Inductor
A passive component that stores energy in a magnetic field and opposes changes in current. Used in filters, switching power supplies, chokes, and resonant circuits.
Properties
| Property | Description | Default | Range |
|---|---|---|---|
| Inductance | Magnetic energy storage capacity (H) | 100 µH | 1 nH – 10 H |
| DCR | DC resistance of the winding wire (Ω) | 0.1 Ω | 0.001 Ω – 100 Ω |
| Saturation current | Current at which the core saturates and inductance collapses (A) | 2 A | 0.01 A – 500 A |
Simulation behavior
At DC steady state the inductor acts as a resistor equal to DCR. During transients it resists current changes — current through an inductor cannot change instantaneously. The time constant in an RL circuit is τ = L / R.
When current reaches the saturation current, the effective inductance drops sharply toward zero. The inductor then behaves as a pure resistance (DCR), allowing current to rise rapidly. Sustained operation above saturation causes thermal failure.
Tips
- Back-EMF: when current through an inductor is interrupted suddenly (e.g., a switch opens), it generates a large voltage spike. Always provide a freewheeling path (a diode or snubber) to clamp this spike.
- In a boost or buck converter, lower DCR increases efficiency — real-world power inductors are specified with DCR values as low as a few milliohms.
- Combine an inductor with a capacitor to form an LC tank circuit. The resonant frequency is f = 1 / (2π√(LC)).