Cover

The sketch on this issue's cover (Radio-TV Experimenter, Volume 6, 1958) represents an experimenter in the process of constructing a vacuum tube Tesla coil. One of the articles in this issue shows a circuit for a vacuum tube Tesla coil. However, this one takes on a new twist.

TCBA member John Freau has built a vacuum tube oscillator that can be varied to give discharges that show characteristics of a spark oscillator and vacuum tube oscillator as well as somewhere in between.

The setting for the spark oscillator type discharge actually produces a machine gun-like tat-tat-tat. John refers to this condition as the “staccato mode.” John Freau's experimental work has been quite extensive and this project is but one example of his talent. (see “Vacuum Tube Tesla Coil in Staccato Mode.”)

Revelations: Book 15, Verses 15 - 8

The title to this report does not refer to the New Testament of Christian Theology according to King James. But it does refer to the Tesla coil bible according to Richard Hull.

Included in this issue is an extremely valuable report on certain principles of Tesla coil operation and techniques for their application. Although some of what you will read has appeared in previous issues of the newsletter written by Hull, much of what he tells us here are revelations of the most important kind.

The major point of the article has to do with the importance of large terminal capacitances. Hull tells us not only the “why” of terminal capacitances but just how much is needed. In between the “why” and the “how” is an encyclopedia's worth of valuable data. (see “Optimization of Tesla Resonator Coil Performance Through the Use of Massive Terminal Loadings”)

When Is a Choke Not a Choke?

This issue also carries an article which poses a question about R.F. chokes. TCBA member Herman W. Flynn has done some experimenting with chokes and found the results somewhat puzzling. Perhaps some knowledgeable readers will respond to Mr. Flynn's article.

The Science Museum of Virginia

Richmond, Virginia is not only the home of the TCBOR, it is also a city with a science museum that houses a Tesla coil. According to one report, the coil is housed in a metal cage and is capable of discharges 60 cm long. The museum is located at 2500 W. Broad St., Richmond, VA 23230. (tip from R.G. Kent)

Dedication: H. Armagnat

This issue's “Tesla Coils Resurrected” column includes the second installment on Tesla coils from The Theory, Design, and Construction of Induction Coils by H. Armagnat. This section includes a portion on “Resonators” (more on this subject in the next issue). Armagnat begins this part by crediting Nikola Tesla with introducing the resonator. And as far as I am aware, this is one of the few instances where Tesla has been acknowledged as the inventor of the single-ended high frequency coil.

The book was published in 1908 and one wonders if anyone took notice of Armagnat's declaration. If you review any of the electrical books and periodicals published after 1908, you will see that the single-ended high frequency resonator is credited to Dr. Paul Oudin. Was Armagnat's book banned from libraries?

Incidentally, this book is a translation. Translation from what - French, German, etc.? I'll guess it is from the French language. And one must wonder about Mr. Armagnat's first name. I looked through all of my periodicals of that era and even a book review from the Electrical World. All referred to the author as H. Armagnat. I'll guess its Henry. Does anyone have information on this matter?

Regardless of whether I am right or wrong, this book contains one of the most complete bibliographies of any books on the subject of induction coils (25 pages). Anyway, it's not a title you'll easily find. Perhaps the book had a small distribution is the reason why Armagnat's countryman, Oudin, received so much credit for something Tesla accomplished. It is suffice to say that Armagnat should be recognized for correctly recording historical achievements in electrical discovery.

Edison's Miracle of Light

On October 23rd, a television program “Edison's Miracle of Light” was broadcast over PBS television stations. “There's no doubt that Thomas Alva Edison invented an electric light that burned for 40 hours. But Edison made several critical errors which were quickly exploited by his fierce competitors, the brilliant young scientist Nikola Tesla and businessman George Westinghouse.”

Although heavily biased in Edison's favor, the program made several references to Tesla and included some photos. It was pleasing to see Nick given some positive recognition for his contributions.

The only part of the program which caused me to wriggle in my chair occurred when Edison's name was mentioned while a motion picture of Niagara Falls was being displayed on the screen. The association gave the viewer the impression that Edison had something to do with the development of Niagara power. Of course, it was Tesla's system that conquered the great falls.