Re: DRSSTC Noise source found

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Ed Phillips <evp@xxxxxxxxxxx>

">Its Probably the inductance of the caps resonating with the C and not
>related to the fact the dielectric is polypropylene.

Yep!!  I have heard poly turns into resistive mush at say 10MHz, but
that
is typically far past poly cap's resonant frequency.  We have fancy
spectrum analyzers at work, but they have more buttons than I have brain
cells 0;o))  Maybe in a dull moment I could try to measure them if I can
get someone there to help me."

	Polypropylene isn't a bad HF dielectric.  Problem is undoubtedly in
method of construction and lead inductance.  Of course, lots of smaller
capacitors (of any type) in parallel will have a lot less ESR and higher
resonant frequencies, leading to better bypassing performance.

Ed