Secondary-side snubber

Am 22.08.2018 um 10:36 schrieb Piotr Wyderski:

EMI in first place. Supression of transients caused by reverse recovery of diode and leakage inductance of the transformer.

- Udo

Piotr Wyderski wrote

Maybe it damps RF ringing in the transformer a bit, R3 C5 only works at high frequencies, 300 pF, do not know what the switching frequency is. That is a bit in contrast with C8 470 uF that has to have a good ESR for the 300 pF to make much difference, I would then put 100 nF poly in parallel with C8... Maybe it has a shielded output cable? That capacitance would help too.

It R3 C5 does decrease the switching time on the diode a bit too. Yes it will likely radiate a bit less...