1. The inductive reactance XL
XL inductance inductance element in the parameter list general finding, but it is closely related with the inductance and quality factor classification inductance element Q and other parameters in the analysis of the circuit is also often need to use, it is dedicated to give a brief introduction here. Mentioned before, due to the self-inductance of the inductor is always the potential to prevent the coil current changes, so there is resistance coil alternating current role of resistance to use inductive reactance XL to represent. XL with the coil inductance L and the AC frequency f proportional calculated as: XL (Ω) = 2лf (Hz) L (H). Not difficult to see, XL small low-frequency current through the coil. XL through the direct current is zero, the DC resistance of the coil only play the role of resistance, because resistance: - generally small, so the approximate short circuit. XL high-frequency current through the large, if L is large, the approximate open. Such characteristics of the coil opposite the capacitors, so the use of an inductor and a capacitor element can be composed of a variety of high, medium and low pass filter, and a tuning circuit, frequency selection circuit and choke coil circuit and so on.
2. Inductance L
Inductance L also called self inductance, self inductance element is a physical quantity sensing capability. When occurs through a coil of flux (ie the number of magnetic field lines through a area) changes, the coil will produce electrical potential, which is the phenomenon of electromagnetic induction. The potential generated by said induction potential, the potential is proportional to the flux variation of speed and turns. When the current through the coil changes, but also changes in the magnetic flux generated by the coil, the magnetic flux passing the coil, the coil ends will produce EMF, which is self-induced phenomenon. Inductance potential always stop the current changes direction, like a coil inertia, inertia on the size of such electromagnetic inductance amount L to represent. L size and the number of turns, size and magnetic materials are concerned, the use of silicon as a coil or ferrite core, a smaller number of turns can obtain a large inductance. The basic unit of L is H (Henry), the actual used more units of mH (mH) and IxH (micro Henry), in terms of their relations as follows: 1H = 103mH = 106 μH.
3. DC resistance
That is the DC resistance of the inductor itself, available multimeter or ohmmeter measured directly.
The quality factor Q
This was stated inductor quality parameters, also known as Q value or merit. When the coil is working at a certain frequency AC voltage, the inductive reactance XL equivalent loss resistance and the Q value is the ratio, expressed as follows: Q = 2лL / R. Thus, the coil inductance greater the loss resistance is smaller, the higher its Q value. It is worth noting that the loss resistance may be regarded as substantially in the coil DC resistance mainly at lower frequencies f; when higher f, due to dielectric loss bobbin and impregnation of the core and the shield loss, high wire frequency skin effect losses and other effects obvious, R should include various losses, including the equivalent loss resistance, can not count only the DC resistance.
Q values mostly in the tens to hundreds. The higher the Q value, loss of the circuit, the higher the efficiency, but the Q value increased to a certain extent would be subject to various constraints, and many circuit coil Q value is no high demands, so the specific Q value should be decided depending on the circuit requirements.
5. Rated current
Generally it refers to allow long DC current through the inductor element value. In the selection of the inductive element, if the current flowing through the circuit is greater than the rated current value, on the need to use other models of the inductor current rating to meet the requirements.
Identification inductance element is very easy. Fixed inductors are generally the inductance and models directly marked on its surface, a look that is known. Some of the inductor model or inductance marked only one of some inductance element marked only models and trademarks, such as the Notes other parameters, only refer to the product manual or relevant information.