Electric choke: why do you need a device, the principle of operation of the element and scope

An electric choke is an element used in various electrical appliances and radio devices. It regulates the amperage by separating or limiting electrical signals of different frequencies, eliminating DC ripple. By passing a current through a twisted conductor, a magnetic field is generated, which is used in electrical and radio engineering.

Principle of operation

The choke operates on the principle of self-induction. In appearance it resembles an ordinary coil, working like an electric transformer, although the structure consists of only one winding.

The choke coil has ferromagnetic or steel plates, insulated from one another to eliminate the formation of Foucault currents, which are characterized by high noise. The device acts as a restraining barrier in case of voltage drops in the mains.

But this particular device belongs to low-frequency ones. The alternating current flowing through the networks is characterized by a wide range of fluctuations: from 1 to 1 billion Hertz.

They are conventionally divided into the following types:

1. Low frequencies (they are also called sound) have oscillation boundaries of 20-20,000 Hz.
2. Ultrasonic: from 20 to 100 kHz.
3. Super high: over 100 kHz.

For devices operating at high frequencies, the core is replaced plastic frames or resistors, serving as the basis for winding with copper wire. In this case, the choke transformer is equipped with multiple layers or sectional winding.

The main technical characteristic of a choke coil is inductance (the accepted units of measurement are Henry (H), the resistive ability direct electric current (the amplitude of oscillations approaches zero) by changing the voltage within the required limits, by nominal magnetization current.

Using magnetic cores, the dimensions of the chokes with the same existing inductance values ​​are significantly reduced. The use of ferrite and magnetoelectric compounds, due to their small capacity, allows them to be used over wide ranges.

According to their intended purpose, coils of this type are divided into three types:

1. Alternating current - are applied to restrict it on the network.
2. Saturation coils - in voltage stabilizers.
3. Smoothing the ripple of the equalized current is weakened.

Magnetic amplifiers - chokes work with a magnetizable core under the influence of direct current. With its other parameters, the inductive resistance changes accordingly.

There are more three phase coilsused in certain circuits. Nowadays, various engineering problems are solved using various types of chokes.

Choke application

Inductance has found wide application in a wide variety of electrical, automation, and radio engineering devices. Chokes work in the form of various electrical filters, converters of electrical energy, different types of electromagnetic relays, as well as transformers. If the capacitor performs the storage function of an electric charge, then the inductance accumulates electromagnetic energy. That's why a choke is needed.

Through the passage of electricity through the wire, a constant magnetic field is generated. It depends on the number of turns: the more there are on the inductor and the more current passing through it, the stronger the element's magnetic field becomes. To increase the power of the electric magnet, a ferromagnetic core must be built into the device. The ability of a choke to generate a magnetic field is often used in electromagnets with high power, in various electromechanical relays, electric motors, and also generators.

The choke coil passes a constant electric current with a minimum resistance, but if a variable frequency current passes, it offers great resistance, that is, it acts as a filter. This ability, called inductance, is used to separate the variable frequency circuit from the constant frequency circuit. A steel core choke is used in line rectifier power supply filters to smooth out AC ripple.

Under the influence of an alternating magnetic field on the coil, an alternating electric current is formed in it. This inductive property is used in AC and DC electric generators.

They convert mechanical energy into electrical energy:

• hydroelectric power plants use the energy of falling water;
• generators operating on liquid fuel, when burning gasoline or diesel, generate electricity;
• thermal power plants use coal or natural gas as fuel;
• in nuclear power plants, mechanical energy is obtained by heating water.

When electricity passes through the choke, an alternating magnetic field arises around it, exerting an effect on a nearby coil and a variable electric current.

In this case, the coil acts as a transformer, which serves to equalize the load resistance with the internal resistances of the device that generates electricity. Transformers are used in all branches of telecommunications, all kinds of automated systems, radio engineering, various electronics, etc.

Electronic analogs

Inductive coils are usually quite large. To reduce them without changing any technical characteristics, it is necessary to replace the inductive element. Instead, it is installed semiconductor regulator. It performs the function of a transistor with a fairly high power. This converts the element into an electronic choke.

Transistor fully compensates for power surges, reduces its ripple. But it must be taken into account that this element still performs a semiconductor function, therefore, it is irrational to use it in devices operating at high frequencies.

Chokes are labeled in accordance with their parameters, so it is rather difficult to confuse the type of device.