly/3csQDmT
You can also check out DC to Daylight where Derek presents his take on different types of OpAmps and how they work: bit.ly/3HYidII
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Interested in OpAmps? Check out this fresh content from Derek's on the topic here: th-cam.com/video/kF1wGW-h4Y8/w-d-xo.html
16 years ago, When I had this class in College I DID think OpAmps appeared to generate power out of nothing (after seeing a dozen OpAmp circuits ommiting the external power supply it's easy to forget them), and I remember not being the only one of my classmates confused, so I appreciate the comment near the end!
I think because of labels like gain and amplifier we got this wrong idea. I have only recently come to the conclusion that the device is not the amplifier but that amplifier is something you make using the device. Even that could be wrong.
We must have had the same teacher :D
@@dukeatreidas9771 ikr?
I think of it more like a flood gate on a dam, a little signal can let go to the full flow, except you've got a channel back to the floodgate to close it back up a bit. (I learned plumbing and electrics more or less at the same time, I'm always falling back on water analogies,lol)
@@Telee_Pawt нет, это устройство именно усилитель !с очень большим коэфицентом усиления! Без обратной связи около миллиона!
The thing that finally got me to understand OpAmps was this:
In a normal circuit, if two nodes are connected with nothing between them they have the same voltage and current can flow freely between them.
OpAmps "break" that rule. The two inputs are a pseudo-node where the voltages are the same, BUT no current flows. If you introduce that into the math of circuits you get a really powerful tool that lets you do all of the things described here.
she explained the subject in mins what my professor couldnt in 40 hrs of university classes
😂
Then surely he wasn't a professor at all. A simple water flow example is also useful for opamp explanation.
Thats why most of indian engineers are unemployed, because of poor way of delivering concept and below standard faculty
@@sujoypaul1874 don't lose hope bro
You can learn everything on the Internet
@@SumitSingh-iz9pw core subjects nhi milte bhai,bas dukan chalri h sabki
I'm currently in a circuits class and this has got to be the best explanation of op amps I've ever seen. Thank you!
When I learned and found about the op amps, how they work, as this component was the solution to my problem I was having at that time, this thing opened up a huge window in my tiny hobbyist electronic world. In the beginning it almost feel like magic. You can make so many things after you understand this component. You finally start to understand the whole picture, how things work in the electronic world.
Perfectly explained refresher of op-amps. Just what I needed. Thank you!
Oh boy the infamous 741, haha. You can't imagine the headaches that this little guy gave me in EE. Almost all of my PCB's that had the 741 never worked properly, and my professores would say "Oh the Schematic is correct and the theory is ok, but the 741 does not work for this application". It is a very simple op amp for sure. Amazing video!
Considering how much trouble the research for this episode gave me, I think I can imagine the headache. Haha. Glad you liked it!
About a year ago, I was at Dave Fullagar's home, the inventer of the uA741, the first internally compensated operational amplifier. He's as humble and sharp as ever. I actually met him after he retired from Maxim Integrated Products (one of three original founders), where I worked for a couple of years. Interestingly, he was supposed to be a geotechnical engineer but changed while at the university.
Is it possible that your circuits would have worked with an op-amp that had rail-to-rail outputs, which some do but the 741 does not necessarily? You can get differences between nominally equivalent op-amps with the same type number but of different makes. I designed a circuit for lithium cell management that worked well with a TLC272 op-amp made by Texas Instruments but it malfunctioned with a TLC272 made by ST Microelectronics. It turned out that the Texas Instruments TLC272 has rail-to-rail outputs although they are not demanded by the component specification (but not forbidden either), and the STM TLC272 does not have rail-to-rail outputs although it does conform to the published specification.
Thankyou so much for the detailed and concise explaining!
After 3 hours of binge searching for proper info on op-amp deployment and the various typical uses, Ive finnaly found your video and can now get to work on my project.
A good overview. Showing the components, pin callouts per component, and the overall circuits are helpful for context that many presentations lack. A lot of ground was covered going thorough different types without getting too bogged down.
Karen, THANK YOU! I'm looking at a RADAR imaging circuit ala Gregory Charvat, and he is using on Quad Op amp chip in a couple of different ways. Your video helped me understand first was a simple amplifier, then an Active Low Pass Filter. SUPER helpful video! I learn so much watching you.
Holy thank you for explaining it this way, no other relatively short video explains where the voltage goes to depending on the input, just that it amplifies one signal or flips another.
I love to build things with OP-AMPs. Once I built my own PWM dimmer/speed controller consisting of a NE555, a UA741, a BUZ11 MOSFET, 7 resistors, 4 capacitors and a potentiometer.
I operate my self-made 12V LED light strips on this dimmer. I simply used cable ducts for the LED strips. I drilled holes for 5mm LEDs in the cable duct cover. On the inside of the cover I soldered the wiring strands and the corresponding LED series resistors.
In the stairwell I also have the same cable ducts with built-in LEDs just above the steps, which are switched using a self-made time switch with an OP-AMP and MOSFET. The time switch is controlled by a radar motion detector, which can also detect movements through walls.
Advantage of the radar motion detector: It reacts to everything that moves, as long as it is not too small. But moving a finger is enough... PIR motion detectors only react to objects that are warmer than the ambient temperature.
thank you for actually making op amps make sense this is the best video ive ever watched on youtube :D
This was actually non-sense. Are you from Australia?
@@mrpeterfrazier 🤣👍
Great to the point video, clean slides, a lot of information per time! However, there are two mistakes in the differential amp slide (around 6:20);
1) The two inputs are interchanged. For non saturated operation (i.e. no comparator) the feedback path must always be closed, i.e., inverting input must be connected in any way to the output,
2) The two inputs must not be tied together. As you explain, the opamp amplifies the voltage difference between both inputs and does everything at its output to keep the voltage difference at the inputs as small as possible. So, a short circuit between the inputs makes it impossible for the opamp to work.
Keep on with your good work!
Thanks thought i was going to lose my mind.
Great vintage Oscilloscope in the back. Excellent for warming up your lunch while working.
Or as a mechanic you can warm up your lunch on a 350 cu. In. small block LS3 corvette engine
Brilliant Explanation. The whole OpAmp summed up in the best possible way !
Thank you for taking the time to explain op amps.
My OpAmp story: LM358 is a super-common, low cost OpAmp that is absolutely abysmal as an audio amplifier. It's fine for some purposes, but not that one. On three occasions I have needed to build an audio amplifier circuit and LM358 was the only OpAmp I had in my drawer. After much circuit fiddling, datasheet reading, and internet searching, I've managed to build an LM358 based audio amplifier circuit that was "better than nothing." That was the best I have managed. One trip to eBay and three weeks later, 100 cheap (around 10 cents a piece, after shipping) TDA2822M OpAmps arrived from China. I'll never use LM358 for audio again.
Thanks Kare, it is a nice lesson. So much to still discuss on opamps. I like them very much, IMHO they facilitate the design and implementation in a lot of projects.
The best explanation of the basics of Op Amps I have ever seen...
Hands down, this is the best op-amp tutorial
Great video, it made so much EE come rushing back into my brain.
Probably the best explanation of op-amps I've seen so far. Thanks!
not quite
Great lecture Karen . But I guess I will have to attend this lecture a few times more . Subscribed 😀
Perfectly explained of op-amps. Just what I needed. Thank you for Perfectly explained
Very fast,short,brief introduction to OpAmp .For three years since 2017 , I never use/touch/fritzing/multisim-experiance in electronics. I stopped washhands reading electronics, many people started to use VR/AR/MR/XR to designed/demo the digital-electronics new technology ( Printed Electronics, small-palm-size FPGA ,XILINS/INTEL ,software-hardware programming beyond Arduino,Rasberry PI-4 . Suddenly a young lady replacing a young man in element 14 ? A new fresh starts .Good to see new face ! Karen keep it up .
Great video! I own a Boulder 500AE NOS amp and this was a terrific tutorial. It is an op amp.
Great video, many thanks. And now a How OpAmps Work part 2 followup, please.
Well done! clear and concise overview of op-amps.
This is the best video I've ever seen for op-amps srsly
Hey, this was a well done video and a great presenter as well! No droning on about unless info and directly to the point. And, several schematics of uses of op-amps and what they are used for. This was great! Thanks!!
oh my, i feel like i have been hit over the head with a shovel. I think i need to watch this over again about another 100 times,
first time round i'm sure my brain thought it was in Japanese, oh i'm getting old :o)
I only watched it once, but paused it about 30 times!
It's a bit like being in a lecture where you are totally new to the subject and the teacher has no memory or comprehension of what it's like not to understand what it is she is teaching. The hit over the head with a shovel analogy is spot on. Thankfully there are much better teachers out there.
I had to learn these from a book. Enjoy!
@@WistrelChianti Some people learn differently. I found this to be the most concise and informative explanations I've found so far after a few videos.
@ggg666 >True that! I am just a retired auto tech. I figured an app Amp is used to make a “Low Fuel” lamp controller.
I would have watch this a lot to get my brain around it.
ASE Master Tech since 1978
Very nice introduction, 7:22 the inverting and non inverting inputs are mentioned the other way, should be non inverting to the capacitor and the resistor and the inverting to the voltage divider
I am a visual learner, and this video FINALLY made the concept and operation of an Op Amp understandable. I can't believe I graduated with honors without learning the logic/operation of an Op Amp lol.
This video helped in my understanding, thank you!
This is so informational i love it!
Great overview Karen!! One of the more versatile and useful devices in your circuit arsenal. There are some great OP AMP cookbooks out there from classic authors like Forrest Mims III.
That is the quintessential bible for opamp circuits.
Superb explanation about opamp usage.
What a straightforward explanation!
Thank you for actually explaining the _mechanisms_ as well as elaborating a bit on the basic terms :)
Most videos just show some footage and throw formulas in your face, it feels like those are made for people who already know the material.
Thanks for the video! Its really helped me for my studies.
Omg I’ve just found this channel and I’ve never properly understood these dam things! Thank you!
Watching from São Paulo , Brazil. Thanks Karen! :D
Very good explanation of the op-amps. Easy to understand, clear and concise. Thanks much.
good vid! As you noted-They are very sensitive…and amp projects taught me that discreet component values are almost never exactly as rated…lol. I really didn’t understand them until i set up a dual rail power supply…and then it all “clicked”…to this day-i test every component for actual value…
Knowledgeable and clear explanations.
Thank you so much for this video! The explanation right at 3:17 finally got it to click in my brain why people use these as buffers, even after years of explanations that felt like they were avoiding the question.
Great to hear!
Excellent review covers a lot of use cases, I'd have liked some of the images on screen longer.
But great information for revising theory.
So Opamps are just circuits with output voltage proportional to input voltage! Great video!!
Now I found a right place. Thank you very much for your knowledge sharing .
You Tube algorithm finally came through with something useful. Didn’t even need to hear the content to sub, Element 14 is awesome
Excellent explained basics of OPAs.
Karen, I am a retired auto tech building a 1967 Chevy pickup for myself. Using the “Op Amp” for a low fuel lamp. Now, with 0 ohms = Empty and 90 ohms = Full. Using this variable input into the inverting input could be used for turning on an LED. To set the point of this “On” signal for the LED, the non-inverting side can be the sweep of an 100 ohm potentiometer connected to B+, the sweep connected to the non-inverting (-) and adjusted for a resistance inside the fuel tank to 2 gallons, 3 gallons or whatever a guy/gal wants for a warning reserve. Using a 470 ohm resistor to an LED fixture marked low fuel would not effect the gauge, tank sender or the circuit. I am just bringing my project into the 21 century so my wife or son could drive safely but with reliability. After 40 years, I have found that is you over build a component and add it into a service manual, will last way longer.
As a guy who would build an automatic to handle 600 HP, but only have 400 HP driving it. Properly cooled, it would last 30 years, instead of 10. On my idea of using an “Op Amp” in this fashion, would or should this work and be reliable? (LM358, 100 ohm pot, soldered terminals with shrink wrap and dielectric grease) ASE Master Tech since 1978! Thanks.
amazing video! would be interested in a part 2.
God where was this video when i was taking circuit theory 4 years ago 😭😭 excellent work ty
Wow! Thank you Karen. This is the best description of op-amps I've seen.
I love your videos, really good explanations and nice animations thanks!
Great vid. Maybe the best opamp vid i have come accross thankyou
Great video. Just hit me that *preserving* and amplifying the input signal is the key piece here. Rather than just boosting the voltage and not preserving the signal. Obvious maybe but that helped a ton
Wonderful video highlighting the power of TH-cam
I believe this video give us an excellent introduction to OpAmps; Well done! clear and concise overview of op-amps
Wow.... what a blast from my electronics technician days past!! I was an electronics tech in the 80s. Sometimes I really miss the days of troubleshooting circuits with a DMM and/or a scope. Fun times!!
Hi Karen can you make a series of each opamp "use case" ? i never found an exhaustive list that explains in depth each case. Thx
^^ I second this
Rt
Well if you wanna go deep, there is a book(more like a short pdf) "op amps everyone" by texas instruments which explains about some applications of op amp as Audio,Video,Instrumentaion amplifiers
@@saimanojnelavelli5911 thanks
She is a karen
Hi, i like this kind of corses in electronics and the way you teach it. Thanks.
Wow, clean pictures, again! This is good stuff to know and apply.
I'm going to have to go over your previous videos to break it down for the old guy. It almost makes sense. Be right back!
Thanks! I've been making my own graphics for a while now. I hope they help make the information easier to understand.
Amazing explanations, keep on.
Thanks, Karen. This was productive.
many thanks ! to you and op Amps inventor
Thank you sssooooo much!!
As a woman engineer, I felt sooo empowered to see you explaining. Keep the good work going 👏
Awesome description!
beautiful explanation
professional is always professional.verynice job.thanks
Excellent video 😊 Congratulations!!!
Awesome explanation!
Most useful information about op amps thank u so much
Thanks very much indeed. I would like to know about the role of Op-amps in fast transient Low Dropout Regulator Circuit.
All problems clear.
Thanks for make this video
I really appreciated your descriptions and verbage.
Your an impressive teacher....
Thank you. A lot of work goes into the wording used in my videos.
Excellent explanation
Much appreciate clearing my doubts
I think there is a small error at 6:22 where you short the 2 op-amp terminals together. Also, it should be negative feedback for operation stability; therefore, the formula signs change.
Your concept is clear and instructional. It is helpful. Thanks.
At 6:22 Swap the + and - OpAmp inputs to the resistor network. Remove the wire connecting R₁ to R₂.
Also: R₁ = R₂ and R₃ = R₄.
Now the equation applies.
excellent lecture...far better then my university class .....
I would love to see some circuit analysis videos 😁
Great video, simple, efficient, easy to follow. Thanks
Great the best explanation yet, thank you a lot
Thanks for the video, that helps me undferstand the bits I wasn't sure about. One question, what are all those posters in the background? They look like they could be helpful for identifying components and the like. If they are, where can we buy them?
I got a lot of them from TinkrPostr. You should be able to buy them there.
For the differentiator you are swapping the feedback capacitor with the input resistor (not the resistor at the input with feedback resistor as narrated). The image shown is correct though. Awesome video thank you.
Excellent Class Thank you
Hi there, nice video ! can you explain how op amps (lm393) are used as over voltage protection in ATX power supplies. Thanks.
Thanks for breaking this down Karen.
When I was in the Navy I worked on a machine that had hundreds of individual circuits, each tuned to create a different analog symbol on a display screen. All of them used an op amp to shape the circuit to make things like plane, subs, boats, numbers, everything you can imagine. But instead of drawing them digitally like nowadays, the Navy used thousands of op amps instead.
that was so much informative thank you
Nicely done!
Well a couple comments:
First: I appreciate your efforts and in general think you did a very good job.
Second: As the audience I am a retired theoretical mathematician that is venturing into op-amps because I want to construct an instrument-pickup pre-amp similar to a Mic pre~amp for the acoustic stringed instruments I've built in my retirement, thus I am without what many who pursue electronics have derived as being the case or required without needing to be indicated.
Therefore, I suggest, please make it clear in the presentation the two following conclusions and one extra conceot I have derived thru experimentation and have indicated in 1 thru 3 seen below.
1: When you say Voltage at the (+) input is greater than the Voltage at the (-) input I think it should be indicated that Sign indicating polarity matters for the order relation of greater, equal to, or less than. eg, (-6 volts) is less than (+6 volts), they are not equal.
2: The (+ input), (- input) difference that is multiplied by the gain=M, idiosyncratic to the device, should probably be indicated as being the result of the absolute value of [(volt at + input) - (volt at -input)], not the difference of V-, V+ without absolute value being indicated because it can make a difference that is not intended.
&
Regardless of which input receives the signal, where this is either the (- input) or the (+ input),
for any given instance of the output Voltage when the Vdiff is below the saturation threshold we have Vout, in magnitude without sign, equals M times the absolute value of Vdiff. & (if Vdiff equals or is above the saturation limit Vout is either equal to the Voltage at one of the rails in a Dual Supply scheme, or at O volts or Vcc in a Single supply scheme)
&
This Vout has a Sign or polarity of (-) if and only if the Voltage at the (- input) is greater than the Voltage at the (+ input),
&
This Vout has a Sign or polarity of (+) if and only if the Voltage at the (+ input) is greater than Voltage at the (- input),
&
The Sign or polarity is in part dependent on what establishes ground where this can be in the case of a Single supply system what is commonly thought of as where the (-) terminal of the supply attaches and often though of as O volts.
or
It can be the floating or virtual ground established in a Dual Power supply where it has a value of Zero much like Zero found on the subset or partition of the Real number line called the interval of [-5 to +5].
3: I also think the Dual Supply scheme should be explained where it can be easily thought of as two batteries in series where the (+) end of one battery provides V+, & the (-) end of the other battery provides V-, & the ground or floating ground or what ever the reference point is called that consists of where the two batteries actually connect to each other in the Dual scheme is the ground being referred to. (I see this as important because many diagrams for simple non-inverting amplification of the signal are actually meant for the Dual Supply scheme & likely will otherwise match every part of the signal input to Zero volts at Vout if a Single power supply is used with the (-) terminal of the battery acting as ground & with a resistor to ground in a voltage divider connected on its plus side to the (- input) pin as I found out by not realizing the Dual scheme was required and it was a bit of a bitch to figure out why it was not working as advertised.
Aside from what I suggested being added, you gals and guys did good and I think my adds would just inch it to, did a really great or fabulous job.
Thanks again for the video....
Hi, thanks for this video it's really good, one think on differential amplifier at 6:20 in the video, the positive and negative inputs look shorted and they should not be. thanks.
You are right, the should not be shorted and they look like they are. Good catch
Yup, I just came to the comments to make sure that someone caught that already. Well played.
Very well presented.
Nice video, now I have an idea of the uses for buffer amp ops :) ty
Good concept mam, thanks for teaching
38 years ago, when Multiplying Digital to Analog Converters (MDACs) were invented, techs like me and the engineers we worked for had great fun coming up with all kinds of ideas for Filters and Amplifier stages with tremendous signal-to-noise, dynamic range, and frequency profiles that became possible using OpAmps like the LM318 and MDACs. For instance, put and MDAC into that Feedback loop described. Think the OpAmp has high gain to begin with? Adding an MDAC there adds Digital Control and even more Gain.