Please find attached file and help me to calculate the value of capacitor & Resistor for R-C Snubber. For the frequencies of 20KHz & 50KHz. Please also provided a simple formula.
Snubber dimensioning depends on transformer stray inductance. A design criterion could be a from maximum overvoltage at the MOSFET. As power MOSFET usually have the ability to absorb overvoltage in normal operation, it must not be absolutely necessary. If not knowing stray inductance values by design, empirical dimensioning is probably most simple.