Why do series inductors add like resistors?

In series circuits, the same current flows through all components, and inductors oppose current change (not current itself). Each inductor's opposition adds up, creating a higher total opposition to current changes.

What's the difference between series and parallel inductors?

Series inductors add directly (L_eq = L₁ + L₂ + ...), while parallel inductors use reciprocal formula (1/L_eq = 1/L₁ + 1/L₂ + ...). Series yields larger inductance; parallel yields smaller.

Does the order of series inductors matter?

No, the order does not matter in ideal series inductors with no mutual coupling. The total equivalent inductance remains the same regardless of arrangement.

What's mutual inductance and why should I avoid it?

Mutual inductance occurs when inductors are close together and their magnetic fields interact, violating the assumption that L_eq = L₁ + L₂. Physically separate inductors on a PCB to minimize this effect.

When should I use series inductors?

Series inductors are used in applications needing high inductance values (when individual components don't exist), increasing filtering, or improving input impedance in power supplies.

How do parasitic resistances affect series inductors?

Real inductors have resistance (ESR). In series, total resistance = R₁ + R₂ + Rₙ. At low frequencies, parasitic resistance may dominate circuit behavior, not inductance.

Can I calculate series inductance with DC?

Yes, inductors don't restrict DC current flow (ideal inductors have zero resistance). DC only sees the resistance of the wire; inductance effects only appear during current transients or AC.

What happens if one inductor in series opens?

If one inductor opens (breaks), the entire series circuit is broken, and no current flows. This is different from parallel, where other inductors continue to conduct.