Updated 09-15-2008

September 2008 Column



Vacuum Tubes, from the beginning?

Edison, 1885

Claude Paillard, F2FO, Today

1933 Experiment
50 Year Old Edison Lamp used in Receiver,
February 1933 issue of Radio-Craft, a Gernsback publication.

Left, Dr. Orestes H. Caldwell, and Dr. Clayton H. Sharp tuning the simple receiver with the 50-year old Edison tube.

Tube in-progress of being made

1933 Circuit used with Edison Bulb

The lamp has a carbonized bamboo filament surrounded by two upright thin wires which Mr. Edison used as the plate. The schematic circuit of the set is shown:
It is simple, and was run directly off the 1l0-volt D. C. line.

Actual Radio working with new tube

Added 9-15-2008

Click here. for The Blackburn Story

Another Film (Vintage 1960's) from the Blackburn factory in the UK, about 33 minutes long. The Blackburn Factory location has a long history in the manufacturing of valves. Click here for The Blackburn Story Tnx to Morris Odell.

Edison Bulb References

William J. Hammer Collection ca. 1874-1935, 1955-1957 #069
-Copies of The Edison Effect and Its Modern Applications by Clayton H. Sharp, 1921

Vacuum Tubes: History of Vacuum Tubes
In 1904, a British scientist called John Ambrose Fleming invented a device to convert alternating current signal (AC) to direct current (DC). This ‘Fleming Diode’

A Brief Biography of Thomas Alva Edison
The "Edison Effect"

The year 1883 was significant for Edison in that, by his discovery of what was to become known as the "Edison effect," he pushed aside a veil of darkness behind which wereed on the ‘Edison Effect’ which had been discovered by Thomas Alva Edison in 1880. to be found all the wonders of electronics. Edison in this achievement discovered the previously unknown phenomenon by which an independent wire or plate, when placed between the legs of the filament in an electric bulb, serves as a valve to control the flow of current. This discovery unearthed the fundamental principle on which rests the modern science of electronics.

In that year, 1883, Edison filed a patent on an electrical indicator employing the "Edison effect," the first application in the field of electronics.

The facilities of Menlo Park were proving inadequate to meet the requirements of Edison's amazing ability. He began looking around for a place more suitable for his needs. This he found in the little Essex County community of West Orange in northern New Jersey. He gave the orders that set workmen to the task of building a new and greater research laboratory.

Edison made this discovery known to Ambrose Fleming, the professor of electrical engineering at University College in London.

In 1904 Fleming tried an Edison effect bulb for this purpose, and found that it worked well to rectify high frequency oscillations and thus allow detection of the rectified signals by a galvanometer. On November 16, 1904, he applied for a US patent for what he termed an oscillation valve. This patent was subsequently issued as number 803,684 and found immediate utility in the detection of messages sent by Morse code.

Invention and Technology Magazine Fall 2002
Mark Wolverton - The tube is dead. long live the tube.
The Edison effect remained nothing but an oddity until the British scientist John Ambrose Fleming began experimenting with it early in the twentieth century. By 1904 he had developed the Fleming diode, which used the Edison effect in a vacuum tube containing two electrodes, called the cathode (or filament) and the anode (or plate). Applying electricity to the cathode, heating it, caused current to flow to the anode. Because only the hot cathode, and not the cool anode, gave off electrons, current could flow in only one direction. Fleming had invented a rectifier, a device to convert alternating current into direct current. The Fleming diode found immediate application in the detection of weak radiotelegraph signals.

Orestes H. Caldwell
The press release quoted Dr. O. H. Caldwell, editor of Radio Today, as saying that "each of the three notes is a rich tone with some harmonics which heighten the musical relish".

Caldwell, O.H. "The Radio Market." In Radio and Its Future, Martin
Codel ed.

Even members of the Federal Radio Commission got into the fray. Commissioner Caldwell stated that the "rider would wreck our present wonderful radio broadcasting structure" and claimed the amendment" is not practical and must be discarded in the search for a way to reduce the number of stations." Meanwhile the New York Times speculated, "(W)ill the Ides of March in 1928 go down in history as a turning point in 'radio'?

The Davis Amendment and The Federal Radio Act of 1927:
Evaluating External Pressures in Policymaking
Commissioner O. H. Caldwell stated: "Congress handed us a lemon and we have proceeded to make lemonade out of it."
1927 FED. RADIO COMM'N ANN. REP. 10-11. While dated "1927," the report was published in April 1928. This passage was from a speech given by Commissioner O.H. Caldwell to the National Press Club in Washington D.C. on April 30, 1927.

1935 The NY Electical society Mr. Orestes Caldwell, past President of the New York Electrical Society, gave a talk with slides on the development and practical application of the "so-called electric eye"


John Dilks, K2TQN    125 Warf Road, Egg Harbor Township, NJ 08234-8501   e-mail: K2TQN@arrl.net