“Victor” cold cathode valve




                  The Victor Valve, similar in its internal structure to the Villard Valve introduced by the French Scientist Paul Villard (1860-1914), dates probably to the first half of the 2nd decade of the 20th Century. Because of the important difference in the surface size of the electrodes, the current passes much more easily in one direction than in the opposite one. Thus, when the large electrode, the aluminum spiral, is negative, a large flow of electrons passes towards the small flat electrode. On the contrary, when the latter is negative, its electron emission is low and the flow towards the spiral is negligible.


                  Using one valve in series with an x-ray tube cuts the inverse current and protects the tube. But the use of two valves, connected in series in opposite directions, between the induction coil and the x-ray tube as shown below (right) was highly recommended.


(Adapted from “Medical Electricity and Röntgen Rays”

3rdEd. by S.Tousey p.787, W.B.Saunders Co., 1921.)


                         Like x-ray tubes, rectifying valves were usually fitted with a regeneration device. The one in the above valve is of the asbestos fiber type.


                 When more power was needed, two or three valves could be used in parallel, and twin or triple valves were specially constructed for this purpose.




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