What Is A Choke, How Does IT Work And What Is IT Used For

High-frequency chokes refer to coils that are wound around the ferrite core, some are hollow, the number of turns is hundreds or dozens, and the self-inductance coefficient is several millihen. High frequency choke coil This choke coil only has a greater blocking effect on high frequency alternating current, the blocking effect on low frequency alternating current is very small, and the blocking effect on DC is even smaller, so it can be used to "pass DC, block AC, pass low frequency, block high frequency".

The Working Principle OF The Choke

The working principle of the choke is based on the phenomenon of inductance, that is, by bending a wire or winding an iron core, the voltage is converted into a magnetic field. When a resistive load causes a change in current in the circuit, the magnetic field changes accordingly. This changing magnetic field will produce a reverse electromotive force, which will generate an electromotive force in the choke, offset the change in magnetic flux generated by the original current, and achieve the blocking of the high-frequency component.

Choke Characteristics

High frequency chokes and low frequency chokes are inductors. The inductor coil has the characteristic of suppressing current change, and the larger the inductance, the more obvious this effect is. This effect on the obstruction of the current is induced, and the size of the inductive reactance and the operating frequency of the inductor are related to the size of its own inductance. In the old class A audio power amplifier, the low-frequency choke, its role is to "pass DC, separate AC". However, this ideal situation is not satisfied, and can only be approximated to "pass DC, block AC". As long as it meets the needs of the amplifier, a small loss of the AC component is also allowed. The reactor is more reactive here. When the frequency is certain (audio range is 20kHz-20Hz), the inductance is required to be relatively large. Usually on the order of millihen. The high-frequency choke generally works in the high-frequency current, and its role is mostly frequency selection, which requires that its inductance is not very large, generally on the order of micro Heng. In fact, the statement of "DC, AC" and "low frequency and high frequency" is for the application. But the purpose is to adjust the inductance of the inductor to meet our needs.

How The Choke Works

A high frequency choke is actually a coil. When the coil current changes, the magnetic flux in the coil also changes, which causes the coil to generate an induced electromotive force to block the current change. The faster the current changes, the larger the induced electromotive force, and the more obvious the hindering effect.

When the high-frequency choke works, the high-frequency current is hindered by the action of the coil, but for the low-frequency current, the hindered effect is also small because of the induced potential generated by it. For direct current, there is basically no blocking effect, so the blocking effect of the high-frequency choke is selective

The Role OF The Choke Coil

Chokes can play an important role in electronic circuits, such as:

Prevent the interference of high-frequency noise and strengthen the transmission of low-frequency signals.

Protect electronic components from high-frequency components.

Provide power isolation and noise reduction functions to make the performance of electronic equipment more stable and reliable

Types OF Chokes

According to different uses, chokes can be divided into various types, such as high-pass, low-pass and band-pass.

High-pass choke: allows high-frequency signals to pass through and filters out low-frequency signals.

Low-pass choke: allows low-frequency signals to pass through and filters out high-frequency signals.

Bandpass choke: Only signals within a specific frequency range are allowed to pass through.