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Primal Ambrose Fleming Tube

Jacob Roschy Ernst Erb Jürgen Stichling Bernhard Nagel 
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Forum » Valves / tubes - Semiconductors » Tube development up to 1933 » Primal Ambrose Fleming Tube
Mario Coelho
Mario Coelho
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21.Jul.09 23:51

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Dear Radiophiles

I have here a picture of the primal tube. It is in a front page of a Portuguese publication (Boletim CEC Mars/April 1969).

The title in the bottom is : "Prof. Ambrose Fleming's original thermionic tube in 1904".

I think we have not this  image in Rmorg pages. Do you think that is important to open a page for it  and to upload this image after that?

Mario Coelho

This article was edited 21.Jul.09 23:53 by Mario Coelho .

Roy Johnson
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22.Jul.09 00:35

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Dear Mario,

Many thanks.   I have added it as Fleming_01.

The picture on the cover seems to be a photograph from the London Science Museum that also appeared in "Vintage Radio" and other publications, although rotated.    

  I have added a new colour picture from the Science Museum.

The caption to the picture reads:-

The invention of the thermionic valve in 1904 by John Fleming at the Marconi Company was a significant development for electronics and radio communication. The first transatlantic radio transmissions of 1901 threw up a significant problem: how to detect the incredibly weak radio signals at the receiving end. Fleming, inspired in 1904 by a 'sudden and very happy thought', turned to modified experimental filament lamps which he had investigated earlier, and found that they detected the high-frequency signals. His invention was a diode, the first in a line of devices which were to be a mainstay of electronics well into the solid-state era.

Please add any further information.  Very many thanks for raising this.

Regards,  Roy

Nikolaus Löwe
Nikolaus Löwe
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22.Jul.09 17:39

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Dear friends,

the pictured tube is in the posession of the Marconi Corporation. More pictures of it and two other, similar specimens can be found under

This web site is outstanding in design as well as depth of content. Check it out!



Mario Coelho
Mario Coelho
P  Articles: 454
Schem.: 409
Pict.: 1030
24.Jul.09 22:26

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Thank you Roy and Nikolaus for your kind replies.

I had not seen yet the Fleming_01 im Rmorg. Now I had. It is very  good indeed.

The website is  an outstanding site.

Thank you very much.

Best Regards


This article was edited 24.Jul.09 22:27 by Mario Coelho .