Re: Who is your favourite electronics guru?


John Fields wrote:
On 10 Aug 2006 09:16:52 -0700, bill.sloman@xxxxxxxx wrote:


t.hoehler wrote:
"John Fields" <jfields@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:ut6md2lbcm82afti27scgj2rr28mr8l7gr@xxxxxxxxxx
On 9 Aug 2006 16:21:39 -0700, bill.sloman@xxxxxxxx wrote:


osr@xxxxxxxxxx wrote:

<snip>

It's a shame he won't walk around with 'some' chips on his shoulder!
<g>! Cmon sloman, get a few 555's, sit down at the breadboard, have fun!
Be bold, take a chance, get a 556, if you dare!

I did my playing with the 555 in 1975. I didn't like it much then, and
haven't seen any necessity to use it since.

---
So you've been out of the game for what... 20 years?

Come on, not even _one_ application?

Nothing where you could use a window comparator with a [pretty]
isothermal ratiometric voltage divider on its front end?

As it turns out - no. The string of three 5k diffused resistors is one
of the less attractive features of the device.

Nothing where you could drive a relay without having to use a
comparator and an outboard transistor?

Rarely had to drive a relay - we tended to design them out when we
could.

Nothing where you could implement a simple one-shot with a couple of
caps and a resistor or an astable with the same parts count?

We mostly designed out the one-shots as well, and the ones that I did
use tended to be a little quicker than the 555 could manage - there is
a paper in the Journal of Scientific Instruments - Ghiggino, K.P.,
Phillips, D., and Sloman, A.W. "Nanosecond pulse stretcher" Journal of
Physics E: Scientific Instruments, 12, 686-687 (1979) which describes a
discrete transistor monstable that stretches a 2nsec pulse out to
10nsec to make it detectable by an AM685 comparator - I should have
used an emitter-coupled monostable, but unfortunately the prototype
worked fine in the application, so there was no motivation to improve
it

Too bad your first encounter blinded you to what _was_ possible.
---

More made it clear to me what was impossible.

The only chip that I may have over-used would be the ICT7024
programmable logic device - its major virtue is that it plugs into a
22V10 socket, but offers some 20 logic cells, so you could salvage a
lots of bad designs with it back when 22V10's were popular, and it is
just big enough to be useful for (dumb) system-on-a-chip applications.

---
Back when 22V10's were popular?

Farnell still lists a page of them, but it has to be a legacy market.

As opposed to now, when you're grasping at threads?

If you are still using the 555, I suppose you are also still using
22V10's, and cutting up your food with knives you knap out of lumps of
flint.

It seems like what you're proposing is that there's now another chip
which can plug into a 555's socket and do a better job?

I'm proposing that there aren't that many applications where a circuit
designer who knows modern integrated circuits is going to end up with a
555-shaped space.

Got an example which can go the mile for the money?

That's the wrong question.

--
Bill Sloman, Nijmegen

.

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