Use this easy to use coil inductance calculator specially designed to determine the inductance of a coil based on its physical characteristics using L = (d^2 * N^2) / (18d + 40l) formula.
Consider a solenoid with 100 turns, a length of 10 cm, and a diameter of 2 cm. By inputting these parameters into a coil inductance calculator, you can swiftly obtain the inductance value without manual computations.
This streamlines the design process for various applications, such as:
- Audio equipment: Optimizing speaker crossovers
- Power supplies: Designing efficient transformers
- RF circuits: Tuning antenna matching networks
Coil Inductance Calculator
| Diameter (mm) | Length (mm) | Turns | Calculated Inductance (μH) |
|---|---|---|---|
| 5 | 10 | 20 | 1.56 |
| 10 | 20 | 50 | 12.34 |
| 15 | 25 | 75 | 41.67 |
| 20 | 30 | 100 | 104.18 |
| 25 | 35 | 125 | 217.53 |
| 30 | 40 | 150 | 397.91 |
| 35 | 45 | 175 | 650.00 |
| 40 | 50 | 200 | 950.34 |
| 45 | 55 | 225 | 1300.00 |
| 50 | 60 | 250 | 1620.45 |
| 55 | 65 | 275 | 2000.00 |
| 60 | 70 | 300 | 2430.00 |
Coil Inductance Formula
For a single-layer air-core solenoid, the Wheeler formula is widely used:
L = (d^2 * N^2) / (18d + 40l)Where:
- L = Inductance in microhenries (μH)
- d = Coil diameter in inches
- N = Number of turns
- l = Coil length in inches
Let’s calculate the inductance of a coil with the following parameters:
- Diameter (d) = 1 inch
- Number of turns (N) = 50
- Length (l) = 2 inches
L = (1^2 * 50^2) / (18 * 1 + 40 * 2)
L = 2500 / 98
L ≈ 25.51 μHHow to Calculate the Inductance of a Coil?
Calculating coil inductance involves several steps:
- Measure physical parameters: Determine the coil’s diameter, length, and number of turns.
- Choose appropriate formula: Select the formula that best fits your coil’s geometry.
- Convert units: Ensure all measurements are in the correct units for the chosen formula.
- Perform calculation: Substitute values into the formula and compute the result.
- Verify result: Cross-check the calculated value with a coil inductance calculator or physical measurement.
Let’s walk through an example using a multilayer air-core coil:
Given:
- Inner diameter (Di) = 15 mm
- Outer diameter (Do) = 25 mm
- Length (l) = 30 mm
- Number of turns (N) = 200
We’ll use the Wheeler’s multilayer coil formula:
L = (0.31 * (Do + Di)^2 * N^2) / (6 * (Do - Di) + 9 * l + 10 * (Do - Di))Converting to centimeters: Di = 1.5 cm, Do = 2.5 cm, l = 3 cm
L = (0.31 * (2.5 + 1.5)^2 * 200^2) / (6 * (2.5 - 1.5) + 9 * 3 + 10 * (2.5 - 1.5))
L = 496000 / 39
L ≈ 12717.95 μH or 12.72 mH
What is Coil Inductance?
Coil inductance is a fundamental property of an inductor that quantifies its ability to store energy in a magnetic field when an electric current flows through it. It’s measured in henries (H) and denoted by the symbol L.
Key aspects of coil inductance include:
- Proportionality: Inductance is directly proportional to the number of turns squared (N²).
- Geometry dependence: The coil’s shape and dimensions significantly influence its inductance.
- Material effects: Core materials can drastically alter a coil’s inductance.
- Frequency sensitivity: At high frequencies, parasitic capacitance can affect the apparent inductance.
References
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