Common mode chokes are used in EMI filtering circuits to help achieve electromagnetic compatibility (EMC). They do this by suppressing conducted noise, which is common in all types of power transmission and power lines.

The mounting direction has no impact on the operating characteristics of common mode chokes.

They do generate heat, it is in proportion to the power. The amount of power flowing is calculated using the standard I² x R equation, where R is the DC resistance of the common mode choke for a DC current, or the RMS value of an AC current. EMI chokes are designed to suppress high-frequency noise, and there is no significant loss introduced by this noise into the core or windings that might contribute to the heat generated.

Common mode refers to signals or noise flowing in the same direction in all lines. Differential (normal) mode refers to signals or noise flowing in opposite directions in a pair of lines.

To explain further, consider the configuration shown below, in which two copper wires are wound on a ferrite ring core. In this structure, two patterns can exist: one with currents flowing in the same direction (common mode), and another with currents flowing in opposite directions (differential mode).

Although it depends on the magnitude of the current and the time period during which the current is applied, our products are not covered under warranty when used with a current that is higher than the rated current at a specific ambient temperature.