Who is your favourite electronics guru?

"John Fields" schreef in bericht news: snipped-for-privacy@4ax.com...

I've seen one in a cheap switched power supply.

Actually, that last thing is *exactly* what I'm about to build. It might wind up with an ATtiny12, though. Does Kendrick's original controller use a

I've seen them used in power on reset circuitry, either on one iteration of the Apple II or one of the clones of the Apple II.

And of course, it was the Apple II that first used the 558 for a joystick controller.

But yes, in mass produced items, 555s are pretty rare. It's not really a surprise, given that oscillators can be made with other things, and so can single-shots (and especially that both can be made with common logic ICs).

It's prototype, hobby and small production run items that are likely to see them, because it is a versatile device and in those cases it may be easier to use a common part than add another device to the stockpile.

I might argue that the 558 was in the Apple II because the computer had hobby origins, and it appears in the "IBM PC" joystick controller simply because it had been done before. The same basic concept could be done with a quad op-amp.

Michael

"John Woodgate" schreef in bericht news: snipped-for-privacy@jmwa.demon.co.uk...

Time to light up this thread with some entertainment.

That may be your experience, but I've seen them in mundane products like electric fence chargers, and sophisticated medical products as well. Professional engineers use what is available, mass producible and cost effective. They MAKE MONEY for themselves and the company they work for. That is the meaning of Professional. Pure and simple. Any other connotation is just high brow horse shit. regards, tom

I find them all over the place, in many products, often used in some funky manner

That one is quite neat, A friend has an ET gauge based on silk stretched over a light frame, it gets heavier as it gets wet, then tilts and trips an IR interrupter. But it's screwed up by any wind. The 555 one looks like a good replacement.

This book by Hans Camenzind is a good read about the 555 and other analog tricks. Probably well known, but just in case:

Barry Lennox

The 555 always was and always will be a total piece of shit.

The baby PIC's blow it completely away on all counts.

No. When I'm wrong I do admit it - it doesn't happen often, but I've posted "sorry, I blew it" here on several occasions..

Your problem is that I'm not wrong, and you can't accept it.

The PIC always was and always will be a total piece of shit.

The baby AVR's blow it completely away on all counts.

martin

And because it was a 555, it was repairable. That's the one reason I have qualms about programming a micro to do anything that small; I'm introducing a nonreplaceable part (replaceable by me, but not by others).

Mostly. But they're not so good at directly driving, say, a 12V/100mA load.

Best regards, Spehro Pefhany

The Commodore 64 had two 555s in it, (not for the joysticks though) and I salvaged a dozen from some old commercial aircon control circuits. (I think they were driving pulse transformers that switched triacs)

You are the ass. You are infering the existence of a complete design from the circuit diagram presented in the book - nothing in the book suggests that the redesign has ever been taken to the point where it might go through a fab.

In that sense we never post complete designs here - we just post circuit diagrams illustrating the central idea or ideas, which is what Hans Camazind did in his book.

Mostly a reasonably skiled designer can get from there to a practicable design without having to rethink anything or retrace their steps, but that process uses up an appreciable number of hours of skilled labour.

If you happen to be the other partner in the dialogue.

We wasted a lomng time argueing about this, and you seem to have forgotten all the arguements.

Try and remeber the context.

Complementary inputs and outputs.

It was the first astable that came to mind ...

I worked as an electronic engineer from 1973 to 2003 for some eight different organisations. In two of the organisations I was the only electronic engineer, and most of the detailed design was handled by sub-contractors whom I had to supervise - 1992-93 and 2000-2003. I've got to meet and work with a great many professional engineers.

There have been quite a few design reviews. Some of the managers were idiots when it came to electronics, but most of the engineers were at least good, and some were superb.

Demonstrable competence in designing for low volume production, where the cost of the design is the biggest single itme in the total costs for the item over its entire life-cycle.

You, on the other hadn, are a Johnny one-note, who automatically optimises for relatively high volume production, and gets excited over a proce difference that represents a few seconds of design time.

I should be so lucky.

It isn't evident in the comments you post.

At a level you don't aspire to.

But this isn't evident in the stuff you post.

Well, the MC68HC908JL8 looks as if it is the world's nicest 8-bit processor with a built-in 8-bit wide multipler and 16-bit wide divider

- but (hardware multipy and divide apart) it is pretty much what I was working with in 1979, before British task division pretty much shut me out of the jobs they reserved for programmers. I've worked with instruments built around more capable computing hardware., and I can't say that I'm all that impressed - but I am deeply envious ...

Not hardware, microcode. That's why it takes 28 T-states to do a divide and 20 to do a multiply. That's not so much worse than the 8 minimum it takes to do an add, but there is a difference.

Best regards, Spehro Pefhany