Improvements relating to constant-light sources

Abstract

Abstract 719,899. Photo-electric cell housings. CASELLA (ELECTRONICS), Ltd. Sept. 8, 1953 [Sept. 10, 1952], No. 22745/52. Class 40 (3). [Also in Group XXXV] An electric lamp 8, e.g. serving as a light source for particle counting apparatus described in Specification 714,350, is mounted in a housing 8<SP>1</SP> associated with a projection lens 8<SP>2</SP>. Variations in light intensity of the lamp, detected by a photocell 9 mounted in a housing 9<SP>1</SP>, are corrected automatically (see Group XXXV). Between the lamp and the photocell are a heat resisting glass 15, an exchangeable filter 16, and an adjustable shutter 17 which facilitates selection of the optimum photocell operating point.

Inventors

• 👤 Ernest William Meyer
• 👤 Allen Edward Fitzsimmons

Bibliographic Details