Capacitor between High and low voltage sections

[berni80]

Hi,

In an isolated DC/DC that converts high voltage (ie 300V) to low voltage (ie 12V),
is often present a capacitor between High and low voltage sections.

Have you noticed it?
Which is its function?

Thanks

 

[FvM]

In most cases, it's necessary to keep the common mode switching noise generated by the converter within acceptable limits.