Common-Mode Choke

Common Mode Chokes are used when many electrical devices may be connected to the same power lines (or power supply lines) and therefore substantial electrical noise can exist on these lines.Line filters prevent excessive noise from being conducted between electronic equipment and the AC line. Noise is typically common to both lines and in the same direction. Common mode chokes are designed so that common mode current creates a magnetic flux (through mutual inductance) that adds to attenuate the CM noise signal.