I always thought the LM747 (National Semiconductor) was basically a dual 741. It also includes the offset null for both opamps in the 14 pin package. I think I still have a couple of them from the 1990's. Thanks for the video.
But...the 747 was the only chip with that package connection configuration. Before dual and quad op amp footprints were standardized. Tl074 goes bad, swap with LF437.
"I usually put in a modern part when I see it". And then troubleshoot because the damned thing is oscillating. Bodge in 47 pf capacitors in the feedback loop to slow it down. Extra points if the capacitance of your scope probe is enough to stop the oscillation. Don't ask me how I know. ETA: Also extra points if your Asian vendor is selling a modern, faster part, labeled with the old part number.
used the lm741 in the metal can in a lot of aircraft communications systems around the late 70's early 80's, later on the LM1458 to save on space. the LM759 was a great higher power opamp that could drive headsets and radio inputs etc. This was before we went full digital and the fun went out of it, analogue routing and switching was easer to fix as you could follow the audio through the system. Digital audio went in to as audio signals FPGA and popped out all mixed together straight in to the headphone amp. So it was down to the firmware guys to work out the where the design error was and make a fix. still have quite a few metal can lm741's laying about from the 80's i do like the old chip of the day.
There is also a dual version of the Fairchild µA709: Motorola MC1437. Dual µA741: Motorola MC1458. High speed version of µA741: Motorola MC1539. High impedance versions: Raytheon RC4132, National LF13741.
Ah, the 741, the heart of the MXR Distortion + guitar pedal. Since the signal is intentionally being distorted, the low slew rate is part of the charm.
I replaced a lot of Thompson SFC2741 opamps that went faulty over time. almost always the failure was offset related, the offset would drift outside the adjustment range for the offset null pins to handle. Being in a TO100 package, I found you could run them rather hard, and put a clip on heatsink to handle the higher power dissipation. They were otherwise reliable, only the odd ones, despite being in an application where they ran ultra hot. Replaced a few OP22 that failed because of a shorted output, that needed to deliver +- 15V output, so they were run off 22V supplies, a little beyond the rating of a 741, but the Mil spec ones handled it a champ, just a clip on heatsink, and even would survive the shorted output, though I fixed that as well. Replacing the cheap plastic industrial connector with a 19 pin milspec connector, and matching socket, as the plastic one could easily be broken. Solid aluminium plug and socket, with bayonet latch, was a lot stronger. Plus of course no way to order an OP22 and get it in under a month, but trays of SFC2741 around, and also used to order 2N3773 transistors by the box of 1000, because there were a fair number of UPS units that used 22 of them per half bridge, and if one failed they all would catch fire before the fuse blew, or the 80A breaker tripped, depending on the revision of the power supply. Worst ones used a Semikron darlington block, around 2kg of copper and a 100A transistor pair on it, that would blow up nicely. Replaced with the same heatsink and 22 2N3773 transistors per side instead, as that is fixable. 1980's era FR4 PCB, with those so easy to lift traces. Plus 50uF 630VAC capacitors in the ferroresonant side, that would smoke and send out grey hot foam as they died.
Very, very cool to do these "zero point" sessions, that cover some real basics, stuff that folks doing just microcontroller stuff, simple I/O, programming, they don't get the basics of real electronics...
Well, personally i dont like and use them any more. If the application is very simple i use (again) old parts like LM324, LM358 and maybe even741 stype parts. If i want more there are lots of more recent parts about the same price than TL07x but with much better specs like rail to rail or useable for lower power supply voltage and even without the ugly phase reversal thing...
well I used to see a lot of uA741. Probably a different manufacturers version, TI must have absorbed them as they still have both LM741 and uA741 with different datasheets, but are they the same part? No time at the moment to compare them, over to you...
I think so, although 741 wasn't the first IC op amp, just the first massive success. Fairchild made the horrible µA702 and popular but temperamental µA709 first. Before those, they were called bricks because of their size
The μA741's were probably national semiconductor parts, maybe Fairchild...i still have the big red Fairchild TTL data book, and their 'gold' Analog parts data books! I've often thought that if software was as well-documented as these TTL parts were, we'd have more reliable software?
I could be wrong but I think the uA meant micro-amplifier and it was from Fairchild. LM was from National Semiconductor "Linear Module" and the DM from National Semiconductor meant "Digital module". Again if I am wrong happy for a correction.
*The LM1458: The Secret Dual 741 Op-Amp* * *0:16**:* The "dual 741" op-amp is actually the LM1458. While not explicitly marketed as such, the LM1458 is essentially two 741 op-amps in a single package. * *2:52**:* The LM1458 lacks the offset null capability of the 741. This is due to pin limitations in the dual package. * *3:39**:* The video demonstrates the functional similarity between the LM1458 and the 741. Using a test board, the host compares the performance of both chips with various input signals (sine, square, sawtooth, and sync pulse) and shows they behave virtually identically. * *1:43**:* The LM1458 is a common and widely available component. It has been used extensively in various applications and is a familiar part to many electronics repair technicians. * *3:00**:* The video aims to highlight the often-overlooked connection between the LM1458 and the 741. The host emphasizes that despite its different name, the LM1458 effectively serves as a dual 741 op-amp. I used gemini-1.5-pro-exp-0801 to summarize the transcript. Cost (if I didn't use the free tier): $0.03 Input tokens: 6975 Output tokens: 513
I always thought the LM747 (National Semiconductor) was basically a dual 741. It also includes the offset null for both opamps in the 14 pin package. I think I still have a couple of them from the 1990's. Thanks for the video.
YEP !
You are right, the dual '741 is '747 .
EXACTLY !
But...the 747 was the only chip with that package connection configuration. Before dual and quad op amp footprints were standardized. Tl074 goes bad, swap with LF437.
"I usually put in a modern part when I see it". And then troubleshoot because the damned thing is oscillating. Bodge in 47 pf capacitors in the feedback loop to slow it down. Extra points if the capacitance of your scope probe is enough to stop the oscillation. Don't ask me how I know.
ETA: Also extra points if your Asian vendor is selling a modern, faster part, labeled with the old part number.
used the lm741 in the metal can in a lot of aircraft communications systems around the late 70's early 80's, later on the LM1458 to save on space. the LM759 was a great higher power opamp that could drive headsets and radio inputs etc. This was before we went full digital and the fun went out of it, analogue routing and switching was easer to fix as you could follow the audio through the system. Digital audio went in to as audio signals FPGA and popped out all mixed together straight in to the headphone amp. So it was down to the firmware guys to work out the where the design error was and make a fix.
still have quite a few metal can lm741's laying about from the 80's i do like the old chip of the day.
There is also a dual version of the Fairchild µA709: Motorola MC1437.
Dual µA741: Motorola MC1458.
High speed version of µA741: Motorola MC1539.
High impedance versions: Raytheon RC4132, National LF13741.
Ah, the 741, the heart of the MXR Distortion + guitar pedal. Since the signal is intentionally being distorted, the low slew rate is part of the charm.
I replaced a lot of Thompson SFC2741 opamps that went faulty over time. almost always the failure was offset related, the offset would drift outside the adjustment range for the offset null pins to handle. Being in a TO100 package, I found you could run them rather hard, and put a clip on heatsink to handle the higher power dissipation. They were otherwise reliable, only the odd ones, despite being in an application where they ran ultra hot.
Replaced a few OP22 that failed because of a shorted output, that needed to deliver +- 15V output, so they were run off 22V supplies, a little beyond the rating of a 741, but the Mil spec ones handled it a champ, just a clip on heatsink, and even would survive the shorted output, though I fixed that as well. Replacing the cheap plastic industrial connector with a 19 pin milspec connector, and matching socket, as the plastic one could easily be broken. Solid aluminium plug and socket, with bayonet latch, was a lot stronger. Plus of course no way to order an OP22 and get it in under a month, but trays of SFC2741 around, and also used to order 2N3773 transistors by the box of 1000, because there were a fair number of UPS units that used 22 of them per half bridge, and if one failed they all would catch fire before the fuse blew, or the 80A breaker tripped, depending on the revision of the power supply. Worst ones used a Semikron darlington block, around 2kg of copper and a 100A transistor pair on it, that would blow up nicely. Replaced with the same heatsink and 22 2N3773 transistors per side instead, as that is fixable. 1980's era FR4 PCB, with those so easy to lift traces. Plus 50uF 630VAC capacitors in the ferroresonant side, that would smoke and send out grey hot foam as they died.
Very, very cool to do these "zero point" sessions, that cover some real basics, stuff that folks doing just microcontroller stuff, simple I/O, programming, they don't get the basics of real electronics...
One good thing about the 741 is that it rejects most RF interference in the audio amplifier. Sometimes less is more.
For some reason I have it memorized that the 1458 is a dual 741. Maybe Mims had it in his notebooks?
There is also a quad 741, the LM348 (LM148/248 too).
yes, for those interested: www.ti.com/lit/ds/symlink/lm148-n.pdf
It's WHY-dlar. For some reason he did not like being called Wee-dlar. I've always wondered if it was to distance himself from his Bohemian roots ..
I knew that from the past somewhere. I think Radio Shack sold them and the info that it was a dual 741 was on the package.
great video.
NJM4558 datasheet indicates it is a dual NJM741... Japanese equivalents to these opamps?
It should have been called the LM1482, if it is in fact 2 x 741.
They forgot to null out the offset.
TL071, TL072 & TL074 are all great too.
Well, personally i dont like and use them any more. If the application is very simple i use (again) old parts like LM324, LM358 and maybe even741 stype parts. If i want more there are lots of more recent parts about the same price than TL07x but with much better specs like rail to rail or useable for lower power supply voltage and even without the ugly phase reversal thing...
peace be upon you sir
Why do I sometimes see the micro symbol before the 741 like µ741? Is it because the first time they made it small?
well I used to see a lot of uA741. Probably a different manufacturers version, TI must have absorbed them as they still have both LM741 and uA741 with different datasheets, but are they the same part? No time at the moment to compare them, over to you...
I think so, although 741 wasn't the first IC op amp, just the first massive success. Fairchild made the horrible µA702 and popular but temperamental µA709 first. Before those, they were called bricks because of their size
The μA741's were probably national semiconductor parts, maybe Fairchild...i still have the big red Fairchild TTL data book, and their 'gold' Analog parts data books! I've often thought that if software was as well-documented as these TTL parts were, we'd have more reliable software?
It used to be that the prefix identified the manufacturer. µA741 was originally from Fairchild and LM741 was from National.
I could be wrong but I think the uA meant micro-amplifier and it was from Fairchild. LM was from National Semiconductor "Linear Module" and the DM from National Semiconductor meant "Digital module". Again if I am wrong happy for a correction.
The best number of 741s in a package would be zero...
They're are a lot better than an empty socket!
Naive.
Opamps had to start somewhere, they weren't too bad at the time, if you want really primitive I've got a PA230 around from the stoneage!.
*The LM1458: The Secret Dual 741 Op-Amp*
* *0:16**:* The "dual 741" op-amp is actually the LM1458. While not explicitly marketed as such, the LM1458 is essentially two 741 op-amps in a single package.
* *2:52**:* The LM1458 lacks the offset null capability of the 741. This is due to pin limitations in the dual package.
* *3:39**:* The video demonstrates the functional similarity between the LM1458 and the 741. Using a test board, the host compares the performance of both chips with various input signals (sine, square, sawtooth, and sync pulse) and shows they behave virtually identically.
* *1:43**:* The LM1458 is a common and widely available component. It has been used extensively in various applications and is a familiar part to many electronics repair technicians.
* *3:00**:* The video aims to highlight the often-overlooked connection between the LM1458 and the 741. The host emphasizes that despite its different name, the LM1458 effectively serves as a dual 741 op-amp.
I used gemini-1.5-pro-exp-0801 to summarize the transcript.
Cost (if I didn't use the free tier): $0.03
Input tokens: 6975
Output tokens: 513
i don't like how you move the paper, all around