The discussion clarifies the relationship between AC and DC ratings of capacitors, specifically addressing microwave capacitors rated at 2100 Volts AC. It is established that the DC rating of AC capacitors is typically 3-5 times higher than their AC rating. Additionally, it is noted that as the AC frequency increases, the working voltage rating decreases, which is critical for understanding capacitor performance in varying conditions.
PREREQUISITESElectronics engineers, hobbyists working with capacitors, and anyone involved in designing or troubleshooting AC and DC circuits.
http://www.electronics-tutorials.com/basics/working-voltage-capacitance.htm"This working voltage is expressed in terms of DC but the AC equivalent is about only one half of that DC rating. As the AC frequency increases the working voltage rating decreases further still.