December 1955 Radio-Electronics
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Electronics,
published 1930-1988. All copyrights hereby acknowledged.
Each month Radio-Electronics
magazine ran a column called "'What's New?," which contained a few products recently
introduced to the marketplace, production floor, research laboratory, etc. First
up was the introduction of wire wrapping as announced by Bell Telephone Laboratories
a couple years earlier (see Bell Labs full-page ads in
Radio & Television News in 1953). Wire wrapping is still used today for
quickly prototyping circuits that are not too sensitive to crosstalk and super high
speed. Next was the announcement of a five-transistor pocket radio from a Japanese
company named Tokyo
Tsushin Kogyo, which you know today as Sony. Heathkit had recently put out a
build-it-yourself analog computer that used 65 vacuum tubes for $750 ($7,342
in 2020 money). A button-hole-size transistor radio was also reported, along with
a stereo design and construction for build-it-yourselfers.
What's New? Circuit Connections, Biggest Heathkit, Japanese Transistor
Corrosion-resistant, solderless connections which are expected to provide trouble-free
joints for the whole life of the equipment on which they are used are made by a
new machine developed by Bell Laboratories. The connections are made by wrapping
six turns of wire around rectangular terminals. The wires bite into the terminals,
with a pressure of about 15,000 pounds per inch at each contacting area. Photo above
shows a board wired by the new method compared with a conventional wiring job. Inset
shows how the wired connections look, and the arrow points to one of them. The Bell
machine is programmed with a tape and can wire up a whole circuit board of the type
shown above, stripping insulation from the wire ends, wrapping them around the correct
terminal, then proceeding to the next as instructed by the tape. The method has
also been used with hand-controlled tools.
Japanese Transistor Portable
New Nipponese five-transistor radio compares very favorable with American receivers
of similar size. It has two i.f. stages, two audio stages, converter and uses two
diodes for detector and a.g.c. Maximum output is 100 milliwatts, and output at 10%
distortion 50 milliwatts. The power supply is four penlight cells (6 volts). Either
a 2 1/2-inch dynamic speaker or an earpiece can be used. Transistors are made under
Western Electric license, and the company, Tokyo Tsushin Kogyo, is putting out a
class-B seven-transistor model at an early date. The seven-transistor job is rated
at 100 milliwatts maximum output and 50 milliwatts at 10%, using a class-B output
This job is an analog computer in kit form for use of schools, laboratories and
research organizations. The kit will sell for around $750, contains 6,000 parts,
65 tubes, 5 relays and 35 diodes. Extending the principle of the slide rule to the
log-logth power, it is expected to be a valuable means of training future engineers
and to permit universities and small industries to investigate projects previously
impossible because of the length of time required to make the computations.
Miniature Radio at Last
A buttonhole-size FM radio is announced by Glen Ecker, California inventor. Hardly
a cubic inch in dimensions, this little FM receiver actually does pull in stations.
Performance is not to be compared with that of larger sets, but is surprising for
one subminiature tube. With a pair of headphones in place of the single earpiece,
the reception can be said to be on the entertainment level. The set uses a superregenerative
circuit, and detection is by the slope method, in which the set is tuned slightly
off the signal to be received. Tuning device is a compression-type mica trimmer
capacitor. The power supply is a penlight A cell and a 30 volt battery, which are
mounted on the plastic tile shown in the photograph above.
Hi−Fi Do It Yourself
Enterprising owner of the Audio Repair Service, Miami, Fla., found a way to cash
in on the "great deal of free information" he was called on to provide customers
building their own audio equipment. Facilities and tools are provided and advice
given the audio constructor - at a fee which the builder considers nominal and which
turns the former liability into a profit. "Any type of audio service work may be
undertaken in our shop, even cabinetry," says Vic Randel, the owner. "Work is supervised
to a successful conclusion and the cost remains nominal. Local hi−fi dealers look
on the idea as a means of promoting sales, and it even proves a stimulus to our
own service work."
Posted November 24, 2020