How Op Amps Work - The Learning Circuit

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[professorcouto]

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!

[Wazza-kj]

Hi Karen
For years I have listened to people 'blabber on' about how they are tying to teach me electronics and occasionally throwing me 'tidbits'' of useful information.
I have leaned more from you (Karen) than all of those who profess to be 'professors'.
Your teaching abilities are of the highest standards. Never stop.
Best wishes
Warren.

[redcheekgirl]

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!

[ltjgambrose]

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.

[Wavicle]

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.

[amratsingh]

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.

[josefonseca]

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!

[sujoypaul]

she explained the subject in mins what my professor couldnt in 40 hrs of university classes

[MrLee-cypw]

I came for a refresher but was absolutely amazed at how well and clearly you broke this down. Excellent video!

[OPAAM]

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!

[DavidHughesss]

This was extremely useful. No fluff, straight to the point, helped me understand a couple of relatively basic things that I was confused about. Thank you!

[jordondigdon]

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.

[Sven-der-Technik-Freak]

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.

[TheYooToob]

Good video. Had to watch for a class. I have never understood something less in my life.

[obelusyt]

Hands down, this is the best op-amp tutorial

[klong]

Very fast, short, brief introduction to OpAmp .For three years since 2017, I never 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 .

[axontech]

The best explanation of the basics of Op Amps I have ever seen...

[michaelh]

Thank you, you're the first video i've watched that actually showed me what is inside an op amp

[antonialopez]

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.

[mab]

Your content and method of presenting it are very interesting. Keep it up. I have found a minor mistake in the differential circuit in the video at 6:13: Both inputs are short circuits.