Inductance is a type of characteristic of a closed loop, that is, when the amount of current passing through the closed loop changes, the inductance will generate electromotive force to resist the change of the amount of current. Such inductance is called self-inductance, which is a characteristic of the closed circuit itself.

The main parameters of inductors are inductance, permissible error, quality factor, distributed capacitance and rated current.

1.Nominal inductance

  The nominal inductance refers to the inductance marked on the inductor, which represents the inherent characteristics of the coil itself. It mainly depends on the number of coils, structure and winding method of the coil, and has nothing to do with the magnitude of the current. It reflects the ability of the inductance coil to store magnetic field energy, and also reflects the ability of the inductor to generate induced electromotive force when passing through a changing current. The unit is Henry (H).

2.Permissible error

  The maximum permissible deviation range of the actual inductance of the inductor relative to the nominal value is called the permissible error.

3.Distributed capacitance

  Distributed capacitance refers to the capacitance between the turns of the coil and between the coil and the core. The smaller the distributed capacitance of the inductor, the better its stability performance. Distributed capacitance can increase the equivalent energy dissipation resistance and the quality factor. To reduce distributed capacitance, silk-covered wires or multi-strand enameled wires are commonly used, and sometimes honeycomb winding methods are also used.

4.Rated current

  The rated current refers to the highest current value that the inductor is allowed to pass through during normal operation. If the operating current is higher than the rated current, the inductor will change its technical parameters due to heat generation, and even burn out due to over-current.

5.Quality factor

  Quality factor, also known as Q value or figure of merit, is the main parameter to measure the quality of inductors. It refers to the ratio of the inductive reactance presented by an inductor to its equivalent loss resistance when it operates at a certain frequency of AC voltage. The higher the Q value of the inductor, the lower its losses and the higher its efficiency.