Appliquéd Radio Circuits
May 1948 Radio-Craft

May 1948 Radio-Craft [Table of Contents] Wax nostalgic about and learn from the history of early electronics. See articles from Radio-Craft, published 1929 - 1953. All copyrights are hereby acknowledged.

Proving once again what a visionary Hugo Gernsback was regarding science and engineering, he published in his Radio-Craft magazine this prognostication for the eventual supplanting of point-to-point wiring with printed circuit boards. Admittedly, by 1948 the electronics industry had begun to outgrow hand-wired chassis assemblies with a rats nest of wires, components, and terminal strips. It was in dire need of a new paradigm that reduced labor costs and reduced the opportunity for wiring errors. Less than a year earlier (December 1947) the trio of engineers at Bell Labs announced their transistor invention, so Mr. Gernsback knew the world was about to change significantly. Bulky transformers, vacuum tubes, and high voltage circuits would soon be relegated - at least in the consumer product realm - to the newfangled television products, so miniaturization would follow quickly. Even the smaller fingers of women on the assembly lines would have difficulty working in such cramped spaces.* Hugo Gernsback predicted both metallized circuit traces and thick film "appliqued" traces on substrates.

* Somewhere I posted a story about manufacturers of all sort having preferred women for assembly work that required small fingers and high dexterity.

The next great radio advance is now in the making.

By Hugo Gernsback

There remains little doubt that the next few years will see a complete revolution in the building of our radio receivers, be they AM, FM or television.

It is certain that the wired radio receiver with its hundreds of wires and soldered connections will soon be completely outmoded.

The reason for this is elementary - from an economic standpoint wired and soldered radios are already dated, due to the tremendous labor costs. Then, too, receivers tend to become more complex as time goes on and the vast multiplicity of soldered connections no longer are workable. Servicing such sets is becoming more and more of a nightmare for that reason. Tracing circuits during trouble shooting is often a hopeless procedure and as the art progresses it becomes more hopeless both physically and economically.

At the present time top radio receiver manufacturers are racing toward the day when the wired component receiver will be replaced by something much simpler, which is cheap to assemble, and which will make servicing in the future a picnic - compared to our present receivers.

As reported in these pages repeatedly, the future receiver will either use a printed circuit in which the connecting wires are printed on a solid sheet of insulating material, or applied by some similar means. There are - and we mention only a few - the following:

Instead of printing the circuit it can be electroplated; it can be applied by the so-called silk screen process; or it can be done by spraying molten metal onto the surface.

Such new circuits also include the various resistors which are no longer solid blocks, but instead lines printed, sprayed, or applied to the surface by other means. An entire new art is springing up along these lines.

So far no "printed" radio sets have been produced for public consumption in the United States, but during the war there was great activity in this new art.

Dr. Cledo Brunetti, of the Bureau of Standards, outstanding exponent of printed circuits, produced many war radio sets where small size and guarantee of absolute performance were the prime considerations. These, however, were mostly along the miniature radio receiver lines. Standard receivers for home use, however, have so far not been produced.

In England one or two manufacturers have produced such radios, particularly those of the sprayed-circuit variety."

Up to now there has not been an all-embracing term in the English language which would do justice to this new and very important art. Not all circuits are printed, nor are they plated, nor sprayed. Yet they all come under the same general classification.

We therefore advance the term "appliqué" (from the French) - rhymes with bouquet. The English dictionary defines the term as follows: "Appliqué - decorative detail superimposed on a solid ground, as in 'appliqué work.' "

Similar terms are "appliquéd" and "appliquéing." This term is now being used in various industries, such as textiles for instance.

The nearest all-English term would be application - "the act of applying or laying on," but obviously this term cannot be used. We can use the new term in various ways as: appliqué radio receiver; appliquéd radio circuits; appliquéing a circuit.

The great advantage of these new applique receivers is the fact that most handwork is done away with. There are no soldered connections-everything either being screwed on, riveted, or fastened by other mechanical means. This means that-as is now done in England - an entire radio set can be made by a robot; i.e., a machine that does all the work from beginning to finish, delivering the complete chassis at the other end of the production line. No human hand touches the chassis while being processed. This cuts manufacturing costs tremendously.

The enthusiastic proponents of the new art foresee the day when the average superheterodyne chassis, minus tubes and loudspeaker, can be sold for $1.00 - certainly less than $2.00. The serviceman simply will take out the old chassis and discard it, replacing it with a new one. He will no longer hunt for hours to find a loose or intermittent connection - it will be far cheaper to install a new complete chassis with all its wiring, resistors, condensers, etc.

Some servicemen seem to think that this will ruin their business: Quite to the contrary, they will make more money because it will give them more time for installation and other radio work rather than wasting precious hours in hunting for open connections, blown condensers, burned-out resistors, and what not.

The future chassis will be light and small. It will weigh very little and will be completely foolproof. There will be few outside connections to be made tv it, such as tubes, loudspeakers, etc.

Moreover, the new applique radios will be equipped with miniature tubes, for which they are ideally suited. To show how the wind blows, we quote the remarks recently made by L. W. Teegarden, vice-president of RCA Tube Department:

"Today a large portion of RCA Tube Department production is assigned to miniature tubes. About 90% of all receiving tube developments is on miniatures."

Appliqué radios will bring down the price of all radio sets and particularly television receivers. At the present time only about 30,000 video sets can be manufactured a month. With appliquéd circuits, they can be manufactured by the hundred thousands per month, once the manufacturers have tooled up for the new art.

* See Radio-Craft, September, 1947, issue.

Posted November 19, 2019