Inductance Conversion
Picohenry to henry conversion
Required Parameters
Waiting for input data...
Quick Answer
1 H = 1000 mH = 1,000,000 µH = 10⁹ nH. Each prefix step is ×1000. RF inductors use nH, switching regulator inductors use µH, power inductors use mH, and transformer primaries use H.
Inductance Conversion Calculator
Convert between inductance units: Henrys, millihenrys, microhenrys, and nanohenrys.
Conversion
- 1 H = 1,000 mH = 1,000,000 uH = 1e9 nH
Design Notes
Inductance selection for switching regulators: L = (Vin-Vout) × Vout / (Vin × fsw × ΔIL). Higher inductance reduces ripple but slows transient response. Always check saturation current and SRF in the datasheet.
Common Mistakes
- 1
Forgetting that every conductor has parasitic inductance (8-10 nH per cm of PCB trace).
- 2
Using an inductor above its self-resonant frequency (SRF) where it behaves as a capacitor.
- 3
Ignoring DC bias effects — inductance drops significantly as current approaches the saturation rating.
Knowledge Base
How many uH in a mH?
1,000 microhenries (µH) = 1 millihenry (mH). The full scale: 1 H = 1,000 mH = 1,000,000 µH = 1,000,000,000 nH. Each prefix step is a factor of 1,000.
What inductance units are used in electronics?
nH (nanohenry): RF inductors, PCB traces, bond wires. µH (microhenry): switching regulator inductors, sensor coils. mH (millihenry): audio crossover inductors, relay coils, common-mode chokes. H (henry): large power inductors, transformer primaries. Most electronic inductors are in the 1 nH to 100 mH range.
What is a typical inductor value for a buck converter?
For a buck converter: L = (Vin - Vout) × Vout / (Vin × fsw × ΔIL). Typical values: 1-2.2 µH for high-frequency converters (1-3 MHz), 4.7-22 µH for medium-frequency (100-500 kHz), 100-470 µH for low-frequency (50-100 kHz). Higher inductance = lower ripple but slower transient response.
What does inductance depend on?
L = µ₀ × µr × N² × A / l, where µ₀ = permeability of free space, µr = relative permeability of the core, N = number of turns, A = core cross-section area, l = magnetic path length. More turns, larger core, and higher permeability all increase inductance.
What is parasitic inductance?
Every conductor has inductance, typically measured in nH. A 1 cm PCB trace has roughly 8-10 nH. A through-hole resistor lead has 5-8 nH. A via has 0.5-1.5 nH. At high frequencies, these parasitic inductances become significant and can cause ringing, overshoot, and EMI problems.
What is mutual inductance?
When two inductors are magnetically coupled, changing current in one induces voltage in the other. Mutual inductance M is measured in the same units (H, mH, µH). The coupling coefficient k = M / √(L1 × L2), ranging from 0 (no coupling) to 1 (perfect coupling). Transformers have k ≈ 0.95-0.99.
How do I measure inductance?
Use an LCR meter, which applies an AC signal and measures the impedance to calculate L. Inductance varies with frequency (due to core losses and parasitics), DC bias current (core saturation), and temperature. Always measure at the operating frequency and current for accurate results.
What is inductor saturation?
When the magnetic core reaches its maximum flux density, inductance drops dramatically (by 50-90%). This causes inductor current to spike, potentially damaging the circuit. Saturation current is specified in datasheets. Ferrite cores saturate sharply; powdered iron cores saturate gradually (soft saturation).
What is the Q factor of an inductor?
Q = XL / R_DC = 2πfL / R_DC. Higher Q means lower losses. RF inductors aim for Q above 30-50. Power inductors typically have low Q (1-10) because they prioritize current handling over signal purity. Q varies with frequency and peaks at a specific frequency for each inductor.
What is the self-resonant frequency of an inductor?
Every inductor has parasitic capacitance between its windings. The SRF is where the inductance resonates with this capacitance: SRF = 1/(2π√(LC_parasitic)). Above the SRF, the inductor behaves as a capacitor. Always use inductors well below their SRF (typically at less than 1/3 of SRF).
Related Engineering Tools
Reactance Calculator
Inductive and capacitive reactance
Low Pass / High Pass Filter Calculator
-3 dB cutoff for RC and RL filters
Capacitance Conversion
Unit conversion and basic capacitor code decoding
Frequency to Wavelength Conversion
Convert frequency and wavelength with velocity factor