Frequently asked questions In what does this inductance calculator differ from the rest? Dr. James F.

Self-resonant frequency λ/4 parallel self-resonant frequency of n = 0 sheath helix mode 7, 8Ĭopy & paste Achieving a high quality factorĬoils achieving the highest quality factor require large diameter wire, strip or tubing and usually exhibit a cubical form factor i.e. the coil length equals the coil diameter. Parallel stray capacitance at the design frequency, from Corum’s sheath helix waveguide formula 7

Series AC resistance of the round wire coil at the design frequency Lumped equivalent circuit lumped equivalent circuitįrequency-independent series inductance from the current-sheet coil geometrical formula, corrected for field non-uniformity and round wire 1, 3– 6 Results Effective equivalent circuit effective equivalent circuitĮffective series inductance at the design frequency from Corum’s sheath helix waveguide formula, corrected for field non-uniformity and round wire 1, 3, 6, 7Įffective series reactance of the round wire coil at the design frequencyĮffective series AC resistance of the round wire coil at the design frequency 9Įffective unloaded quality factor of the round wire coil at the design frequency Sheath helix waveguide mode effective pitch angleĪxial propagation factor of n = 0 sheath helix waveguide mode at the design frequency 7, 8Ĭharacteristic impedance of n = 0 sheath helix waveguide mode at the design frequency 7 Wire or tube conductor physical wire length Proximity factor interpolated from empirical Medhurst data 1, 2Įffective coil diameter according to Stroobandt (see below)Ĭorrection factors correction factor for field non-uniformity according to Lundin 1, 3Ĭorrection factor for the self-inductance of the round conductor according to Knight and Rosa 1, 4, 5Ĭorrection factor for the mutual-inductance between round conductor windings according to Knight 1, 6 Length of the coil, measured from the connecting wires centre to centre Mean diameter of the air core coil, measured from conductor centre to conductor centre (include the wire insulation thickness, if any) Input Input round wire coil with dimensions and current-sheet approximation 1 Stroobandt, ON4AA Copyright 2007–2020, licensed under Creative Commons BY-NC-SA RF Inductance Calculator for Single‑Layer Helical Round‑Wire Coils Serge Y.

Audio air core inductor calculator