[Amps] Teflon isolation ?

[Steve Thompson]

Patrick Egloff wrote:
> Hi All,
> 
> Does anyone know the maximum voltage that can be applied to a sandwich 
> isolated by a 0.5 mm thin Teflon sheet ??
> 
> It's to be used in a 144 Mhz anode line.
I've just tried a piece with dc hipot. At 14kV an airgap of about 8mm 
sparks over, so that's the limit of test with the sample I have.

I've had problems with minute bits of swarf puncturing the ptfe and 
causing breakdown, and I've read articles describing how air pockets can 
cause breakdown too. I find 0.8mm ptfe pcb with the copper removed works 
really well as an alternative.

Steve