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June 1949 Popular Science
 [Table of Contents]
Wax nostalgic about and learn from the history of early
electronics. See articles from
Popular
Science, published 1872-2021. All copyrights hereby acknowledged.
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No, this isn't about hallucinogenic
bath or ecstasy crystals providing a portal to Nirvana. It is an infomercial promoted
by Bell Telephone Laboratories (aka Bell Labs) that appeared in a 1949 issue of
Popular Science magazine. Soldering to glass or a rock (quartz crystal)
might seem like an impossible task; however, research efforts like this one described
by Bell Labs has produced many solder alloys and techniques which have led to robust,
reliable, electrically conductive processes used in many applications. Lead has
been used with glass for centuries in the form of stained glass windows, but its
primary requirement was to ruggedly capture the colored glass shards and to form
a watertight seal. Electrical connections, especially at high frequencies, require
a more exacting approach. Indium Corporation
has long made exotic solder available for unusual applications. I had one of their
Research
Kits way back in the mid 1980s when working on some classified projects at Westinghouse
Electric, which manufactured sonar systems for the U.S. Navy using ceramic crystals
for transducers.
Bell Telephone Laboratories Ad
 How would you solder a wire to a crystal?
This must be done for most of those wafer-thin plates of quartz used in electrical
circuits. They play a big part in the myriad-channel telephone system that utilizes
coaxial cables.
This is how Bell Laboratories scientists solved the problem: A spot of paste
containing silver is deposited on the crystal and bonded to it by oven heat. The
crystal is then vapor-plated with a thin layer of silver. Then a fine wire is soldered
to the spot by a concentrated blast of hot air. The result is a rugged electrical
connection to the surface of the crystal which does not interfere with its vibrations.
Sealed in glass tubes, the crystals are precise and reliable performers in the
telephone system. Each is a crystal gate to a voiceway, separating your conversation
from the hundreds of others which may be using a pair of coaxial conductors, at
the same time.
This spot of paste, this tiny wire, this puff of air are among the tremendous
trifles which concern Bell Telephone Laboratories in finding new ways to improve
your telephone service.
Above is a coaxial circuit crystal in its glass enclosure. At right the crystal
is shown, 3 1/2 times actual size, with connecting wires soldered in position. Weights
on wires reflect energy back into crystal, so cut losses.
Bell Telephone Laboratories
Exploring and Inventing, Devising and Perfecting, for Continued Improvements
and Economies in Telephone Service
| Bell Telephone
Laboratories Infomercials |
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