Calculation
1/Ltotal = 1/L1 + 1/L2 (+ 1/L3)
With no magnetic coupling, reciprocals of inductance add for parallel-connected coils, as with resistors.
Busch 2006, Abschnitt 2.6.1, Gl. (2.53)
Inductors in parallel (uncoupled)
With no magnetic coupling, reciprocals of inductance add for parallel-connected coils, as with resistors.
MINTSI
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Result
Select a target and calculate.
Understand the inputs
- Inductance L1 — First inductor in the parallel combination.
- Inductance L2 — Second inductor in the parallel combination.
- Inductance L3 (optional) — Third inductor; set to 0 if only two inductors are present.
- Total inductance Ltotal — Inductance of the complete parallel combination; always smaller than the smallest individual inductance.
Example
10 mH and 22 mH in parallel give 6.875 mH.
Assumptions and limits
No magnetic coupling and ideal, resistance-free coils; real leakage inductance and coupling are not included.
Understand Inductors in parallel (uncoupled)
This calculator determines the total inductance of two or three magnetically uncoupled inductors connected in parallel.
What does this quantity describe?
With no magnetic coupling, reciprocals of inductance add for parallel-connected coils: 1/Ltotal=1/L1+1/L2(+1/L3), analogous to resistors in parallel.
Formula and variables
1/Ltotal = 1/L1 + 1/L2 (+ 1/L3)
1/Ltotal = 1/L1 + 1/L2 (+ 1/L3)
| Symbol / input | Meaning |
|---|---|
| Inductance L1 | First inductor in the parallel combination. |
| Inductance L2 | Second inductor in the parallel combination. |
| Inductance L3 (optional) | Third inductor; set to 0 if only two inductors are present. |
| Total inductance Ltotal | Inductance of the complete parallel combination; always smaller than the smallest individual inductance. |
Choose the inputs correctly
L1, L2 and optionally L3 are the inductances of the parallel-connected, uncoupled coils.
How to use the calculator
Take inductance values from a datasheet or measurement; keep coils sufficiently spaced to avoid coupling.
Worked example
10 mH and 22 mH in parallel give Ltotal=6.875 mH.
Understand the result and units
Ltotal is always smaller than the smallest individual inductance.
All inductances are entered in the same or convertible units (H, mH, µH).
Typical applications
Reducing an available inductance by paralleling existing coils.
Assumptions, limits and common mistakes
No magnetic coupling and ideal, resistance-free coils; real leakage inductance is not included.
Common mistake: Do not use the series (direct-sum) formula for the parallel case.
Frequently asked questions
What is “Inductors in parallel (uncoupled)” used for?
Reducing an available inductance by paralleling existing coils.
Where do the input values come from?
L1, L2 and optionally L3 are the inductances of the parallel-connected, uncoupled coils.
What does the result not cover?
No magnetic coupling and ideal, resistance-free coils; real leakage inductance is not included.