What's the purpose of each part of circuit circled in the picture bellow!?

 

hi YT,
Welcome to AAC.
Look thru this PDF, covers Differential and Common Mode electrical noise.

E

 

hi YT,
Welcome to AAC.
Look thru this PDF, covers Differential and Common Mode electrical noise.
E

Thank you very much for help,
Why do you thing they crossed the Line and neutral at that point (after choke)!? does it signify anything!?