Photo Cell Vacuum type mounted in the wooden box with aperture for light

A vacuum-type photo cell (phototube) is a laboratory device consisting of a vacuum-sealed glass tube with a photocathode and an anode inside. When light enters through an aperture, photons hit the photocathode's surface releasing electrons via the photoelectric effect. These electrons are attracted to the anode, generating a current proportional to the light intensity. The tube is mounted in a wooden box with a transparent or open aperture for light entry, providing environmental protection and easy handling for educational or experimental purposes.

This arrangement allows precise measurement of light energy based on the photoemission of electrons in a vacuum, useful in physics laboratories for demonstrating photoelectric effects and light detection principles. The vacuum environment ensures free electron travel between electrodes, enhancing sensitivity and accuracy.