MEET
MR. FET...
the transistor
that thinks it's a tube
By LOUIS E.
GARNER, JR.,
Semiconductor
Ede'
THIS
LITTLE FELLOW
AND
HIS
FAMILY ARE
TAKING
OVER
SOLID -STATE
IT'S
HARD to
imagine, in the
light
of
present
scientific
and
technological
achievements,
that just
a few short years
ago
there were
no transistors and
no in-
tegrated circuits.
In fact,
there are
still
many
old- timers
who remember the
"prehistoric" age
when there were no
vacuum tubes, either.
In
those days,
radio
transmitters
were
weird
spark
-
sputtering
electromechanical monsters
which bore a
nostalgic resemblance to
the
fire
-eating dragons of a yet earlier
era.
Radio receivers
were
simple,
too.
A
huge antenna hooked up to
a couple
of
oversized coils, a tiny
bit
of
mineral -
galena -with
a
cat's whisker (
fine
wire) ,
a pair
of headphones . . .
and that was
the receiver.
The
galena, a crystal
de-
tector,
was cheap, but it was insensitive
and temperamental,
too.
It
was on a
quest for
a better detector
that
Prof.
J.
A. Fleming
developed the
diode
vac-
February,
1967
uum tube
which, rightly enough, came
to
be known
as the "Fleming
valve."
A
short time later Dr.
Lee De Forest,
inventor
and scientist, added
the control
grid
which, for the
first
time,
enabled
the
vacuum tube
to amplify, oscillate
and detect electrical
signals.
With
the development of the vacuum
tube
came a giant
industry
with a rec-
ord
of spectacular achievements
in ra-
dio broadcasting,
electronic
surveillance,
computer technology, and industrial
con-
trol.
During
the course of this
industrial
revolution,
the
vacuum
tube
was en-
larged, miniaturized,
modified and
refined
in many
ways,
including
the addition of
more electrodes. But
there was a pro-
verbial
fly
in
the ointment.
Most
tubes
generated
so much heat that
they had a
relatively
short useful
life,
and this re-
sulted
in
a high
failure rate
for
tube -
type
electronic equipment.
Then,
early
in 1948, Drs.
Shockley,
Bardeen,
and Brattain
-all
scientists at
the Bell
Telephone Laboratories-an
-
nounced
the invention of
a completely
new
device :
a
triode
"crystal"
which
they claimed could
amplify as well
as
detect
electrical signals. Dubbed
a
47
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