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


"Michael Black" <et472@xxxxxxxxxxxxxxxxxxx> wrote in message
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"mc" (look@xxxxxxxxxxxxxxxxxxxxxxxxxx) writes:
<bill.sloman@xxxxxxxx> wrote in message
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John Fields wrote:

Most requests on these groups don't ask for, "How can I program a
microcontroller to do this or that?" , they ask for a circuit which
can do what they want to be done and which can be built with glue
logic and discretes.

And you come up with a 555-based solution - to the man with a hammer,
everything looks like a nail.

And if a nail works, why not? The 555 is a very handy gadget for
implementing small, simple control circuits.

Having said that... 555s in commercial products appear to be rare.
Offhand
I can only think of one instance. The original IBM PC gameport used a
558
(quad 555) to sense the joystick potentiometers by determining how long
it
took to charge a capacitor.


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).


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 ***.
regards,
tom


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