Solenoid Inductance Calculator

Calculate the self-inductance of solenoid coils using physical parameters

Calculate Solenoid Inductance

Total number of wire turns in the coil

Radius of the circular cross-section

Length of the solenoid coil

Solenoid Inductance Results

0
Nanohenries (nH)
Solenoid Inductance
0 cm²
Cross-sectional Area
In Henries:0 H
In Millihenries:0 mH
In Microhenries:0 μH
Turns per meter:0 turns/m

Formula: L = μ₀ × N² × A / l

Calculation: L = 1.257e-6 × 0² × 0 / 0

Energy stored (at 1A): 0 J

Time constant (with 1Ω): 0 s

Solenoid Analysis

Example Calculation

Audio Inductor Design

Application: Audio crossover network inductor

Number of turns: 150 turns

Coil diameter: 8 cm (radius = 4 cm)

Coil length: 15 cm

Calculation

Cross-sectional area: A = π × (0.04 m)² = 5.027 × 10⁻³ m²

L = 1.257 × 10⁻⁶ × 150² × 5.027 × 10⁻³ / 0.15

L = 1.257 × 10⁻⁶ × 22,500 × 5.027 × 10⁻³ / 0.15

L ≈ 947 μH

Suitable for mid-frequency crossover applications

Solenoid Inductance Formula

L = μ₀ × N² × A / l

Solenoid inductance formula

L: Inductance (H)
μ₀: Vacuum permeability (1.257 × 10⁻⁶ H/m)
N: Number of turns
A: Cross-sectional area (m²)
l: Solenoid length (m)

Typical Inductance Values

RF chokes:1-100 μH
Audio inductors:100 μH - 10 mH
Power inductors:1-100 mH
Filter chokes:1-20 H
Transformers:10 mH - 100 H

Design Considerations

Turn Density

Higher turn density increases inductance

Core Material

Ferrite cores multiply inductance by μᵣ

Length/Diameter Ratio

Long solenoids (l/d > 10) for accuracy

Wire Resistance

Consider DC resistance and skin effect

Solenoid Tips

Inductance is proportional to N² (turns squared)

Larger cross-sectional area increases inductance

Shorter length increases inductance

Add ferrite core to multiply inductance by μᵣ

Consider parasitic capacitance at high frequencies

Understanding Solenoid Inductance

What is a Solenoid?

A solenoid is a tightly wound helical coil of wire that creates a magnetic field when current flows through it. It acts as an inductor in electrical circuits, storing energy in its magnetic field and resisting changes in current.

Key Physical Principles

  • Self-inductance from magnetic flux linkage
  • Energy storage in magnetic field
  • Lenz's law opposition to current changes
  • Electromagnetic induction effects

Inductance Formula Derivation

L = μ₀ × N² × A / l

For air-core solenoids

Energy and Time Relations

Energy stored: E = ½LI²
Voltage relation: V = -L(dI/dt)
Time constant: τ = L/R
Reactance: XL = 2πfL

Note: This formula assumes an air-core solenoid. With ferrite cores, multiply by relative permeability μᵣ which can range from 10 to 10,000.

Applications & Use Cases

Power Electronics

Buck/boost converters, energy storage, power factor correction

RF Circuits

Antenna tuning, impedance matching, filter networks

Audio Systems

Crossover networks, speaker drivers, equalization filters

Design Guidelines

Maximizing Inductance

  • • Increase number of turns (quadratic effect)
  • • Use larger cross-sectional area
  • • Reduce solenoid length
  • • Add high-permeability core material
  • • Minimize air gaps in magnetic circuit

Practical Considerations

  • • Wire gauge affects resistance and current capacity
  • • Core saturation limits maximum current
  • • Parasitic capacitance affects high-frequency response
  • • Thermal management for power applications
  • • Mechanical stability and vibration resistance