It consists of cathode C, and collector C, enclosed in an evacuated glass bulb B.
The cathode C is photosensitive surface. The electrons emitted are drawn to the collector 'C,' which is maintained at a positive potential with respect to emitter 'C,\ The photoelectric current can be read from the galvanometer
A device which detects or measures radiant energy by measurement of the resulting emission of electrons from the surface of a photo cathode.
The photo emissive cell, known also as photo tube, first appeared in the early 1920. These cells are familiar as the "electric eyes" that trigger the automatic opening of doors when a person intercepts a beam of light. These cells can also be used in a way similar to those of photo conductive cells, in order automate and control systems. They are used in astronomy, in the form of photo-multiplier tubes, to measure electromagnetic radiation from celestial objects.
A photoemissive cell is constructed with a wire anode and a semi-cylindrical cathode with an emitting surface, sealed in an evacuated or gas-filled bulb. As cathode surfaces, mono atomic layers of cesium, potassium, or rubidium are used. Due to photons that strike the cathode, and therefore transfer their energy to the surface electrons, some electrons can overcome the binding force and be emitted into space. These emitted electrons are attracted to the positive anode as a photo current of micro ampere order. For many applications, photo tubes were placed by semiconductor photo diodes.
(i)Photo-emissive cells:
In this device light strikes the cathode and interacts with the electrons in the metal where by the entire energy of light quantum is converted in to the kinetic energy of the electrons.
The photo emissive cell, known also as photo tube, first appeared in the early 1920. These cells are familiar as the "electric eyes" that trigger the automatic opening of doors when a person intercepts a beam of light. These cells can also be used in a way similar to those of photo conductive cells, in order automate and control systems. They are used in astronomy, in the form of photo-multiplier tubes, to measure electromagnetic radiation from celestial objects.
A photoemissive cell is constructed with a wire anode and a semi-cylindrical cathode with an emitting surface, sealed in an evacuated or gas-filled bulb. As cathode surfaces, mono atomic layers of cesium, potassium, or rubidium are used. Due to photons that strike the cathode, and therefore transfer their energy to the surface electrons, some electrons can overcome the binding force and be emitted into space. These emitted electrons are attracted to the positive anode as a photo current of micro ampere order. For many applications, photo tubes were placed by semiconductor photo diodes.
(i)Photo-emissive cells:
In this device light strikes the cathode and interacts with the electrons in the metal where by the entire energy of light quantum is converted in to the kinetic energy of the electrons.
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