Q.
What is the difference between common mode impedance, differential mode impedance and characteristic impedance?
- EMC Components >
- Signal Line Common Mode Chokes/Filters
A.
Common mode impedance: refers to a characteristic in response to common mode signals (noise).
Differential mode impedance: refers to a characteristic in response to leakage inductance.
Characteristic impedance: refers to the line impedance when two lines of a common mode filter / choke are considered as a differential transmission line. It has no correlation with the common mode impedance.
It is determined by the balance between the leakage impedance and the line capacity.
