1, inductance L and the accuracy
Has nothing to do with the current size. In addition to the inductance coilspecial (color coded inductors), inductance coil L said the inherent characteristics. Inductance is generally not specifically labeling on the coil, anda specific name label. The size of coil inductance, mainly depends on the diameter of the coil, turns and has no iron core etc.. Use different inductance coil, inductance required are also different. For example, the high frequency circuit, inductance coil for general 0.1uH100Ho
Error of actual inductance and inductance between the requirements ofprecision, inductance. Depending on the application requirements on it. The higher demands on the oscillation coil, o.2-o.5% on the coupling coil and the high-frequency choke requirements are low, allowing 1015% for certain requirements inductance precision is very high places, the general can onlytest instrument in the winding, realized by adjusting the position of the magnetic core near the edges of the coil of wire or coil in the distance.
2, inductance XL
Hinder the inductance coil of AC current size called inductance XL ohms. And the inductance quantity of L and the frequency of the alternating current f in relation to XL=2 PI fL
3, the quality factor Q
The quality factor of the coil
High frequency coil is usually 50300 of a tuning circuit coil Q value higher, the quality factor Q is used to indicate the size of the coil loss. The resonant circuit coil with high Q value and the capacitance is composed of a resonant characteristics better; resonant circuit composed of coils and capacitors with low Q, the resonance characteristics is not obvious. The coupling coil, the requirements to be low, the high frequency choke and low-frequency choke,no requirement. Q value of the size effect of loop, selectivity, efficiency, andstability of the frequency filtering characteristics. Generally want the Q value,but increased the Q value of the coil is not easy, therefore, should be based on the actual use of places, on the coil Q value of appropriate requirements.
The quality factor of the coil was:
Q=. L/R in the:
The angular frequency omega work;
The inductance of L coil;
By DC resistance, high frequency resistance (caused by the skin effect and proximity effect loss) media etc.. Total loss total loss resistance coil resistanceof R coil.
In order to reduce the high frequency resistance; insulated line with multi strand instead of having the same president the single strands, in order to improve the quality factor of the Q coil can use silver plated copper wire. In order to reduce the skin effect; using high-frequency ceramic dielectric loss is small for the skeleton, to reduce the dielectric loss. Using core although increased core loss, but can greatly reduce the number of turns of the coil,thereby reducing the conductor DC resistance, favorable for improving the coilQ value.
The ratio of Q to XL and its equivalent resistance inductance, quality factor Qrepresents a physical volume coil quality. Namely: Q=XL/R coil Q value is high,the smaller the loop loss. The Q value of the coil and DC resistance ofconductor, dielectric loss skeleton, shield or core loss caused by factors, high frequency skin effect and other relevant. Coil Q value is typically tens to hundreds of. Using the core coil, a plurality of strands of rough coil can improve the Q value of the coil.
4, the distributed capacitance
The poor stability, and shield coil turns and turns of the coil, coil and platecover, between the capacitor is called the distributed capacitance. The distributed capacitance of the existence of coil Q value decreases. So thedistributed capacitance of the coil smaller is better. Using piecewise windingcan reduce the distributed capacitance.
5, the inherent capacitance
Between the multilayer winding layer and layer, the existence of the distributed capacitance between the turns and turns of the coil winding. There are alsodistributed capacitance. The distributed capacitance can be equivalent to a capacitance is connected in parallel with the coil.
6, permissible error:
The actual value and the nominal inductance percentage difference divided by the nominal value of the.
The letter ABCDE is commonly used for respectively, 7 of nominal current: refers to the size of the current through the coil to allow. The nominal currentvalue is 50mA 150mA 300mA 700mA 1600mA.
