The class B output is because the classic 2-diode-drop compensation circuit used to make class AB is missing. Even the lowly and ancient '741 and nearly every other bipolar op amp since, is class AB. Adding a pull-down or pull-up resistor converts class B to Class A. Better distortion and faster, but draws a bunch more power. Not good for low power apps. I have designed with opamps since 1970, used many LM358s as my go-to jellybean, and just learned about this a few years ago. Thanks, and keep up the great videos!
The modern rail-to-rail CMOS op amps are so much better and not THAT much more expensive! I have boxes of older op amps I NEVER use (LM308, uA709 ! uA725, uA741) because they have such involved compensation or poor performance. Even free they are not good choices compared to modern amps that can be had for a dollar or two.
The only shortcoming of the rail-to-rail CMOS op amps is that they usually have a much lower max supply voltage. So for higher voltage applications they often can't be used. For 5v or 3.3v single ended applications the CMOS op amps are definitely the way to go.
If frequency compensation of an op amp causes you grief, don't every try to design a switchmode power supply where you have to figure out where all the poles and zeros need to be.
@@argcargv I made a number of designs with uA709, a couple even after I had switched otherwise to '741. Why? Because I needed the uncompensated extra speed. The '725 I needed in my 10-amp analog simulator bench for lower offset and especially better thermal & longer term drift. Later on, of course I have had other options, like OP-27 and OP-37. If you need an easy output voltage clamp, the LM308 would be hard to beat. The only one I actually remember having had losing battles has been LM318. Using it is difficult on PCB, and impossible on the solderless proto board. If somebody has had better experiences - here comes my congratulation!
I've used the LM358 quite a bit, but I only use it single supply applications like buffering ADCs and other primarily digital applications. It really seems optimized for that sort of thing. You know, the short bus. LOL!
Wow I had not seen that app note before. It is a real gem. I think it would be useful to know some of the details even if you aren't using a lm358 just to have a better understanding of some of the design constraints of op amps.
TI used to have a document titled "IC Op Amps for Everyone" or something like that. It is a good introduction that covers lots of the issues that can arise. I don't know if it is still available.
One other source I should have mentioned is the multitude of analog ap notes written by the late Jim Williams. You can find stuff by him, identifiable by the oscilloscope images, in National Semi ap notes going way back. He joined Linear Tech and started cranking out lots more. For years I'd tell people I thought he wrote the best ap notes in the industry. They weren't just "here's how to use this part" but short courses in all sorts of important matters. Eventually he started getting the notice he deserved. There is also lots of good stuff from Analog Devices. Don't dismiss old applications information because it is old. It is quite true that the specific parts used may be inferior to new parts, but the core information is still very valuable.
I wonder if you could grind or mill the package to reveal the die and see if there are markings which identify the chip? Anyway nice work with the identification.
If they're plastic packages, you can heat them and grab with 2 pairs of pliers, and kindof twist the package - the die will become exposed and separate from the package. Curious Marc has a video about that. Is really quick, and not messy compared to every other method. The only other method needed is chemical etching, if keeping the bond wires intact is important (aka you want to do electrical testing and don't have a probe station)
This is very interesting and something I also was not aware of. I think this explains some bad circuit behaviors I have seen in the past. Thanks for bringing this to our attention.
3140/3240 were awesome. I’ve used them when I was a kid and they were noisy but otherwise easy to use. For use close to DC, the feedback networks could be silly like 1M/1M to get gain of +2. Today the TLC parts do this well and are cheap and less noisy.
LM358 input stage can "see" below its negative rail, therefore it's extremely useful in some control (e.g. power supply) applications where the crossover distortion has no effect. You can build a true zero-volt (or negative few hundred millivolt) comparator with an LM358 while being positive single-supplied. Crossover distortion is mostly an analog signal processing problem.
I have had a lot of fun making these devices work. The Linn Valhalla turntable power supply has 0.05% THD 50 Hz using them. The circuit is very remarkable and was low cost. 90 Vrms using TV type T0220 outputs. The output class A 1 watt. I have a hunch better using this device. CD4060 with cascaded 324 to get a very pure sine wave. There are a few easily corrected weaknesses in the design. Nothing to do with the 324. LM339 looks like a similar starting point. In low speed switching 324 makes a versatile comparator that unlike 339 can source current. 339 circuits generally work including hysteresis. LM386 looks generic. The pull up pull down resistor class A trick can be a transistor current source or sink. A resistor almost as good. I think I read into a high impedance crossover distortion vanishes. Hiss alas is high. I read the designer was disappointed with it's performance. 741 was supposed to be it's rival. Selling it cheaply Tesco it. It survived whilst LM833 didn't as best I know. LM833 is sometimes better than NE5532. Ironically 833 were the same price as 358 recently. MC33078 similar. There was a cheaper 324 often referred to on data sheets. These I believe were fall out voltage specs. This suggests all were tested!
Good to know. I had issues with using them also. I will have to review the App notes. I recall the crossover distortion mentioned in my ancient National Semiconductor data books from 1983. I will have to review them and see if my issues were due to these quirks. THANX I love Chippahdahday series.
I love the LM358. 😁 I often use it for sensor amplification and active filtering because it doesn't require a negative rail and works very well with both 5V and 3.3V MCUs, and it's cheap and DIP-8.
I love them also, and the LM324. I like them for hobby and actually i am still using them in new commercial designs if they are for single supply and low cost. On the other hand i almost do not use the TL 06x TL07x TL08x any more because i had lots of trouble with the phase reversal. Okay i have some of them on stock for repair or when building existing designs - but everything new (for hobby and for commercial as well) i avoid them. For new designs one of my "universal" go to opamp is the TLC2272...
HP engineers knew what they were doing. They knew where an amp like that was suitable and where it wasn't. I'm sure many of them would have swooned with glee if presented with some of the op amps that are around today. Or, like me, they might have cursed because everything looked perfect til they got to the line bringing the huge disappointment of low supply voltages.
The LM324 is still a current and popular chip from ONSemi in SOIC form and has many advantages over most other dual rail op-amps. it's still commonly used in single supply equipment and will work on a 3V supply rail. With op-amps, it's horses for courses. When you dig down there are often many subtleties that differentiate one from another and just treating them all as if they're interchangeable isn't necessarily a wise stance.
Yes, indeed. The 324 is a perfectly serviceable amp for lots and lots of applications but it does require you know what you are doing to apply it properly. I've used them in a lot of industrial electronics designs and they've performed quite satisfactorily with excellent reliability. I didn't use them because they were cheap but because they were suited to the job. I've designed other stuff for which they wouldn't come within a hundred kilometres of what was required. I chuckle when I hear people say what a great voltage reference the TL431 is. It's another part that is perfectly good for lots of things but it is a pretty low-end voltage reference. If I were still doing design I'd still be finding places where I'd use it, just as I would find places for the LM324. I've been wandering around watching electronics videos on TH-cam. I'm not doing it to learn things, but to evaluate the quality of the information being put out by people purporting to teach electronics to others. The content ranges from very good to absolute rubbish, with lots of mediocre stuff with mistakes and poorly founded opinion. This channel seems to be a better grade of mediocre.
So if you're using two of them, you'd tie one output to +Vcc and the other one to -Vcc to balance the load on the power supply rails? Or would that not matter?
I love the 258, 258A (358) since it has ground sensing capability and single rail I use it for many things, Did you know that you can use the 358 as audio amp with a single rail configuration without crossover distorsion? I designed a small amp using single rail and it sounds great if you bias the chip correctly, however the weaker side of the 358 is that is has quite a bit of white noise when nothing is playing and I am trying to find a way to make this less if possible
Some of the noise will come from the amp itself and there's nothing you can do about that (other than use a lower noise opamp), but some might be Johnson noise from the resistors. Try redesigning the circuit to use lower value resistors and use decent quality metal film parts. But make sure the amp can supply the higher currents involved. It may be enough to eliminate some of the noise you're hearing.
@@RexxSchneider thanks for the input. I think most is coming from the amp itself in this case but as you say components can play a big role in sensitive circuits too. I will have this in mind when I keep work on this project next time :)
At least the TL072 has the same pinout as the LM358. I have a bunch of 8-pin opamps suspected to be LM358s but were relabeled by the Ebay seller as 741s. Wiring up a LM358 to 12V as if it were a 741 did not end well
My understanding is that its output stage is a Class B push-pull amplifier with the known crossover distortion which is fixed by placing two diodes in series between the npn base and the pnp base. Those diodes are missing in the LM358.
@@andymouse It depends on what you think "properly" means. If you directly drive both bases of complementary output transistors, then you will find a "dead band" where neither transistor is on. That is not quite Class B operation. If you add a couple of diodes between the bases and push current through the diodes, you might just find the point where both output transistors are just starting to conduct, which would be the ideal class B operation. Unfortunately, temperature changes and mismatches make that unrealistic, so we generally try to turn on both output transistors a little bit. That tends to eliminate the cross-over distortion caused by the "dead band", at the cost of significantly increasing the quiescent current consumption of the amplifier. The LM358 has that dead band but has low quiescent current. It only takes one resistor drawing a few milliamps to ensure that at least one output transistor is turned on in applications where the dead band is unacceptable. The ability to choose between current consumption and linearity makes the LM358 more versatile, so I personally don't think there is anything improper about the internal biasing.
This is e-x-c-e-llent content! Bravo! I would really like it, if you would explore cures for the known glitches on the XR2206 and AD8038 OEM Function Generator chips. Yes, they are ancient and not in production, but that is not the point. The cure is. Thanks.
I've designed the LM324 into all sorts of industrial electronics and they have performed well and reliably. The A version is worth the extra small cost sometimes. I've designed test and measurement circuits in which the LM324 might find a place but is way, way, way out of the running in other parts of the instrument. It is all about selecting devices that are suitable for the application at hand.
@@d614gakadoug9 I have used them religiously in solar aplicaciones, and they have shows a huge resistance to static build up and esd, very rugged compared to more modern esd sensetive op amps and due to there low BW, they are generally very stable, not prone to turning into unwanted oscillators.
Is that right one can delay more and more its switching to another darlingtons group with bias resistance growth (like pnp being pushed away of common emitter rail). So it behaves like simistor with ground to rail bias controlling opening angle(delay). How much correct this thought can be? Like the videos
AFAIK, LM324 was one of earliest (the earliest?) quad op amp that could operate from a single supply. Does anyone know of an earlier one, that was as cheap and available. One chip instead of 4, and a single supply, was revolutionary.
Can you put goes across to the negative rail or the positive rail it is acting like a Class A amplifier rather than a Class B when download goes to ground
Thanks for the video. 11:00 Actually most of the opamps do from Vee+2 to Vcc-2, while LM358 goes from Vee to Vcc-2. It's better in this respect, never worse. I'm not aware of opamp that "pull up well". Also could you please clarify your statement about single-supply and dual-supply op amps in the beginning of the video? From what I know an opamp doesn't care if you power it from +/- 6V or 0 and +12V. It's all the same from its perspective. You just need to bias input signals accordingly. This being said I used only widespread/cheap op amps in my projects like LM741 / TL081, NE5532, LM358, etc. So maybe I don't know something.
Any op amp can be used with a single supply or dual supplies. The limitation in terms of practicality is how close the output can swing to the supply rails and the input common voltage range. Amps designed for dual supplies generally have an output swing of something like 2 volts above the negative supply to 2 volts below the positive supply. That makes them pretty much completely useless in lots of applications unless you use dual supplies of adequate voltage. The input common mode range can also be a significant problem with a single supply.There is more variation here, but it can be much like the output swing range - the amp will only operate properly with both inputs somewhere in that previously mentioned range. Amplifiers designed for single supply typically have a significantly different input stage that allows it to work right down to the negative supply voltage - zero volts. Of course with just a unipolar supply, inverting amplifiers can't be implemented in any case without biasing the non-inverting input at a voltage above the negative supply. If you violate the specified input common mode range odd things can happen, and this is true for any amp, even if operated on dual supplies. The worst problem in many applications is "phase reversal." You might be increasing the input signal, going positive, and the output is happily following according to the gain, then suddenly the output goes negative instead of more positive. This is really bad new when the amplifier is being used in a control loop. It's like turning the steering wheel of your car to the right and suddenly the car steers all the way to the left. Some amps, especially more modern ones, are designed to prevent phase reversal even when the inputs are well outside of the range in which proper operation is assured. You can still fry the amp with excessive positive or negative input voltage if the current is limited to just a few milliamps.
Also your original starts failing before fake one. Attenuation start dropping first on original yet fake one keeps no voltage drop which seems to show fake is a better option
Anyone who watches this video should read to app note, lest they get they get the idea that 358, 124, and 192 are weird garbage parts. All of these design choices were made to allow for low current single supply (often battery) use at a time when nearly all op-amps needed a +/- 15V supply and current could be fairly high. In addition, not being able to swing to the rails and phase reversal was a common headache with many op amps. This is a 40+ year old design by now...
It can still be a good good part if you know what you are doing. (I'm referring to a properly designed and made cheap amp from a reliable manufacturer, not the rubbish sold on ebay and the like)
@@d614gakadoug9 haha yes I was being a bit tongue-in-cheek. But at the same time how many hours of debugging ur circuit is the cost savings worth to you.. There are plenty of cases whee the trade-off makes sense
Given how cheap an LM358 is to make, and how well it works if you understand how it works and how to use it - it has its uses, and is not garbage. The engineer designing it into an application may be doing garbage job, sure, but that op-amp is still doing the same job it did the day it was first introduced. You can buy it pretty much anywhere, too. So if you’re designing a kit or something that should be of appeal to people in impoverished areas, count on 358 being available, and design for it. Even fakes are often a 358 under the hood. When you need more performance than it can provide - sure, use other parts, but someone in rural India may not be able to get on of the fancier op-amps easily. And this is just by the way of an example, it’s not like rural India is special in that respect.
The class B output is because the classic 2-diode-drop compensation circuit used to make class AB is missing. Even the lowly and ancient '741 and nearly every other bipolar op amp since, is class AB. Adding a pull-down or pull-up resistor converts class B to Class A. Better distortion and faster, but draws a bunch more power. Not good for low power apps.
I have designed with opamps since 1970, used many LM358s as my go-to jellybean, and just learned about this a few years ago.
Thanks, and keep up the great videos!
The modern rail-to-rail CMOS op amps are so much better and not THAT much more expensive! I have boxes of older op amps I NEVER use (LM308, uA709 ! uA725, uA741) because they have such involved compensation or poor performance. Even free they are not good choices compared to modern amps that can be had for a dollar or two.
The only shortcoming of the rail-to-rail CMOS op amps is that they usually have a much lower max supply voltage. So for higher voltage applications they often can't be used. For 5v or 3.3v single ended applications the CMOS op amps are definitely the way to go.
If frequency compensation of an op amp causes you grief, don't every try to design a switchmode power supply where you have to figure out where all the poles and zeros need to be.
@@d614gakadoug9 Not that much grief but more stuff to add to the circuit.
@@argcargv I made a number of designs with uA709, a couple even after I had switched otherwise to '741. Why? Because I needed the uncompensated extra speed. The '725 I needed in my 10-amp analog simulator bench for lower offset and especially better thermal & longer term drift. Later on, of course I have had other options, like OP-27 and OP-37. If you need an easy output voltage clamp, the LM308 would be hard to beat. The only one I actually remember having had losing battles has been LM318. Using it is difficult on PCB, and impossible on the solderless proto board. If somebody has had better experiences - here comes my congratulation!
I've used the LM358 quite a bit, but I only use it single supply applications like buffering ADCs and other primarily digital applications. It really seems optimized for that sort of thing. You know, the short bus. LOL!
Wow I had not seen that app note before. It is a real gem. I think it would be useful to know some of the details even if you aren't using a lm358 just to have a better understanding of some of the design constraints of op amps.
Yep !
TI used to have a document titled "IC Op Amps for Everyone" or something like that. It is a good introduction that covers lots of the issues that can arise. I don't know if it is still available.
Couldn't agree more :)
One other source I should have mentioned is the multitude of analog ap notes written by the late Jim Williams. You can find stuff by him, identifiable by the oscilloscope images, in National Semi ap notes going way back. He joined Linear Tech and started cranking out lots more. For years I'd tell people I thought he wrote the best ap notes in the industry. They weren't just "here's how to use this part" but short courses in all sorts of important matters. Eventually he started getting the notice he deserved.
There is also lots of good stuff from Analog Devices.
Don't dismiss old applications information because it is old. It is quite true that the specific parts used may be inferior to new parts, but the core information is still very valuable.
I wonder if you could grind or mill the package to reveal the die and see if there are markings which identify the chip? Anyway nice work with the identification.
If they're plastic packages, you can heat them and grab with 2 pairs of pliers, and kindof twist the package - the die will become exposed and separate from the package. Curious Marc has a video about that. Is really quick, and not messy compared to every other method. The only other method needed is chemical etching, if keeping the bond wires intact is important (aka you want to do electrical testing and don't have a probe station)
This is very interesting and something I also was not aware of. I think this explains some bad circuit behaviors I have seen in the past. Thanks for bringing this to our attention.
LM358 a staple for sure.
CA3140 and CA3240 I've always used.
Nobody likes me :)
LOL
Is anyone making the old RCA numbers anymore?
I don't even know what company owns the various remnants of RCA's semi divisions these days.
3140/3240 were awesome. I’ve used them when I was a kid and they were noisy but otherwise easy to use. For use close to DC, the feedback networks could be silly like 1M/1M to get gain of +2. Today the TLC parts do this well and are cheap and less noisy.
LM358 input stage can "see" below its negative rail, therefore it's extremely useful in some control (e.g. power supply) applications where the crossover distortion has no effect. You can build a true zero-volt (or negative few hundred millivolt) comparator with an LM358 while being positive single-supplied. Crossover distortion is mostly an analog signal processing problem.
Very informative, thanks!
I have had a lot of fun making these devices work. The Linn Valhalla turntable power supply has 0.05% THD 50 Hz using them. The circuit is very remarkable and was low cost. 90 Vrms using TV type T0220 outputs. The output class A 1 watt. I have a hunch better using this device. CD4060 with cascaded 324 to get a very pure sine wave. There are a few easily corrected weaknesses in the design. Nothing to do with the 324.
LM339 looks like a similar starting point. In low speed switching 324 makes a versatile comparator that unlike 339 can source current. 339 circuits generally work including hysteresis. LM386 looks generic.
The pull up pull down resistor class A trick can be a transistor current source or sink. A resistor almost as good. I think I read into a high impedance crossover distortion vanishes. Hiss alas is high.
I read the designer was disappointed with it's performance. 741 was supposed to be it's rival. Selling it cheaply Tesco it. It survived whilst LM833 didn't as best I know. LM833 is sometimes better than NE5532. Ironically 833 were the same price as 358 recently. MC33078 similar. There was a cheaper 324 often referred to on data sheets. These I believe were fall out voltage specs. This suggests all were tested!
Good to know. I had issues with using them also. I will have to review the App notes. I recall the crossover distortion mentioned in my ancient National Semiconductor data books from 1983. I will have to review them and see if my issues were due to these quirks. THANX I love Chippahdahday series.
I love the LM358. 😁
I often use it for sensor amplification and active filtering because it doesn't require a negative rail and works very well with both 5V and 3.3V MCUs, and it's cheap and DIP-8.
I love them also, and the LM324. I like them for hobby and actually i am still using them in new commercial designs if they are for single supply and low cost. On the other hand i almost do not use the TL 06x TL07x TL08x any more because i had lots of trouble with the phase reversal. Okay i have some of them on stock for repair or when building existing designs - but everything new (for hobby and for commercial as well) i avoid them. For new designs one of my "universal" go to opamp is the TLC2272...
yes you should not use the TL07x single rail. that is why they made the TL27x
You'd be surprised at how many of the old HP precision instruments used LM358s 🙈
HP engineers knew what they were doing. They knew where an amp like that was suitable and where it wasn't. I'm sure many of them would have swooned with glee if presented with some of the op amps that are around today. Or, like me, they might have cursed because everything looked perfect til they got to the line bringing the huge disappointment of low supply voltages.
The LM324 is still a current and popular chip from ONSemi in SOIC form and has many advantages over most other dual rail op-amps. it's still commonly used in single supply equipment and will work on a 3V supply rail. With op-amps, it's horses for courses. When you dig down there are often many subtleties that differentiate one from another and just treating them all as if they're interchangeable isn't necessarily a wise stance.
Yes, indeed.
The 324 is a perfectly serviceable amp for lots and lots of applications but it does require you know what you are doing to apply it properly. I've used them in a lot of industrial electronics designs and they've performed quite satisfactorily with excellent reliability. I didn't use them because they were cheap but because they were suited to the job. I've designed other stuff for which they wouldn't come within a hundred kilometres of what was required.
I chuckle when I hear people say what a great voltage reference the TL431 is. It's another part that is perfectly good for lots of things but it is a pretty low-end voltage reference. If I were still doing design I'd still be finding places where I'd use it, just as I would find places for the LM324.
I've been wandering around watching electronics videos on TH-cam. I'm not doing it to learn things, but to evaluate the quality of the information being put out by people purporting to teach electronics to others. The content ranges from very good to absolute rubbish, with lots of mediocre stuff with mistakes and poorly founded opinion. This channel seems to be a better grade of mediocre.
Fascinating, thanks for clearing that up.
On the "short bus," that is a great expression. Made me smile.
Thanks for the husbandry manual for these beasts of an opamps 😂
So if you're using two of them, you'd tie one output to +Vcc and the other one to -Vcc to balance the load on the power supply rails? Or would that not matter?
if that's important to you. many product power supplies have non-symmetric + and- supplies. the + supply may have more current capability than the -
@@IMSAIGuy gotcha, thanks
thank you Chinese, thanks to you we have a superb video. And a little thank you to you who didn't throw away your fake TL072s.
I love the 258, 258A (358) since it has ground sensing capability and single rail I use it for many things, Did you know that you can use the 358 as audio amp with a single rail configuration without crossover distorsion? I designed a small amp using single rail and it sounds great if you bias the chip correctly, however the weaker side of the 358 is that is has quite a bit of white noise when nothing is playing and I am trying to find a way to make this less if possible
Some of the noise will come from the amp itself and there's nothing you can do about that (other than use a lower noise opamp), but some might be Johnson noise from the resistors. Try redesigning the circuit to use lower value resistors and use decent quality metal film parts. But make sure the amp can supply the higher currents involved. It may be enough to eliminate some of the noise you're hearing.
@@RexxSchneider thanks for the input. I think most is coming from the amp itself in this case but as you say components can play a big role in sensitive circuits too. I will have this in mind when I keep work on this project next time :)
what are the design consequences of supply-referencing the output load? That would be interesting to know.
At least the TL072 has the same pinout as the LM358. I have a bunch of 8-pin opamps suspected to be LM358s but were relabeled by the Ebay seller as 741s. Wiring up a LM358 to 12V as if it were a 741 did not end well
My understanding is that its output stage is a Class B push-pull amplifier with the known crossover distortion which is fixed by placing two diodes in series between the npn base and the pnp base. Those diodes are missing in the LM358.
So they are not biased properly internally ?
@@andymouse It depends on what you think "properly" means.
If you directly drive both bases of complementary output transistors, then you will find a "dead band" where neither transistor is on. That is not quite Class B operation. If you add a couple of diodes between the bases and push current through the diodes, you might just find the point where both output transistors are just starting to conduct, which would be the ideal class B operation. Unfortunately, temperature changes and mismatches make that unrealistic, so we generally try to turn on both output transistors a little bit. That tends to eliminate the cross-over distortion caused by the "dead band", at the cost of significantly increasing the quiescent current consumption of the amplifier.
The LM358 has that dead band but has low quiescent current. It only takes one resistor drawing a few milliamps to ensure that at least one output transistor is turned on in applications where the dead band is unacceptable. The ability to choose between current consumption and linearity makes the LM358 more versatile, so I personally don't think there is anything improper about the internal biasing.
I bought an Italian greyhound - yeah right it turned out to be a chihuahua / daschund. Oh well - she's still my dog 8 years later!
This is e-x-c-e-llent content! Bravo! I would really like it, if you would explore cures for the known glitches on the XR2206 and AD8038 OEM Function Generator chips. Yes, they are ancient and not in production, but that is not the point. The cure is. Thanks.
In my experiance they are very tough and rugged work horses, cheap and reliable also.
I've designed the LM324 into all sorts of industrial electronics and they have performed well and reliably. The A version is worth the extra small cost sometimes.
I've designed test and measurement circuits in which the LM324 might find a place but is way, way, way out of the running in other parts of the instrument. It is all about selecting devices that are suitable for the application at hand.
@@d614gakadoug9 I have used them religiously in solar aplicaciones, and they have shows a huge resistance to static build up and esd, very rugged compared to more modern esd sensetive op amps and due to there low BW, they are generally very stable, not prone to turning into unwanted oscillators.
Is that right one can delay more and more its switching to another darlingtons group with bias resistance growth (like pnp being pushed away of common emitter rail). So it behaves like simistor with ground to rail bias controlling opening angle(delay).
How much correct this thought can be?
Like the videos
Care and Feeding. 😂 😆 😝
AFAIK, LM324 was one of earliest (the earliest?) quad op amp that could operate from a single supply. Does anyone know of an earlier one, that was as cheap and available. One chip instead of 4, and a single supply, was revolutionary.
Good thing I have lots of TL opamps 🙂
Can you put goes across to the negative rail or the positive rail it is acting like a Class A amplifier rather than a Class B when download goes to ground
I love the thumbnail. LOL.
Thanks for the video. 11:00 Actually most of the opamps do from Vee+2 to Vcc-2, while LM358 goes from Vee to Vcc-2. It's better in this respect, never worse. I'm not aware of opamp that "pull up well". Also could you please clarify your statement about single-supply and dual-supply op amps in the beginning of the video? From what I know an opamp doesn't care if you power it from +/- 6V or 0 and +12V. It's all the same from its perspective. You just need to bias input signals accordingly. This being said I used only widespread/cheap op amps in my projects like LM741 / TL081, NE5532, LM358, etc. So maybe I don't know something.
if you operate some opamps single ended and run them to ground they will actually invert and go to +V. I think the TI app note explains this.
Any op amp can be used with a single supply or dual supplies. The limitation in terms of practicality is how close the output can swing to the supply rails and the input common voltage range.
Amps designed for dual supplies generally have an output swing of something like 2 volts above the negative supply to 2 volts below the positive supply. That makes them pretty much completely useless in lots of applications unless you use dual supplies of adequate voltage.
The input common mode range can also be a significant problem with a single supply.There is more variation here, but it can be much like the output swing range - the amp will only operate properly with both inputs somewhere in that previously mentioned range. Amplifiers designed for single supply typically have a significantly different input stage that allows it to work right down to the negative supply voltage - zero volts. Of course with just a unipolar supply, inverting amplifiers can't be implemented in any case without biasing the non-inverting input at a voltage above the negative supply.
If you violate the specified input common mode range odd things can happen, and this is true for any amp, even if operated on dual supplies. The worst problem in many applications is "phase reversal." You might be increasing the input signal, going positive, and the output is happily following according to the gain, then suddenly the output goes negative instead of more positive. This is really bad new when the amplifier is being used in a control loop. It's like turning the steering wheel of your car to the right and suddenly the car steers all the way to the left. Some amps, especially more modern ones, are designed to prevent phase reversal even when the inputs are well outside of the range in which proper operation is assured. You can still fry the amp with excessive positive or negative input voltage if the current is limited to just a few milliamps.
Very good info!
12:12 Could you name that electronic load looking box to the left of scope?
th-cam.com/video/SoDIe6WD77k/w-d-xo.htmlsi=wdbCXOxOdbkgQA7h
Also your original starts failing before fake one. Attenuation start dropping first on original yet fake one keeps no voltage drop which seems to show fake is a better option
It’s not failing. It’s doing what it was designed to do. With the fake one it’s hard to know what you’re really getting.
Lets call this a 'chip of the day' which I like. ;-]
Everybody likes chip of the day !
oh yeah - it is now the meme of the day. will I ever live it down?@@andymouse
Tesco in my comments!!!! My tablet has AS. Artificial stupidity . It does this on posting. Rescued was the intended word.
Lol ! I just got back from Tesco !
Anyone who watches this video should read to app note, lest they get they get the idea that 358, 124, and 192 are weird garbage parts. All of these design choices were made to allow for low current single supply (often battery) use at a time when nearly all op-amps needed a +/- 15V supply and current could be fairly high. In addition, not being able to swing to the rails and phase reversal was a common headache with many op amps. This is a 40+ year old design by now...
amazing how they cheat us! hahaha. Thank you fun and interesting
A cheap part is a good part. Except when its an op-amp 😅
It can still be a good good part if you know what you are doing.
(I'm referring to a properly designed and made cheap amp from a reliable manufacturer, not the rubbish sold on ebay and the like)
@@d614gakadoug9 haha yes I was being a bit tongue-in-cheek. But at the same time how many hours of debugging ur circuit is the cost savings worth to you.. There are plenty of cases whee the trade-off makes sense
And when its an electrolytic crapacitor. Cheap caps are bad.
Special opamps require special "storage" 🚮
young punk,... ;-}
line the bottom of your bin with garbage op amps,... why bother?
Given how cheap an LM358 is to make, and how well it works if you understand how it works and how to use it - it has its uses, and is not garbage. The engineer designing it into an application may be doing garbage job, sure, but that op-amp is still doing the same job it did the day it was first introduced. You can buy it pretty much anywhere, too. So if you’re designing a kit or something that should be of appeal to people in impoverished areas, count on 358 being available, and design for it. Even fakes are often a 358 under the hood. When you need more performance than it can provide - sure, use other parts, but someone in rural India may not be able to get on of the fancier op-amps easily. And this is just by the way of an example, it’s not like rural India is special in that respect.