In article , W7TI
writes:

On Wed, 22 Oct 2003 23:40:05 GMT, "Ken Finney"
wrote:

The semiconductor industry is one of the most bizarre there is, but it
works for them.
_________________________________________________ ________

Before semis became ubiquitous, tube manufacturers did about the same
thing. Any idea how many variations there are on the good 'ol 6AU6?
I'd guess probably between 50 and 100, some pin compatible and some not,
and not one of them worked a bit better than the others. But it was a
money maker for them to keep coming out with "new" tubes that everyone
had to stock up on.

In February, 1953, I did my first QSY on HF with a BC-339 that ran a
pair of 833s in the final. 833 is not your run-of-the-mill receiver set
tube. :-)

About the same time a group of the guys at Army station ADA were
into an argument about "how many vacuum tube types" there were
then. (I guess it was something to do) Several scarfed up catalogs
and things, even got the station OIC interested. I forget the exact
number but it was like 3500 nomenclature types of all kinds, receiving,
transmitting, power control, photoelectric eyes, whatever.

By 1960 there were the 12 V filament versions of basic 6 V tubes
and the other "weird" filament voltages for series-stringing to
reduce the cost of a transformer in a TV set. Ruggedized versions
of basic lower-power tubes for mobile and airborne were out with
5000 and 6000 series numbers. Loctals were disappearing as
were the "acorn" types for VHF-UHF. Big changes everywhere,
not just on TV sets, to meet both competition and new environments
and frequencies. Sylvania's tube spec book had small loose-leaf
pages, at least two update sets per year...:-)

By 1980 the number of available-on-the-market semiconductors were
at least two orders of magnitude greater than that old 1953 group
compilation of tubes done at ADA...maybe three orders of magnitude.
All kinds of ICs for many, many purposes and universal applications
like the all-purpose Opamp (bless you, Bob Widlar, wherever you are).

By 1990 there was already a trend of "downsizing" semiconductor
product lines. National Semi and Motorola data books were no longer
expanding beyond their one-foot shelf width for most volumes. There
was COMPETITION on the world market for all kinds of electronics
and it was fierce and hot, not just in PCs+peripherals but all kinds of
electronic things and products. The number of available semi products
had expanded beyond reasonable capitalistic bounds and the market
overall just couldn't sustain all of them.

Ahhhhh, the good old days.

Bill, I respectfully give you a pthbtbtbt on that. :-)

I DON'T want them back now that the whole electronics world is
swimming in a sea of wonderful parts plethora! Sure, it's getting
to be a chore on selecting a precise IC or transistor...because there's
SO MANY to choose from. In 1956 one was lucky to get a transistor
(affordable) that would work beyond audio frequencies.

Just got a Mouser paper catalog a couple days ago. It's a full inch
and a half thick with very thin paper contents. The Digi-Key industrial
catalog on paper is about that size, maybe larger. HUGE inventories!
Pages of semiconductor components that don't seem to stop. All
kinds of semis, all kinds of other components...TTL expanded to many
families, CMOS functional work-alikes to TTL numbers for zilch power
drain...voltage regulators, band-gap voltage references more precise
than zeners, all kinds of FETs capable of POWER handling, RF
transistors capable of working at 1.2 GHz, small signal FETs
approaching that. Huge selection of Microchip microcontrollers that
anyone can use and program with free software, displays that knock
the eyes out, LEDs of many colors.

Yes, the traditional "radio" parts aren't there anymore, not in the
Allied or Newark catalogs either. "Plate transformers" are hard to get
and only specialty places still sell variable capacitors for "tuning."
Even vacuum tube sockets are getting hard to get. The electronics
world get very big everywhere and it got much lower in voltage and
much bigger in functions for all kinds of purposes. Times change.

These are times of paradise for designers! I wouldn't have it any other
way... :-)

Len Anderson
retired (from regular hours) electronic engineer person