Technical Tools & References

Rod Permeability Calculator

A few things to keep in mind when using this tool: The length to diameter ratio of the core can significantly impact the ability to differentiate between materials. Cores with a low length to diameter ratio have a very low effective permeability (µrod) that is nearly indistinguishable between material grades. A trick to evaluate a rod type core that has a low length to diameter ratio is to take several of them placed end to end and test them as one longer rod. The air gaps between the cores will have a relatively insignificant impact on the effective permeability given that the majority of the magnetic field is not contained within the core. Coverage of a coil over a rod is an important factor as well. Getting a complete coverage of the rod will yield a lower inductance modifier (K) and therefor a higher inductance making distinguishing between different materials easier

Rod Diameter in mm”
Rod Length in mm
Number of turns
Coil Length in mm
Series Inductance in microhenries
Ae in cm2
Length to Diameter ratio
Inductance Modifier (K)
Rod Permeability