Flat Spiral Coil Inductor Calculator

Inductance Formula:

\[ L = \frac{r_{avg}^2 \times N^2}{2.54 \times (r_{outer} + 0.25 r_{inner})} \]

Average Radius (r_avg):

Number of Turns (N):

Outer Radius (r_outer):

Inner Radius (r_inner):

Inductance (L): μH

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1. What is a Flat Spiral Coil Inductor Calculator?

Definition: This calculator estimates the inductance of a flat spiral coil based on its physical dimensions and number of turns.

Purpose: It helps electronics engineers and hobbyists design flat spiral inductors for circuits, RF applications, and wireless power systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ L = \frac{r_{avg}^2 \times N^2}{2.54 \times (r_{outer} + 0.25 r_{inner})} \]

Where:

\( L \) — Inductance (microhenries, μH)
\( r_{avg} \) — Average radius of the coil (cm)
\( N \) — Number of turns
\( r_{outer} \) — Outer radius of the coil (cm)
\( r_{inner} \) — Inner radius of the coil (cm)

Explanation: The formula approximates the inductance of a flat spiral coil based on its geometric properties.

3. Importance of Inductance Calculation

Details: Accurate inductance calculation is crucial for designing filters, oscillators, impedance matching networks, and wireless charging systems.

4. Using the Calculator

Tips: Enter all dimensions in centimeters. The average radius is typically (r_outer + r_inner)/2. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the accuracy of this formula?
A: This is an approximate formula accurate to within about 5% for typical spiral coils.

Q2: How do I measure the radii?
A: Measure from the center to the inner/outer edges of the coil. Average radius is (r_outer + r_inner)/2.

Q3: What wire gauge should I use?
A: Wire gauge affects resistance but not inductance in this approximation. Choose based on current requirements.

Q4: Can I use this for rectangular spirals?
A: This formula works best for circular spirals. Rectangular spirals require different calculations.

Q5: How does spacing between turns affect the result?
A: This formula assumes typical spacing. For very tight or loose winding, results may vary.