Nova Patents
US2809366A

Device comprising a gas discharge tube

Abstract

This record has no abstract on file.

US2809366A, drawing sheet 1
Sheet 1 of 4

Term

Term ended

Expired 8 October 1974, 52 years ago.

  1. Priority
  2. Filed
  3. Granted
  4. Expired
  5. Today

7 claims: 3 independent, 4 dependent

  1. 1
    What is claimed is:1. A circuit arrangement comprising a gas discharge tube, said tube having cathode and anode electrodes and an ionizable filling, a source of potential, said tube being ignitable alone by the application of a potential above a given value, means for applying across said cathode and anode electrodes a potential below said given value and at which said anode is positive and said cathode is __ negative, and means for heating the positive anode to a οδ temperature at which ions are produced therefrom to ignite the tube.
  2. 4
    A circuit arrangement comprising a capacitor and p means including a rectifier having cathode and anode °° electrodes for charging said capacitor to a high D.-C. potential, one terminal of said capacitor being at a negative potential and the other being positive, the positive terminal being connected to the cathode of said rectifier, a gas-filled discharge tube having a cold cathode and a 79 thermionic anode connected in parallel with said capacitor, said thermonic anode being connected to said 2,809,366 DEVICE COMPRISING A GAS DISCHARGE TUBE Henricus Johannes Joseph van Boort and Pieter Klaas Euijs, Eindhoven, Netherlands, assignors, by mesne assignments, to North American Philips Company, fee., New York, N. Y., a corporation of Delaware Application July 6,1954, Serial No. 441,538 Claims priority, application Netherlands July 8,1953 8 Claims. (Cl. 340—75) The invention relates to a device comprising a gas discharge tube to which is applied a voltage which is not capable of igniting the tube at the prevailing pressure and electrode spacing, this tube being ignited by other means. The invention relates, moreover, to a gas discharge tube for use in such a device. It is known to reduce the ignition voltage of a gas discharge tube by heating the cathode to a temperature such that electron emission is obtained. As an alternative the ignition voltage may be reduced by exposing the cathode to light radiation of short wavelength or by exposing the discharge path to beta- or gamma rays. However, it is not always desirable or possible to carry out these methods, since a suitable current source for heating the cathode or a a suitable source of radiation may occupy tco much space or be too costly or may fail or give rise to other drawbacks. The invention has for its object to provide a device comprising a gas discharge tube which is ignited by a method differing from the aforesaid known methods. According to the invention, in a device comprising a gas discharge tube, to which is applied a voltage which alone is not capable of igniting the tube at the prevailing pressure and electrode spacing, the ignition is obtained by heating the anode to a temperature such that ions are emitted. An aperiodic discharge requires heating of the anode 40 only for a short time, i. e. until the tube has ignited. Since ion emission requires comparatively high temperatures, comparatively high power being supplied during the heating. In order to further the emission of ions, the anode may be activated by means of alkaline earth metal oxides or other substances emitting ions. However, at the required high temperatures a strong vaporisation of the activating material may readily occur. Consequently both with respect to economy in energy and lifetime, the heating of the anode should not last for a longer time than is required to ignite the tube, unless the discharge is only transient. With alternating-current discharge lamps for example it is known to preheat the two electrodes of the lamp, the discharge being initiated subsequently by a voltage pulse. However, the temperatures at the electrodes of these lamps are so low that no appreciable ion emission from a heated electrode connected as an anode can occur. The field prevailing between the electrodes is, in itself, not sufficient and, on the other hand, a high temperature will, in itself, be neither sufficient to produce the ignition. The invention will now be described with reference to the accompanying drawing, in which:Fig. 1 shows a device for producing luminous flashes having a steep front and Fig. 2 shows the discharge tube used in this device. Referring to Fig. 1, reference numeral 1 designates a battery which feeds through an interrupter or switch 2 a vibrator 3, which in turn drives a hi-voltage transformer comprising a primary winding 4 and a secondary winding 5. A rectifying tube 6, having an anode 7 and a 2,809,368 positive terminal of said capacitor and said cold cathode being connected to said negative terminal of said capacitor, said D.-C. potential being insufficient alone to ignite said discharge tube, and means for passing current through said thermionic anode to heat the latter to a temperature at which ions are emitted thereby, whereby the tube is ignited and the capacitor discharged therethrough.
  3. 6
    A device comprising a gas discharge tube having an ionizable filling and a cathode and an anode, and a circuit for igniting said tube comprising means applying a high D.-C. potential insufficient to ignite said tube across said cathode and anode and at which the anode is positive relative to the cathode, and means for heating the anode to a temperature at which ions are emitted thereby to ignite the tube.
Independent claims3