[Amps] HV feed through capacitor

[Steve Thompson]

One of YU1AW's designs gives a size of 80x150mm for the pcb 
capacitor. Allowing for the dielectric that's in the region of a 
quarterwave x halfwave. On top of that it's lossy at 432 so if 
there's any significant rf for it to handle there's all sorts of 
things could happen.

Something made from PTFE based pcb or ptfe sheet could be an 
alternative.

Steve

> Yeah, it's for a 432 amp. At that frequency the series inductance of a 
> single "normal" disc ceramic is enough to prevent good bypass action. 
> Results in a lot more 432 energy running around on the HV line than I like.
> 
> YU1AW calls for a cap made from FR4 PCB material. Even though I etched 
> back the edges and hi-potted the thing, it still managed to prove that 
> my HV supply fault mitigation system actually works!