Wire Length & Coil Frequency Calculator

The Formulas

1. Wire Length Formula:

\[Wire Length (m) = \pi \times Coil Diameter (mm) \times Number of Turns / 1000\]

2. Inductance Formula (Wheeler's formula for single-layer air-core coils):

\[L (\mu H) = \frac{d^2 \times n^2}{18d + 40l}\]

Where:

• L: Inductance in microhenries (µH)
• d: Coil diameter in inches
• n: Number of turns
• l: Coil length in inches

Calculation Steps

1. Calculate the wire length using the coil diameter and number of turns
2. Convert the coil and wire dimensions to inches for the inductance formula
3. Apply Wheeler's formula to calculate the approximate inductance

Example Calculation

Let's calculate for a coil with 25mm diameter, 10 turns, and 1mm wire diameter:

1. Wire Length:

\[Wire Length = \pi \times 25 \times 10 / 1000 = 0.785 \text{ meters}\]

2. Inductance:

\[L \approx \frac{(0.984^2 \times 10^2)}{(18 \times 0.984 + 40 \times 0.0394)} = 2.46 \mu H\]

Visual Representation

This visual shows a simplified representation of the coil based on our example calculation.