1. Choke coil refers to that some coils are wound on ferrite core or hollow, the number of turns is hundreds or dozens, and the self inductance coefficient is several milliohms.

      2. High frequency choke coil and low frequency choke coil are inductive coils.

      3. The inductance coil has the characteristics of restraining current changes, and the larger the inductance is, the more obvious this effect is.

      4. This effect hinders the current inductance. The size of the inductance and the working frequency of the inductance are related to the size of its own inductance.

      5. The low-frequency choke in the old Class A audio power amplifier is used to "connect DC and isolate AC".

      6. However, this ideal situation can not be satisfied, and can only be approximated to "pass DC and resist AC".

      7. As long as it meets the needs of the amplifier, a small loss of AC components is also allowed.

      8. The inductance of the choke is higher here.

      9. When the frequency is fixed (the audio frequency range is 20kHz - 20Hz), the inductance is required to be large.

      10. The extended data power filter choke is used to smooth the DC component after rectification and reduce its ripple voltage to meet the requirements of electronic equipment for DC power supply.

      11. The main technical indicators of power filter choke are: inductance, DC voltage drop.

      12. The inductance is determined by the required ripple coefficient when calculating the rectifier and filter; DC voltage drop affects rectifier output voltage and load regulation rate.

      13. The current of choke coil filtered by power supply includes DC and AC, and DC current is the main component.

      14. There are AC and DC magnetizing fields in the iron core of the choke, of which the DC component is the main part.

      15. According to the types of filters, power filter chokes can be divided into inductive input type and capacitive input type.

      16. Inductive input filter choke has high ripple voltage, and the AC magnetic induction intensity of iron core is generally above 0.1T; Capacitor input filter choke has low ripple voltage, and the AC magnetic induction of iron core is generally below 0.1T.

      17. The inductance of power filter choke coil decreases with the increase of DC magnetizing current, because the iron core becomes more and more saturated with the increase of DC magnetizing current.

      18. The introduction of non-magnetic gap in the magnetic circuit of the choke core can reduce the decrease of inductance with the increase of DC magnetizing current. Corresponding to the given DC magnetizing current, there is an optimal non-magnetic gap. Corresponding to this optimal gap, the power filter choke can obtain the maximum inductance value.