All inductors have capacitance between their windings, which is called distributed capacitance.

As the frequency increases, the inductor's inductive reactance (XL) and AC resistance (R) will increase at the same time. When the frequency is higher than the limit that the inductance can withstand, the inductive reactance of the inductor will decrease sharply until it disappears, and it is characterized by the capacitive load. The frequency point (XL = 0) at which this phenomenon occurs in the inductor is called the self-resonance frequency point of the inductor, that is, before this frequency, the inductance is inductive, L > 0, and after this frequency, it is capacitive, L < 0.

When designing electronic circuits, especially high-frequency circuits, engineers have to consider about the normal working frequency of the circuit and to propose that the SRF must be greater than a certain limit value to ensure the normal operation of the circuit.

The factors affecting the SRF value of inductor include magnetic-core material, wire diameter, and the number of turns (L value). Because the general application frequency of high-current inductors is under 1 MHz, this frequency range is far from reaching the self-resonant frequency point, so there is no SRF in the specification.