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.
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)
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.
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.
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.
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!
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.
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!
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 .
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.
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.
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.
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.
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!!
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.
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)
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.
@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
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.
This is a fair explanation for someone who already understands op amps. I wish it was directed more toward beginners. Example: You show AC sine wave voltage to the + pin and a square wave at the output. It would have been so easy to show an actual (or animated) oscilloscope trace showing the input crossing 0 volts and the output changing polarity. Single power supply only makes it more difficult to understand. The unity gain buffer is also difficult to understand as you don't explain that the output is essentially trying to drive the -pin to equal the +pin. I couldn't get any further.
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 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.
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.
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.
Karen, I think one of the more interesting op-amp circuits is simulating a large inductance with a gyrator configuration. Actual large inductors are heavy and bulky but a two port op-amp gyrator is only a few small components, making the circuit very compact. It's a convenient way to produce an inductance in the Henrys.
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…
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....
Yup! It went to the next slide and then I go wait that didn't look right, lol -- the connection between the non inverting and inverting inputs just need to be erased -- so R1 still connects to R3 and R2 still connects to R4, but the connection between those two nodes just needs erased :-) So you could just save that picture and erase that little line and be good to go with a nice basic diagram for a differential amplifier :-)
In the mid-1970s, I worked as a quality control inspector for a firm that made these.... but even though I was an electronics school grad, no one there ever satisfactorily explained what they were for, and how they did it. . . . . .
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!
The best thing about OpAmps is they neither affect the previous circuit (high impedance) or the next circuit (low impedance). And you can control the output impedance by putting a series resistor, do whenever the output load is 0 ohms your impedance in the output will always be what you defined in the series resistor.
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!!
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.
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
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.
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.
When I learned about op-amps, back in the early 90’s, we learned all about their originals use in early computers. Operational Amplifiers, are called that because they were originally used for Math (Operations). That small voltage triggered the high voltage low or high to trip relays, denoting a binary state. Later on an op-amp, like the 741 that we used in solid state circuits much later on, was not really about using it for high gain applications but rather as part of rudimentary logic circuits while other op-amps were designed specifically amplification. In summary’s, Summing, mixing and opposite phases are all the things you need to do binary logic and op-amps were originally designed to do just that. It has been a while since I have thought of this stuff, almost 3 decades, but that is my recollection. Cheers all.
At 6:20, that "differential" amplifier is not even close. First, the opamp's inputs are shorted together so you will see only its drift/common mode at the output. Second, the inverting and non-inverting inputs are backwards; the feedback must excite the inverting input for negative feedback. Third, the output equation is wrong. If you flip the opamp, remove the shorting segment, and make R4=R3 and R2=R1, then the output will be Vout=R3/R1(V2-V1) within the opamp's specifications and power supplies. At 7:10, integrators are LOW pass filters and the circuit you show is an integrator; the capacitor integrates the charge flowing through R3. The sin(.) at the input should become - Acos(.) at the output. At 7:20 and 7:40, your opamps need flipped once again, but that one-shot won't work anyway -- your trigger MUST zero the capacitor's charge first.
Pause at 6:22. Is there a typo in this circuit? The 2 input signals are shorted. There is no way the amplifier is able to amplify if both inputs are always going to be equal because they are shorted together.
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.
This is a great video, but just like dozens of others there is no real world applications that they are referenced to otherwise it's the same old description. The first one who does a video that shows the multiple applications of op-amps how they're used in the circuit what in the circuit is used to control it and what hardware outside the circuit is ithe nput and output from the op amp wins the prize. All op amp videos I have seen begin beyond the beginner stage and many are lost in what their real world applications are. 8:45
Question here: @3:45 you mentioned that an op amp can turn a sinusoidal ac wave to a square DC wave.. would the square wave not also be alternating between a positive and negative voltage making it not DC and still AC. Genuinely confussled, any responses help.
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
Op amps are used in control systems and they can be used as controllers. For example, PID can be implemented by adding a capacitor parallel to a resistor connected to inverting input and a capacitor in series with a resistor as negative feedback and non inverting input is grounded. If you analyze it in S domain by using laplace transform, you get the PID expression, but the output will be inverted if you try to implement the specific circuit
@@duality4y with openloop it doesnt have the dampening effect on the output so the voltage will always shoot the minimal and maximum supply voltage (for example +9V and -9V)
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.
when using OPAMPs to control a solenoid to a control valve, FEEDBACK MINIMIZES HUNTING when a change is needed. It is somewhat hard to explain without a drawing, but basically Hunting is when the valve opens/closes too much then having to close/open back to compensate and once again overshooting, so on and so forth until it finally stablizes out. Feedback makes for much smoother and finer control
A) The amplification op an Opamp can be extreme, yes, but the comparator circuit does not act as a schmitt trigger (vid on 2.54 etc, so not "full throttle" to the supply voltage) B) the differentiator circuit on 6.25 cannot work because there is no voltage difference between the (-) and the (+) input, they are shortcut. Apart from that: an interesting video!
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.
@@pesekmar in my opinion a DC signal is non transient. Means: There is no variation in time by the level of voltage. "Alternating Current" means the signal is alternating between e.g. +A and -A. When you add an offset of +B, where B = A, the squared signal alternates between B+A or 2A and 0. Otherwise: Compare with fourier series and subtract the part, where the frequency is zero aka offset or DC part.
@@pesekmar 3:42 oscillates between saturating negative (-Vs) to saturating positive(+Vs). it need not be ground. in this example shown, definitely not dc.
@@Ham549 I have to agree with kturst s, The potential goes to negative as wel as positive. And since AC stands for alternating current, and the in this scenario the direction of the current is alternating as well so I would call it AC, not DC. Pulsed DC will never turn into the negatives numbers, otherwise it wouldnt be called Direct Current.
I learned "virtual ground" is a big aspect to op-amps. I never fully grasped the concept to my satisfaction, but the way I understand it is the current between the two inputs is so small a virtual ground potential is present between them. That is if one of the inputs, either the inverting or non-inverting, is pinned to ground. Can anyone offer more on this? It's a great video, and I would have loved to have it as a learning resource back in the day.
You understood it wrong. There is no such thing as a 'virtual ground potential'. In an inverting configuration, the non-inverting input is grounded and the inverting input presents a virtual ground because the opamp works to keep the voltages at both inputs the same. In this mode the opamp is sensing input current rather than voltage, as the voltage is always zero. That's why it is a virtual ground.
Nice overview Karen, thanks! One note, I THINK you reversed the resistor-capacitor and voltage divider attachment points (inverting vs. non-inverting) when you described the astable multivibrator circuit at ~7:25.
At 7:25, swap the OpAmp inputs in the diagram to get the astable multivibrator. The circuit needs positive feedback to slew rapidly and negative feedback to delay the flip to the opposite polarity.
Your thumbnail shows V1 > V2 with the output at the negative rail Way to go to confuse folks. And you have the inputs reversed again at 7:25 on the astable multivibrator.
Interested in OpAmps? Check out this fresh content from Derek's on the topic here: ua-cam.com/video/kF1wGW-h4Y8/v-deo.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.
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!
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
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.
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.
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.
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.
@@openyoureyes7539 exactly same here. Just when you start thinking you understand smth, the teacher makes a mistake like that..
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 .
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 🤣👍
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.
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.
Hands down, this is the best op-amp tutorial
Probably the best explanation of op-amps I've seen so far. Thanks!
not quite
The best explanation of the basics of Op Amps I have ever seen...
Perfectly explained refresher of op-amps. Just what I needed. Thank you!
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.
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!!
Really great, simple, clear, precise, going straight to the point. Thank you for this perfect video as we would like to see more often.
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.
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
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.
Brilliant Explanation. The whole OpAmp summed up in the best possible way !
Thank you for taking the time to explain op amps.
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
You Tube algorithm finally came through with something useful. Didn’t even need to hear the content to sub, Element 14 is awesome
Thank you sssooooo much!!
As a woman engineer, I felt sooo empowered to see you explaining. Keep the good work going 👏
This is a fair explanation for someone who already understands op amps. I wish it was directed more toward beginners. Example: You show AC sine wave voltage to the + pin and a square wave at the output. It would have been so easy to show an actual (or animated) oscilloscope trace showing the input crossing 0 volts and the output changing polarity. Single power supply only makes it more difficult to understand. The unity gain buffer is also difficult to understand as you don't explain that the output is essentially trying to drive the -pin to equal the +pin. I couldn't get any further.
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 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.
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.
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.
Perfectly explained of op-amps. Just what I needed. Thank you for Perfectly explained
Karen, I think one of the more interesting op-amp circuits is simulating a large inductance with a gyrator configuration. Actual large inductors are heavy and bulky but a two port op-amp gyrator is only a few small components, making the circuit very compact. It's a convenient way to produce an inductance in the Henrys.
Great video, it made so much EE come rushing back into my brain.
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…
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....
Your differential amplifier circuit has an error in it....there should be no connection at the R3/R1 to non inverting pin...
thank god, i am a beginner, so, i was totally wrecking my brain over how it could possible work...
Yup! It went to the next slide and then I go wait that didn't look right, lol -- the connection between the non inverting and inverting inputs just need to be erased -- so R1 still connects to R3 and R2 still connects to R4, but the connection between those two nodes just needs erased :-)
So you could just save that picture and erase that little line and be good to go with a nice basic diagram for a differential amplifier :-)
Great lecture Karen . But I guess I will have to attend this lecture a few times more . Subscribed 😀
In the mid-1970s, I worked as a quality control inspector for a firm that made these.... but even though I was an electronics school grad, no one there ever satisfactorily explained what they were for, and how they did it. . . . . .
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.
God where was this video when i was taking circuit theory 4 years ago 😭😭 excellent work ty
The best thing about OpAmps is they neither affect the previous circuit (high impedance) or the next circuit (low impedance). And you can control the output impedance by putting a series resistor, do whenever the output load is 0 ohms your impedance in the output will always be what you defined in the series resistor.
did not know that , nice to hear that , that piece of info is worth of gold
So Opamps are just circuits with output voltage proportional to input voltage! Great video!!
This is the best video I've ever seen for op-amps srsly
one can not be greatful enough that someone like you explains things so that they are very easy to understand.
A very good video.
So far the best basic Op-Amps explanation in youtube.
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!!
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.
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
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.
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.
Omg I’ve just found this channel and I’ve never properly understood these dam things! Thank you!
When I learned about op-amps, back in the early 90’s, we learned all about their originals use in early computers. Operational Amplifiers, are called that because they were originally used for Math (Operations). That small voltage triggered the high voltage low or high to trip relays, denoting a binary state. Later on an op-amp, like the 741 that we used in solid state circuits much later on, was not really about using it for high gain applications but rather as part of rudimentary logic circuits while other op-amps were designed specifically amplification. In summary’s, Summing, mixing and opposite phases are all the things you need to do binary logic and op-amps were originally designed to do just that. It has been a while since I have thought of this stuff, almost 3 decades, but that is my recollection. Cheers all.
I was taught this: AnOp Amp will do anything to make it two inputs equal, regardless how it is setup.
Great scott🙂
Only if there is NFB.
At 6:20, that "differential" amplifier is not even close. First, the opamp's inputs are shorted together so you will see only its drift/common mode at the output. Second, the inverting and non-inverting inputs are backwards; the feedback must excite the inverting input for negative feedback. Third, the output equation is wrong. If you flip the opamp, remove the shorting segment, and make R4=R3 and R2=R1, then the output will be Vout=R3/R1(V2-V1) within the opamp's specifications and power supplies.
At 7:10, integrators are LOW pass filters and the circuit you show is an integrator; the capacitor integrates the charge flowing through R3. The sin(.) at the input should become - Acos(.) at the output. At 7:20 and 7:40, your opamps need flipped once again, but that one-shot won't work anyway -- your trigger MUST zero the capacitor's charge first.
Pause at 6:22. Is there a typo in this circuit? The 2 input signals are shorted. There is no way the amplifier is able to amplify if both inputs are always going to be equal because they are shorted together.
Great intro video on op-amps! One of the best I've seen. Thanks!
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!
Wow! Thank you Karen. This is the best description of op-amps I've seen.
Wonderful video highlighting the power of UA-cam
This is a great video, but just like dozens of others there is no real world applications that they are referenced to otherwise it's the same old description. The first one who does a video that shows the multiple applications of op-amps how they're used in the circuit what in the circuit is used to control it and what hardware outside the circuit is ithe nput and output from the op amp wins the prize. All op amp videos I have seen begin beyond the beginner stage and many are lost in what their real world applications are. 8:45
Question here: @3:45 you mentioned that an op amp can turn a sinusoidal ac wave to a square DC wave.. would the square wave not also be alternating between a positive and negative voltage making it not DC and still AC. Genuinely confussled, any responses help.
Watching from São Paulo , Brazil. Thanks Karen! :D
Great content, sometimes we just need to know the different ways things manifest before actually knowing how they do it like some other videos do
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
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.
Op amps are used in control systems and they can be used as controllers. For example, PID can be implemented by adding a capacitor parallel to a resistor connected to inverting input and a capacitor in series with a resistor as negative feedback and non inverting input is grounded. If you analyze it in S domain by using laplace transform, you get the PID expression, but the output will be inverted if you try to implement the specific circuit
excellent lecture...far better then my university class .....
Very nice explanation. You basically covered a full undergrad course on Elemental Electronics in less than 9 minutes. Cheers!
You must have studied at a very bad university then.
The op-amp rule of thumb:
"Op-amp will do all it can, to make both inputs equal (same voltage)"
And openloop?
@@duality4y Then it's a comparator! :)
@@duality4y with openloop it doesnt have the dampening effect on the output so the voltage will always shoot the minimal and maximum supply voltage (for example +9V and -9V)
Only if there is NFB.
Great video, simple, efficient, easy to follow. Thanks
Great video, many thanks. And now a How OpAmps Work part 2 followup, please.
Great video! I own a Boulder 500AE NOS amp and this was a terrific tutorial. It is an op amp.
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.
You explain better than my professors.
These are such awesome videos, I love how they explain how just about every concept works in a very practical and useful way.
when using OPAMPs to control a solenoid to a control valve, FEEDBACK MINIMIZES HUNTING when a change is needed. It is somewhat hard to explain without a drawing, but basically Hunting is when the valve opens/closes too much then having to close/open back to compensate and once again overshooting, so on and so forth until it finally stablizes out. Feedback makes for much smoother and finer control
What you describe is really integration. NFB causes the hunting: integration damps it.
Thanks, Karen. This was productive.
“You cannot magically turn 1volt into 100 volts”
Me: *slowly glances toward my boost converter*
And since the 1V is not explicitly stated as being DC, a little thing called a transformer might also perform the magic …
A) The amplification op an Opamp can be extreme, yes, but the comparator circuit does not act as a schmitt trigger (vid on 2.54 etc, so not "full throttle" to the supply voltage) B) the differentiator circuit on 6.25 cannot work because there is no voltage difference between the (-) and the (+) input, they are shortcut. Apart from that: an interesting video!
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.
Thanks for the video! Its really helped me for my studies.
Very good explanation of the op-amps. Easy to understand, clear and concise. Thanks much.
tomorrow is my exam and boom I'm here today! but video was great i understand everything....
Now I found a right place. Thank you very much for your knowledge sharing .
Pardon me, your differential amplifier has the inputs shorted so it could not amplify any input differential voltage.
Great vid. Maybe the best opamp vid i have come accross thankyou
Why do you call conversion of 'sinusoid to square' as 'ac to dc conversion'...?? That's wrong.
The supply of the opamp is connected to gnd so output never goes below 0 (minus V) ... so it is DC.
@@pesekmar in my opinion a DC signal is non transient. Means: There is no variation in time by the level of voltage. "Alternating Current" means the signal is alternating between e.g. +A and -A. When you add an offset of +B, where B = A, the squared signal alternates between B+A or 2A and 0.
Otherwise: Compare with fourier series and subtract the part, where the frequency is zero aka offset or DC part.
@@pesekmar 3:42 oscillates between saturating negative (-Vs) to saturating positive(+Vs). it need not be ground. in this example shown, definitely not dc.
@@santhoshwagle9857 pulsed DC
@@Ham549 I have to agree with kturst s, The potential goes to negative as wel as positive. And since AC stands for alternating current, and the in this scenario the direction of the current is alternating as well so I would call it AC, not DC. Pulsed DC will never turn into the negatives numbers, otherwise it wouldnt be called Direct Current.
I learned "virtual ground" is a big aspect to op-amps. I never fully grasped the concept to my satisfaction, but the way I understand it is the current between the two inputs is so small a virtual ground potential is present between them. That is if one of the inputs, either the inverting or non-inverting, is pinned to ground. Can anyone offer more on this?
It's a great video, and I would have loved to have it as a learning resource back in the day.
You understood it wrong. There is no such thing as a 'virtual ground potential'. In an inverting configuration, the non-inverting input is grounded and the inverting input presents a virtual ground because the opamp works to keep the voltages at both inputs the same. In this mode the opamp is sensing input current rather than voltage, as the voltage is always zero. That's why it is a virtual ground.
Nice overview Karen, thanks! One note, I THINK you reversed the resistor-capacitor and voltage divider attachment points (inverting vs. non-inverting) when you described the astable multivibrator circuit at ~7:25.
Dino Papas who.. what?
At 7:25, swap the OpAmp inputs in the diagram to get the astable multivibrator. The circuit needs positive feedback to slew rapidly and negative feedback to delay the flip to the opposite polarity.
speaking of positive feedback , great video thanks ....
Well done! clear and concise overview of op-amps.
What a straightforward explanation!
You should mention current mirrors as the basic principle of operation.
AM I THE ONLY ONE WHO SEEN THE POINTER FINGER IN THE BACKGROUND? IT WAS SO COOL
You want to know how OP amps work? They go to 11! That's what makes them so OP.
Your thumbnail shows V1 > V2 with the output at the negative rail Way to go to confuse folks.
And you have the inputs reversed again at 7:25 on the astable multivibrator.