Inductor Self Resonant Frequency SRF

Inductor self resonant frequency SRF

We measured Series Resonant Frequency “SRF” of some axial, SMD and hand wind inductors.

The self resonant frequency of an inductor is the frequency at which the parasitic capacitance of the inductor resonates with the ideal inductance of the inductor resulting in an extremely high impedance. At this frequency the device looks like an open circuit.

The parasitics of an inductor vary based on the type of inductor – wire wound inductor, multi-layer inductor, conductive film inductor etc.

Testing.

Axial inductors like this one:

Axial inductor

Axial inductor 560nH Series Resonant Frequency SRF

Axial inductor 560nH Series Resonant Frequency SRF

Axial inductor 1uH SRF

Axial inductor 1uH SRF

Axial inductor 10uH Series Resonant Frequency

Axial inductor 10uH Series Resonant Frequency

Axial inductor 22uH SRF

Axial inductor 22uH SRF

Axial inductor 100uH Series Resonant Frequency SRF

Axial inductor 100uH Series Resonant Frequency SRF

Axial inductor 1000uH SRF

Axial inductor 1000uH SRF

Axial inductor Iskra amp measured inductance 5.9uH 

Axial inductor Iskra amp measured induktance 5.9uH

Axial inductor Iskra amp 5.9uH S21

Axial inductor Iskra amp 5.9uH SRF

BCN-560N SMD Chip inductor 560nH SRF from rf-microwave

BCN-560N Chip inductor 560nH SRF from rf-microwave

BCN-10U SMD Chip inductor 10µH SRF from rf-microwave

BCN-10U Chip inductor 10uH SRF

Hand wind inductor (ver2) measured inductance 2.7µH

Hand wind inductor 2.7uH

Hand wind inductor 2.7uH (ver2) S21

Hand wind inductor 2.7uH ver2 Series Resonant Frequency SRF

Hand wind inductor (ver3) measured inductance 11.3 µH

Hand wind inductor 11uH

Hand wind inductor 11.3uH (ver3) S21

Hand wind inductor 11uH ver3 SRF

Hand wind inductor (ver24) measured inductance 45 µH

Hand wind inductor 45uH

Hand wind inductor 45 uH (ver24) S21

Hand wind inductor 45uH ver24

 

Capacitor self resonant frequency SRF popular for amateur use. We used 0805 and 1206 SMD capacitors, film capacitors and electrolytic capacitors with wire + VIA length about 2 to 4mm. You can learn more about it in the link here.

All measurements were conduced on HP8753ES. This presentation is for amateur use only.

73 Goran YU1CF