FB pixel

Inductor Sizing Equation

Wheeler's formulas for inductance of air core coils which follow are useful for radio frequency inductors. The following formula for the inductance of a single layer air core solenoid coil is accurate to approximately 1% for 2r/l < 3. The thick coil formula is 1% accurate when the denominator terms are approximately equal. Wheeler's spiral formula is 1% accurate for c>0.2r. While this is a "round wire" formula, it may still be applicable to printed circuit spiral inductors at reduced accuracy.

The inductance in henries of a square printed circuit inductor is given by two formulas where p=q, and p≠q.

Wire Sizing for Inductors

The wire table provides "turns per inch" for enamel magnet wire for use with the inductance formulas for coils. The circular-mil cross-section area determines current carrying capacity of wires.

Lessons In Electric Circuits copyright (C) 2000-2020 Tony R. Kuphaldt, under the terms and conditions of the CC BY License.

See the Design Science License (Appendix 3) for details regarding copying and distribution.

Revised July 25, 2007

Use left and right arrow keys to change pagesUse left and right arrow keys to change pages.
Swipe left and right to change pages.\Swipe left and right to change pages.
Make Bread with our CircuitBread Toaster!

Get the latest tools and tutorials, fresh from the toaster.

What are you looking for?