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Old August 18th 03, 05:36 PM
R J Carpenter
 
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"Michael Black" wrote in message
...

But when building with
an IC, you will have to actually build something around it in order to
get something useful.

SNIP
thirty or so years ago, when
people would write to the magazines and complain about so many ICs
being used, and about how the internal diagram of the IC was not shown.
A lot of that could be discounted as a transitional reaction, that
since ICs were new people were reacting to the newness rather than
an absolute reaction to ICs being "cheating".


Over 30 years ago I homebrewed a PDP-8 work-alike computer. It was based on
the PDP-8 instruction set. I've never seen PDP-8 electrical or detailed
logic diagrams. I used ICs, but none more complex than a 4-bit adder. The
7400-series was then too expensive for me, so I used a cheaper compatible
Signetic series in most cases. My choice to use ICs was based on a desire to
finish the project within a reasonable time - which I did. There would have
been too many parts going all-discrete. Of course discrete transistors were
used as lamp drivers, to drive the core memory select lines, and in the
voltage regulators.

At least thirty years on, it's hard to imagine that there are people
who haven't adapted.


Even using simple digital ICs, you have to know a little about the internals
of the family to avoid pitfalls - and to interface to other families. Analog
ICs require more understanding.

SNIP

On the other hand, there is validity in constantly thinking through

whether
something should be done with transistors or ICs.


Or with a $2 microcomputer. IMO, evaluating the trade-off between hardware
and software is just as important. Where should one draw the line?

My hobby RF experience has mostly been limited to VHF frequency converters.

OTOH I assembled the first FM-stereo broadcast station in the Washington DC
area, WHFS 102.3 MHz. The "components" were rather large: an HH Scott stereo
generator, an RCA "iron fireman" FM exciter, and a 1 kW power power
amplifier that had seen service a number of other places. I built a
frequency-multiplier / IPA between the exciter and the 4-400 finals, and the
power supplies including that for the finals. I built the stereo audio
console for the station; my memory is a little hazy after 40 years, but I
think the console used some audio ICs.

SNIP

But these are design decisions, not some rhetoric about how everything
must be made from scratch. Any time something is designed, it's important
not just to look at the way to do it, but at other alternatives, because
people often do get blocked by looking down only one path.


As someone else said, engineering is making what you want from the parts
that are available.

73 de bob w3otc