Photoelectric cell is a device which converts light energy into electrical energy. Photoelectric cells are of 3 types:
Photoemissive cell: It consists of an evacuated glass vessel containing two electrodes which are connected to a battery. The cathode is covered with some photosensitive material. The anode is a thin rod of platinum. When light is made to fall on cathode, photoelectrons are emitted and are attracted by the anode, causing photoelectric current to flow.
Photovoltaic cell: No battery or any other external source is needed in this case. When light is allowed to fall on a layer of cuprous oxide coated over a copper plate, photoelectrons are emitted and they start traveling towards the silver film which is coated over cuprous oxide.
Photoconductive cell: The principle of photoconductive cell is based on the property that conductivity of a semiconductor increases with the increase of intensity of incident radiation.
Photoemissive cell: It consists of an evacuated glass vessel containing two electrodes which are connected to a battery. The cathode is covered with some photosensitive material. The anode is a thin rod of platinum. When light is made to fall on cathode, photoelectrons are emitted and are attracted by the anode, causing photoelectric current to flow.
Photovoltaic cell: No battery or any other external source is needed in this case. When light is allowed to fall on a layer of cuprous oxide coated over a copper plate, photoelectrons are emitted and they start traveling towards the silver film which is coated over cuprous oxide.
Photoconductive cell: The principle of photoconductive cell is based on the property that conductivity of a semiconductor increases with the increase of intensity of incident radiation.
No comments:
Post a Comment