I tried *hard* to find a source for a polystyrene cap a couple
years ago, for use in a picoamp integrate-and-dump.
The answer came back "No mas." Several sources said the
film was no longer being made; and only a few cap-makers were
still producing from life-time buys of the raw material.
Digikey shows none, today.
That led to comparing dielectrics. It was tempting to try
NP0. The dielectric absorption and leakage looked low, but
there wasn't time. We found a PS supplier, ultimately, and
a polypropylene part for back up.
Cheers,
James Arthur
Of course they're no longer offered by the major players, but you can
still get 63V, 160V and 630V rated parts below 10,000pf in both axial
and radial form from distribution (RS, Rapid, ~Mouser~).
They are about as common as commercial tuned circuits....
I see newer offerings in the audio lunatic fringe as well.
The older power components that used to use polystyrene are generally
replaced by films with better temperature limits....
RL
