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A Opto Cell(phototube) is a vacuum glass tube device that utilises the photoelectric effect to generate an electron current and amplify signals.

A phototube is a photoelectric conversion device, also known as a photomultiplier tube or microtube. It functions as a highly sensitive electronic amplifier that employs the photoelectric effect to generate an electron current and amplify signals. Internally, the phototube incorporates a series of complex structures, including a photocathode and a collecting electrode circuit, designed to convert light energy into an electron current signal.

The operation of opto cell is based on the photoelectric effect. When light strikes a metal surface, the metal absorbs photon energy and converts it into electron energy. If the photon energy exceeds the work function gap between the electron-hole pair in the metal surface, high-energy electrons overcome the barrier, escape the metal surface, and form an electron stream. This constitutes the photoelectric effect.

Within the phototube, the photocathode serves as the metal surface. When light strikes the photocathode, electrons are emitted from the metal surface via the photoelectric effect. These electrons are accelerated by the accelerating field and continuously collide with surrounding electrons, creating a cascade of electron amplification that amplifies the signal. Ultimately, the electron current signal passes through the collector circuit, where it is converted into a measurable output signal.

Phototubes exhibit high sensitivity, rapid response, and low noise characteristics, rendering them extensively utilised in radio, communications, computing, and medical fields. Within radio technology, phototubes serve in high-frequency amplifiers, spectrum analysers, and measuring instruments; in computing, they are employed in scanners and image sensors; while in medicine, they feature in X-ray detectors.

The opto cell(phototube) is a highly sensitive electronic amplifier that generates an electron current via the photoelectric effect to amplify signals. Its internal structure comprises a photoconductive cathode and a collection circuit, among other complex components, offering broad application prospects.