Common-Mode Choke Impedance
Estimate one winding's series RL impedance magnitude at frequency f as √[R²+(2πfL)²]. Enter the effective common-mode inductance and resistance at the operating point; real choke impedance also includes core loss, capacitance, and self-resonance.
Description
Estimate one winding's series RL impedance magnitude at frequency f as √[R²+(2πfL)²]. Enter the effective common-mode inductance and resistance at the operating point; real choke impedance also includes core loss, capacitance, and self-resonance.
Common-Mode Choke Impedance: Estimate one winding's series RL impedance magnitude at frequency f as √[R²+(2πfL)²]. Enter the effective common-mode inductance and resistance at the operating point; real choke impedance also includes core loss, capacitance, and self-resonance.
When to use Common-Mode Choke Impedance
Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.
- Frequency (Hz)
- Required number input.
- Common-mode inductance (H)
- Required number input.
- Series resistance (Ω)
- Required number input.
How Common-Mode Choke Impedance works
Estimate one winding's series RL impedance magnitude at frequency f as √[R²+(2πfL)²]. Enter the effective common-mode inductance and resistance at the operating point; real choke impedance also includes core loss, capacitance, and self-resonance. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.1
- Impedance Magnitude ohm
- The resulting impedance magnitude ohm returned as a number.
Limitations and assumptions
- EMI attenuation and protection calculations depend on source and load impedance, parasitics, layout, enclosure seams, cable coupling, frequency, pulse shape, and test standard. Component impedance curves alone do not demonstrate emissions, immunity, or ESD compliance.
- Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.
Alternative or Complementary approaches
Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.
References
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Electromagnetic interference — Wikipedia contributors
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