Technical means of restricting the penetration of unwanted persons into the protected area are increasingly being used to improve the safety of homes and industrial premises. Among them, intercom systems that allow you to remotely control visitors and control their access are popular, and their designs are constantly being improved.

The device and the intercom operation scheme are created for specific consumer requests. They differ in the principles of construction, elemental base, installation, maintenance, operation technologies. The following principles are used in the work of doorphone circuits that monitor and control people's access: creating a closed area with the possibility of restricting visitors from using technical means based on automatic locking devices, organizing communication points ...

Active lightning protection is an electrical system that serves to artificially accept and discharge lightning current into the ground. The active lightning protection system is triggered when dangerous thunderstorm activity threatens with its natural development of a specific protected area. The system is ahead of its self-development and the formation of a lightning discharge in a natural way, and thereby protects a vast territory, much larger than conventional lightning protection methods.

To better understand how active lightning protection works, we turn to the basics of the theory of the occurrence and development of lightning and the principles of the organization of lightning protection systems. What is lightning and what is lightning protection? In general, linear lightning is an electrical discharge in the atmosphere resulting from growth ...

Accumulators in electrical engineering are usually called chemical sources of current, which can replenish, restore the consumed energy due to the application of an external electric field. Devices that supply electricity to the plates of the battery are called chargers: they bring the current source into working condition, charge it. To properly operate the battery, it is necessary to present the principles of their work and the charger.

A chemical recycled current source during operation can: supply the connected load, for example, a light bulb, an engine, a mobile phone and other devices, spending its supply of electric energy, consume the external electric energy connected to it, spending it to restore the reserve of its capacity. In the first case, the battery is discharged, and in the second it receives a charge. There are many battery designs ...

Non-contact thermometers or pyrometers are today convenient devices for remote temperature measurement of various objects, liquids or solids. They are widely used in the power industry for the operational control of the temperature of important areas, in the electric power industry to ensure fire safety, in laboratory conditions, in enterprises, in construction for calculating heat losses, in everyday life, in security systems, and much more.

The first such device was invented back in 1731 by the Dutch physicist Peter van Mushenbrook, and the measurements were made visually, it was possible to judge the temperature of a red-hot body. But modern types of pyrometers have greatly expanded the scope of their application, and even measure temperatures close to zero degrees Celsius and below. However, the principle remained generally the same ...

In many electrical appliances, the principle of implementing secondary power has long been applied through the use of additional devices, which are entrusted with the function of providing electricity to circuits that need power from certain types of voltage, frequency, current ...

For this, power supplies are created that convert the voltage of one type to another. They can be built into the consumer’s case, like on many microprocessor devices, or they can be made as separate modules with connecting wires on the model of a conventional charger on a mobile phone. In modern electrical engineering, two principles of energy conversion for electric consumers are successfully coexisting, based on the use of analog transformer devices for transmitting power to the secondary circuit and switching power supplies ...

A single-phase electric motor is called one that works from a two-wire AC network, represented by a phase and zero potential. The number of windings mounted in various designs of stators does not affect this definition. According to its technical device, an induction motor consists of a stator - a static, fixed part, made by a housing with various electrical elements located on it and a rotor rotated by the electromagnetic field of the stator.

The mechanical connection of these two parts is made by rotation bearings, the inner rings of which are mounted on the fitted sockets of the rotor shaft, and the outer ones are mounted in protective side covers fixed to the stator. The rotor device for these models is the same as for all induction motors: on a steel shaft mounted magnetic circuit from burdened plates based on soft iron alloys ...

Plasma in physics is the fourth state of matter after solid, liquid, and gaseous forms, when partial or complete ionization of the medium from previously neutral molecules and atoms occurs under the condition of quasineutrality: the volume density of all charged particles is equal.

The welding technique uses the following properties of low-temperature (less than a million degrees Kelvin scale) plasma: very high electrical conductivity, the strong influence of external magnetic fields on the flow of currents in it, contributing to the formation of jets and layers, the manifestation of collective effects, manifested by the predominance of magnetic and electric forces over gravitational. In this welding method, the source of heating metals to the melting point is a plasma arc of ionized gas, which is directed in the right direction. It is produced by a special device ...

Ways to control fixtures without the use of stationary switches are increasingly gaining popularity among the population. This is due to the ease of use and widespread availability of kits for sale, which make it quite easy to switch existing chandeliers to remote shutdown or inclusion.

Manufacturers have now massively mastered the production of original luminaires with LED lamps and garlands that create beautiful lighting effects while saving energy. They can be used without rising from a chair or sofa using a small remote control.

The basis of the remote control is the transition from traditional switches located on the walls of rooms and connected by wires to the chandelier and the apartment panel to the use of radio control channels.To do this, apply: a radio transmitter mounted in a small remote control ...