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SUCCESS IS
ALL ABOUT YOU
at GENERAL
ELECTRIC'S
UTICA PLANT
There's an air of success and vitality
about General Electric's Light Military
Electronic Equipment Department
that's inescapable.
The demand for new ideas, new products
is tremendous . . . the department
is expanding to keep up with it
. .. and engineering advancement is
the order of the day.
Red tape, stuffiness and stereotyped
thinking are alien here; and there's
no place for the timid thinker or the
"born follower." But if you're an
engineer with a hunger for leadership,
this is where you're meant to be.
Starting Salaries Up to
$12,000
There's satisfaction -right up to your
very doorstep. Part of the enjoyment
of the job will be living in Utica, an
attractive city of 100,000 at the gateway
to the Adirondacks.
THINK IT OVER -and if you feel
your thinking matches the kind we do
here, get in touch with us for more
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OPENINGS Now in:
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MR. A. C. d'HOOSTALAERE
Light Military Electronic
Equipment Department
GENERAL
ELECTRIC
French Road. Utica, N. Y.
of more than 5 ma. may be drawn
through a 1500 ohm load. In general,
the insulation must be able
to withstand 900 v. tests, temperatures
are restricted to under 90 °C
at any point on the overall enclosure
or 65 °C on thermoplastic cabinets.
Specifications are somewhat modified
by input wattages and voltages,
details of which are found in the
appropriate specification. Tests are
also provided which may be used as
guides to materials or constructions
not fitting directly the prescribed.
The endurance of radio receivers,
even domestic ones, requires a little
consideration of the effects of
humidity, temperature, and dust.
With the introduction of portables
having connective circuits printed
on plastic decks (see Fig. 4) the
problem has become somewhat more
acute (the interlock for shock protection
of the exposed live printed
wiring may be noted). In Fig. 6 is
indicated the seriousness of the
combined effect of dust and moisture
on a printed circuit; the insulation
resistance between two parallel conductors
being notably decreased,
even though a coating of protective
varnish has been applied to one
sample. This problem has only recently
been realized and while several
types of coatings are being tried
no recommendation can yet be given
because of the limited amount of
field reports. The results here indicase
the inadequacy of MIL fungus
varnish for this purpose. Martin'
and Weinberg have also reported
on the inadequacy of some styrene
coatings, vinyls, phenolics and
epoxies tested under the MIL -E-
5272A humidity cycle. When said
coatings were below 5 mils thick,
all dropped to between 1 and 10
megohms but some hope was expressed
for epoxy if 35 mils or
heavier.
It should be recognized that in the
foregoing specifications the demand
for protection is based upon presumption
not only of deterioration
but inadvertent connection to
sources higher than intended voltage,
or through line surges or lightning.
If a printed circuit is to be insulated
by an overcoating, presumably
this also will have to withstand
the 900 v. test.
The problem of protecting printed
circuits and general impregnation of
wiring is discussed more fully below,
except that printed decks, because
of low heat conductivity, have
frequently been found to have temperature
requirement exceeding that
of insulated wire and equal only to
the problem of bare wire.
(To be continued next month)
rti
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TITLE
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Tele -Tech & ELECTRONIC INDUSTRIES June 1956 For product Information, use inquiry card on pages 209 -210 363