What is a phototube?
Phototube, also known as a photoelectric tube, is an electronic light -sensitive device. It is designed to emit electricity when exposed to light or other form of electromagnetic radiation. The phototube got the nickname "Electric Eye" due to its use in a wide range of light sensing applications.
There are three categories of phototub: gas, vacuum and electrons multipliers. The basic phototrubice consists of a gas or vacuum electron tube in which two electrodes are mounted, cathode and anode. The gas phototube uses Argon or some other type of inert gas at very low pressure.
Electron multiplier is a modification of basic gas and vacuum photot run. In addition to two electrodes, this type of photot run is also equipped with a series of metal discs called dynodes. Dynodes are strategically arranged inside the electron tube to amplify electrical emissions.This coating is very sensitive to an ultraviolet, almost infrared and visible electromagnetic spectrum range. The phototube operates using a process called a photoelectric effect, while the light falling on the photo - --usitive surface causes the electrons to release from this surface. Through this process, when the surface of the cathode of phototruby is exposed to light, it releases electrons. These electrons are attracted by a positively charged anode and create electric current.
Phototrubice can be divided into three general categories of use: check, measurement and audiovisual reproduction. Light sensing applications, such as burglary alarm systems, automatic door opening, and traffic light control come under control. Measurement functions include their use in the color of pyrometers, while sound-visual reproductive applications include theater audio systems and tweezers.
withinFor example, the electrical circuit is used in a burglar alarm system and a light beam. The light beam is directed to a phototrubice that is installed at a certain distance. When the beam of light is interrupted, as if the door or window opens, the perimeter is broken. This can happen, for example, if the thief Jimmies opens the door. The broken circuit, in turn, causes a relay closing and the burglary alarm sounded.
In recent years, the photoelectric cells they use have been developed, using semiconductors rather than an electron tube. This caused in many cases the phototubice was obsolete. However, electron multipliers are still used for many applications.