Re: 555; was: Re: Who is your favourite electronics guru?

On 15 Aug 2006 16:53:27 -0700, bill.sloman@xxxxxxxx wrote:


John Fields wrote:
On 15 Aug 2006 06:26:40 -0700, bill.sloman@xxxxxxxx wrote:


John Fields wrote:
On 14 Aug 2006 18:00:06 -0700, bill.sloman@xxxxxxxx wrote:


John Fields wrote:
On 14 Aug 2006 15:33:49 -0700, bill.sloman@xxxxxxxx wrote:


John Fields wrote:
On Sun, 13 Aug 2006 16:01:38 -0700, Don Lancaster <don@xxxxxxxxxx>
wrote:


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

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

---
*** you Lancaster. Since when don't you _not_ have to climb that
learning curve in order to code and program the miserable little
thing?

As opposed to working out where you have to put the "magic diode" to
get the 555 to do what you want when the input and output polarity
don't suit your application?

---
Hmmm... It sounds to me like you're finally starting to learn about
the finer points of designing with 555s. Congratulations! Soon
we'll have another convert among us.

Not likely - you don't seem to be aware of the nasty side-effects of
the magic diode.

---
Well, even if that were true,

It's not only true but also obvious - put a diode in series with the
charging or discharing resistance, and the capacitor is effectively
ramping towards the rail voltage minus the - loosely toleranced and
temperature dependent - diode drop, which makes the monostable period
less stable and less predictable. Your switching thresholds are still
directly derived from the rails by those shoddy diffused resistors ...

---
To someone with an adequate command of the language my meaning would
have been clear, but for you I should have written:

"Well, even if it were true that I don't seem to be aware of the
nasty side-effects of the magic diode, you seem to think _you_ do,
so now you can use that knowledge to avoid the pitfalls you would
otherwise have encountered in your new career as a 555 circuit
designer."

Someone with an adequate comand of the language would have written

"Well, even if it were true that I don't seem to be aware of the
nasty side-effects of the magic diode, you seem to think _you_ ARE,"

---
Well, I can't disagree with that. It should have been an 'are'
instead of a 'do', but you obviously understand the context in spite
of your bluster.
---

What was actually posted was

">Not likely - you don't seem to be aware of the nasty side-effects of
the magic diode.

---
Well, even if that were true, you seem to think _you_ do, so now you
can use that knowledge to avoid the pitfalls you would otherwise
have encountered in your new career as a 555 circuit designer. "

Which does allow - in fact supports - the interpretation that you are
denying the nasty effects of the magic diode, rather than your obvious
ignorance about them

---
Not at all. From one who pretends to adequate communications
skills, the meaning should have been abundantly clear from the
context.
---

you haven't produced any quantitative comments
about the magnitude of the problem, which I would have expected from
someone who should have been incliuding it in his error budgets for
years.

---
Why should I? It would only come up if its use was marginal for the
application and, AFAIR, such wasn't the case for the application.
Matter of fact, the only reason you're kvetching about is because of
your recent and ongoing education about the vagaries of 555s and
your attempts to try to discredit me in any way you can, since I was
there before you were, LOL!
---

Get it now, Slow man?
---

Pity I'm not slow enough to miss your desperate attempt to recover your
lost credibility.

---
Well, Bill, at the end of the day I will have used a 555 in an
application that cried out for it and you will have used a 4047 in
the same application, which cried because you did, so I think it's
the slow recovery of your own credibility you ought to be concerned
with.
---

you seem to think _you_ do, so now you can use that knowledge to avoid the pitfalls
you would otherwise have encountered in your new career as a 555 circuit designer.

Since you seem to be blissfully unaware of the problem, I wonder where
you find your equally undiscriminating customers - this doesn't sound
like a party it would be safe to attend.

---
For you, definitely not! Someone might actually offer you work...
---

There are some customers who are more trouble than they are worth.

---
And some vendors.
---

People unsophisticated enough to be fobbed off with a 555-based design
are prone to developing unrealistic expectations.

---
Could be, but when push comes to shove and they look at your way VS
mine, I'll be working and you'll be wishing.


--
John Fields
Professional Circuit Designer
.

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