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| Why is the 741 op amp still produced? |
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| rdl:
If you've spent hundreds or thousands of hours testing, possibly over several years, to qualify something, then you really don't want to have to do that again because some component is no longer available. This is true no matter what industry you work in or what type of product you make. |
| alsetalokin4017:
I just bought 20 of them last week. Way overpriced at about 40 cents US each, but fast and free delivery and I didn't have to leave the house to go get them. They are marked like real ST UA741CN and look genuine on the outside. But I wouldn't know how to tell a fake except if it flat out didn't work, and my intended use case is very undemanding, I hope. I am still playing around with that Chaos Oscillator circuit from another thread. I first built it up with 2 358 chips but the original was done with 4 discrete single-chip opamps, not specified in the paper, but odds are they used 741. Also I have a bunch of vintage equipment, like my main bench power supply and an IEC signal generator, that has them scattered around in the circuitry in various places. I only had 2 remaining in my IC tin so I went ahead and ordered a handful to play with and for spares. |
| magic:
--- Quote from: alsetalokin4017 on September 21, 2020, 04:44:42 pm ---They are marked like real ST UA741CN and look genuine on the outside. But I wouldn't know how to tell a fake except if it flat out didn't work, and my intended use case is very undemanding, I hope. --- End quote --- One annoying sort of fakes are LM358 with false markings. Some are normal duals and likely to burn if you plug them into a single socket, others are rewired internally to work as singles. The latter can be spotted by having nothing connected to the offset null pins. A few people already scratched their heads over excessive bias current, noise or crossover distortion in what was supposed to be a TL07x or NE553x. |
| VooDust:
--- Quote from: Circlotron on September 18, 2020, 10:49:46 pm ---The 741 might have been a big deal in its day, but things have moved on. Nowadays we have a zillion different op amps to choose from, ranging from similar to vastly improved performance. I can’t remember the last time I saw one in a piece of equipment. And no one with a grip on reality designs them into new products. And even in the case of repairs for old equipment there would surely be modern substitutes available. And get this - I was looking at the TI 741 data sheet and it says the 741 “feature(s) improved performance over industry standards like the LM709.” The LM709 might indeed have been an industry standard fifty years ago but it’s a bit of a stretch to still refer to it as that. We’re in the age of GPUs with 28.3 *billion* transistors. It’s time the 741 was put to bed. It’s fine to read all about it from a historical point of view. That great, but I think school textbooks should stop using it as an example as if it were a mainstream device. But what to replace it with? Over to you. --- End quote --- Yeah it would be great if they stopped writing these "what are the essential op-amps" type blog posts where the 741 ranks on top. I would have gladly paid 50 cents more and get something that works rail to rail, thank you. For beginners anyways. |
| peter-h:
One would not design-in a 741 today, or anytime since about 1975, but it would be wrong to say the LM358 (which I've been using since c. 1975) replaces the 741 because - for a start - the output voltage swing is very different. There are rail to rail (on both input and output) op-amps but they are quite expensive. I have just done a design which needs to achieve 16 bit DC precision and a lot of the op-amps cost around $2 each. As a general comment, the world has moved many years ago from generic (and cheap, multi sourced) parts to high performance (and expensive, single sourced) parts. A clever designer will use the former, and they still exist. A lazy designer will use the latter, and keeps firms like Linear Technology in business :) |
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