flicker-photometer

A flicker photometer is a device used to compare the brightness of two lights. It operates on the principle that when two lights of different colors alternate, the flicker is least noticeable when their brightness is equal.1

Photometers, in general, are instruments that measure the intensity of electromagnetic radiation, including visible light. They often convert electrical current into a mechanical reading, such as a pointer on a dial. These devices can utilize components like selenium cells or cadmium sulfide cells, whose electrical properties change in response to light. Photometers have diverse applications, including photography, measuring glare, and as components in more complex scientific instruments.2