الملفات المحرضة او المحرضات - الرسوم التخطيطية للدارات الالكترونية .. الإلكترونيات

Exciting coils or inductors - Schematic diagrams of electronic circuits .. Electronics

Exciting coils or inductors

The exciting coil is a number of languages ​​of insulating wire around a cylinder or a gate of insulating material (41). The inductance of the coil can be increased by increasing the number of turns or increasing its diameter, or by using an iron core inside the coils to concentrate the magnetic field lines. The inductance of the coil that contains a small number of languages ​​(142) is very small, while its value increases in the coil that contains a larger number of turns (42b). The coil may have points of contact between them, or it may contain several coils placed next to each other on the same cylinder (42c). In the case of a large number of coils, the coil is divided into several sections (42d), and in this case it is called a "high frequency generator" because it obstructs its passage.

Special materials such as ferrite or iron are usually used in the manufacture of the cores of these coils to increase the intensity of the magnetic field and its concentration in the core of the coil used in the radio frequency, and to increase its inductance as well, which can be adjusted precisely using a threaded iron core that can be moved inward or outward, as needed (43). Such a coil is symbolized by

41 - Coils and inductors
42 - Other small inductors

The variable inductance and the moving iron core are represented by the symbol shown in the figure, which is a coil with a dotted line and a diagonal line next to it. The dotted line indicates the presence of the iron core, while the diagonal line that cuts the coil indicates that it is adjustable. Usually, magnetic cores are not shown in circuit diagrams, in order not to complicate them.

Low frequency coil cores

The cores of the coils used in low frequencies are made of different alloys (44). In the past, thin strips of iron were used. The coils are usually wound around insulated reels that completely surround the core, except for its middle leg, which is placed inside the core, which is made of thin metal strips that take different shapes and dimensions to manufacture them according to need.

This inductor is called a "low frequency choke" because of its ability to impede their passage. Such a choke is used to get rid of the ripples resulting from the rectification processes of the source current or the power current entering the device, and therefore it is called a "leveling choke" or "smoothing choke". The inductance value of the coils used in low frequencies is estimated in several Henrys.

43 - Changing the inductance value by means of an adjustable core.
44 - A large inductor with a core made of iron strips.