GB539626A - Improvements in or relating to stroboscopic lamps - Google Patents

Abstract

539,626. Discharge lamps. FERRANTI, Ltd., CHILCOT, A. L. and MILLER, J. L. May 25, 1940, No. 9237. [Class 39 (i)] A lamp-for use as a stroboscope supplied from a condenser which is charged from a d.c. source-has a coated cathode 3 in the form of a split cylinder enclosed in a glass cylinder 5 closed at one end; the cylinder 3 is of nickel and is lined internally with gauze whose interstices are filled with a mixture of caesium chloride and aluminium which releases caesium when a hotspot is formed. A nickel carbon-coated screening electrode 6 is placed above the cathode either within the glass 5 or if the latter is short the electrode 6 is carried at its top ; a bright nickel ring 7 is formed or attached to the bottom of the electrode 6. Inside the cylinders is a starter electrode 4 for providing an auxiliary starting discharge. The anode 10 is placed far enough to ensure a positive column discharge. The filling is neon at a pressure of 25 mm. The nickel cylinder forming the cathode may be carbonized on the in- and outside. Powdered glaze such as sodium borate may be added to the caesium chloride-aluminium mixture before placing within the gauze to improve its attachment thereto. The anode leads 11 may be taken out of the upper end of the envelope instead of through a glass tube 11 to the lower pinch. The starter electrode may have a spiral portion or a piece of gauze at its free end.