Rail to Rail output stage for 2A 5V

John Larkin wrote in news: snipped-for-privacy@4ax.com:

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The key is the analysis of the event.

As long as all parties are ever conscious of all the elements involved. One gains knowledge by good, strong observational skills. Always good to make detailed observations of both as designed operation and failure modes thereof.

Afterward, toss them a nice 2kV cap charged up. Keep 'em on their toes. The only real danger would be if they used both hands for the catch, and the leads happened to match up with one to each hand and allow for a short term 'across-the-body' 'discharge event'. Naah...

That's really sick. The only thing I toss my co-workers is chocolate truffles.

The Brat was captain of the Cornell softball team. She casually reaches up and plucks flying objects out of the air. I never could catch things.

I never related to that. While others in school wanted to destroy everythin g, I fixed things. I learnt electronics from nothing through fixing things. The formal qualifications later didn't add much. So I had some nice things , a growing collection of testgear & pocket money, they had nothing.

NT

What, no explosives, capacitor discharge banks, nitrogen tri-iodide, bricks tossed at picture tubes?

Now that I'm almost grown up, I like to find out what the real abs max limits are on parts. Sometimes it's 3x or 5x what's on the data sheet. Sometimes the data sheet just doesn't say.

That's engineering research, not kids blowing stuff up.

On a sunny day (15 Jun 2019 16:45:03 -0700) it happened Winfield Hill wrote in :

I have not blown up things in decades, except my WiFi booster on the wrong power adaptor some month ago (careless). And propellers of my drone, flying into trees, while testing auto-pilot software.

It makes little sense, if you want to sell something at the edge of breakdown, so out of spec, the risk is that it WILL breakdown. Repair by others becomes difficult, the next new part they buy may fail immediately. Manufacturing tolerances and changes.

I like to repair stuff. The art of designing is to make things that last. I know the art of profit is to make things with limited lifetime from light bulbs to cellphones...

As a kid, in highschool, worst I did was put a bottle with some stuff that reacted and after some time popped a lid from pressure with a bang under the teachers desk.

Some other kid had his own chem lab at home, made rockets...

hing, I fixed things. I learnt electronics from nothing through fixing thin gs. The formal qualifications later didn't add much. So I had some nice thi ngs, a growing collection of testgear & pocket money, they had nothing.

I used to fix those TVs. Before the brick not after :) I fixed some crazy s tuff as experiments. CRTs with zero emission, a very nice TV half crushed & mostly underwater, burnt out stuff, a TV with an entire board missing, etc etc.

My first thermostatic soldering iron was found crushed. The handle must hav e been in 20 or 30 pieces. Soon had that going. TVs, batteries, stereos, vi ntage lighting, all sorts of history pieces, you name it. Most people spend decades paying for everything they want in life. Why? Because it never occ urred to them to learn useful life skills, or to do something more useful t han watch tv.

I did some of that in my teens. Didn't like it when things broke though. So my data was based on minimal sample sets. Soon found you could get way mor e from mains transformers at limited duty cycle. And some ICs. and... a lot of things.

NT

It makes sense to know where that edge is.

On a sunny day (Sun, 16 Jun 2019 03:09:46 -0700) it happened John Larkin wrote in :

Sure, datasheets say that too:-) The problem is for repair people who will replace with the same component number. The manufacturer will have made a new run and is still within specs, but the poor repair guy will be stuck, very expensive for buyers!

I would not allow that practice.

That's excessively severe, there are many important aspects that datasheets don't deal with at all, and others where they completely fail to do their job.

Paul and I have been collecting certain kinds of parts for about 40 years now, and we have made sets of measurements to see how much "typical" parameters drift with time, and presumably with process changes. We have also repeatedly tested say 100 pieces from a batch. What we've found is often there's a very high level of matching in a batch, and the decade-to-decade drift is often remarkably low. It's worth investigating. There's much to learn beyond the datasheet info.

On a sunny day (16 Jun 2019 06:15:37 -0700) it happened Winfield Hill wrote in :

Sure investigate anything you want. I was reading those MOSFET specs you recently published here, very interesting. But using things out of spec is a nono in many fields. I sure hope Boeing does not work that way. In broadcasting if you can find the error in 15 minutes and replace the transistor and it then blows up again, the hourly cost of a studio full of artists, many of whom can only be contracted once, is mind boggling. There is almost always some redundancy, but time is limited, complexity is enormous. Real world is different from a lab setting where you can just tinker all day to get it right. We had a very high quality acceptance lab, not sure they would accept the practice if they knew about it. And then we are talking about equipment that costs a quarter of a million dollars a piece and that was years ago. Not that accepted things did not break down, or did not need modification, that happened all the time, but in consensus with the manufacturers. Bad practices are better avoided.

That's probably where I went wrong, then. Another dumb thing I did when young and stupid was to try to make nitroglycerine. I saw this episode of Casey Jones where Casey and his crew have to *delicately* transport several kegs of TNG over the railway to some mining site where the miners are all trapped underground by a rockfall and need to be blasted free. I already had some 70% concentrated nitric acid in my collection; just had to go to Boots to get some glycerine and I was away. It didn't quite work, though. When I dropped a tiny amount from a test tube onto the ground like the guy in Casey Jones had done, it didn't violently explode; just fizzed like soda. Fortunately, I was unaware at that time of the importance of sulphuric acid to the reaction or I wouldn't be typing this now. I had some 98% sulphuric acid "in stock" at that time too! Sometimes ignorance protects you. :)

We found a big paper bag full of shotgun shells in the closet of a vacant house. We had fun that summer.