Dynatron

For the brand, see Dynatron Radio Ltd

The dedicated dynatron vacuum tube was invented by Albert Hull in 1918. It has three electrodes: a thermionic cathode, a perforated anode, and a supplementary anode or plate, and its characteristic curves have a region exhibiting negative resistance, which is the property desired.

Other early vacuum tubes with four or more electrodes not designed for the purpose had significant secondary emission from the anode, and, when operated with the anode at a lower voltage than another electrode, exhibited negative resistance and could be used as oscillators or for other functions. Later tubes had anodes treated to reduce secondary emission, normally an unwanted phenomenon, and were not suitable as dynatron devices.

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Other articles related to "dynatron":

Dynatron Oscillator
... A dynatron oscillator is an electronic circuit that uses negative resistance to keep an LC tank circuit oscillating ... Older valves make good dynatron oscillators ... This type of oscillator is commonly known as a 'dynatron' oscillator, though, technically, only the version using the tetrode valve is a true dynatron ...
Albert Hull - Industry - Experimental Work - Dynatron
... He invented the dynatron which had three electrodes a thermionic cathode, a perforated anode, and a supplementary anode or plate ... The secondary emission of electrons from the plate made the dynatron behave as a true negative resistance and so the tube could generate oscillations over a ...
Dynatron - Operation
... In dynatron operation the supplementary anode is maintained at a lower positive voltage than the perforated anode ... The secondary emission of electrons from the supplementary anode makes the dynatron behave as a true negative resistance, allowing it to be used to generate oscillations over a wide range of ... significant secondary emission operated in dynatron mode ...