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| Is the 555 still a viable IC? |
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| Psi:
--- Quote from: EPAIII on February 18, 2024, 12:36:41 am ---Consider, if you built a circuit with a 555 timer 50 years ago, which is still in use and the chip went bad, you could just get another 555 and drop it in and the circuit would still work today. About a one hour repair, including the time spent ordering the new 555. If you built a circuit with a micro processor 20 years ago and the chip went bad, that micro processor would probably not be currently available. You would probably need to build a completely new circuit with either an "improved" version of that processor or with a completely different one and then wonder where the original code was. Oh, that's right, your IS department replaced the desktop where the code resided 10 years ago and they don't keep back-ups for over 5 years. So you would wind up re-writing the code from scratch. So in order to save a few pennies and use the latest and greatest technology, 20 years ago, you wind up spending several days building the new circuit and writing the code for it and testing, of course. Now, tell me which would have been a better choice. --- End quote --- Yep, speed of repair and maintenance is very important, especially with fixing production test jigs or any production line equipment where down-time is expensive. Not having to worry about firmware is a big time saver. Not just because of the time required to code and flash it but having to test it and any regulatory or procedural hoops required to change it. On the other hand having a MCU makes diagnostics easier as you can easily add hardware checks and warnings in code to quickly diagnose and find faults. So it depends on the situation and is often a trade-off |
| Smokey:
I've only done one design that used a 555. I needed an adjustable frequency and duty square wave that would be user settable with pots to drive a pneumatic valve as an air burst thing for machining. While it "worked" it's fiddly to adjust since the duty and frequency are not fully independent. I should have just used a micro. |
| johnboxall:
They're easy, you can find success without much effort which is great for education. |
| baldurn:
As a counter argument against the 555 I have observed that nobody here at the local makerspace would use the 555. The typical hobby person is doing Arduino or ESP32 for everything. People tend to solve everything with the one tool they know, so the 555 does often not even get considered. We do have some classes where we play with old chips, and where we might do something fun to learn the 555 - but the day after everyone are back with their ESP32 project. Funny that you say software development is the reason to avoid a MCU and use 555. These days most people think the other way around. We go with a MCU even when a 555 would have done the job. It is easier to figure out a simple program than it is to do "real" EE with discrete components. |
| SiliconWizard:
--- Quote from: baldurn on February 18, 2024, 02:39:56 am ---Funny that you say software development is the reason to avoid a MCU and use 555. These days most people think the other way around. We go with a MCU even when a 555 would have done the job. It is easier to figure out a simple program than it is to do "real" EE with discrete components. --- End quote --- Yes. That is, until people actually have to make stuff that is provably reliable - that's usually when they reconsider doing everything with software. But for tinkering, it may look easier. |
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