Home:  Miscellaneous: COLD CATHODE OR TRIGGER TUBE, 1950's


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Cold Cathode tube loosely referred to as a trigger tube, used in electronic calculators having three elements a cathode anode and trigger element.
The tube fires and glows when a voltage is applied to the trigger when a negative voltage is on the cathode and a positive voltage on the anode.
The tube will only extinguish if the anode voltage is removed.
Many devices can be connected in a line (10) for counting application, as in Sumlock Comptometers 'Anita' Calculators, used in the 1960's. The early computers of the 1940s and 1950s used the mature vacuum tube technology of the day. In the 1950s and early 1960s transistors were new and undergoing rapid development.
They were also expensive and prone to failure if badly treated electrically.
So it is no surprise that the first commercially successful electronic desktop calculator used vacuum tube technology.

Your comments:

  • The Ministry Geiger counter of the fifties, the "Meter - Contamination - No1", once common on the surplus market, used about seven of these devices, some of them complicated ones. They were all on the all-glass B7G and B9A bases.

    In the 1980s, the Russian attempts at producing aircraft equipment which would withstand the "EMP" - the electromagnetic pulse produced by a high-altitude nuclear explosion and intended to cause terminal failure by overload of earth-bound and aircraft electronics - used quantities of specially-developed versions of these miniature wire-ended tubes, and also many ruggedised miniature wire-ended vacuum tubes.
    .......... Anthony Bullock, Gloucestershire, England, 23rd of April 2011

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