21 Jul
2015
21 Jul
'15
6:56 p.m.
On Mon, 20 Jul 2015, Mark J. Blair wrote:
I've often wondered why they even bother to put that polarity stripe on
modern film parts when it doesn't actually indicate the outside foil
terminal. Maybe this is something that has become lost knowledge to
manufacturers over the years to the point where even Vishay/Sprague
doesn't know what that black indicator stripe was actually used for?
On Jul 20,
2015, at 18:02 , Tothwolf <tothwolf at concentric.net> wrote:
I replace wax paper types with polyester (mylar), polystyrene or
ceramic discs, depending on how they are used in the circuit (note
however that for wound foil types, modern replacement parts do not mark
the outside foil, which needs to be at ground potential in many tube
circuits, otherwise the circuit can pick up noise and hum).
Funny that you mentioned that! I just watched a YouTube video today
about how to experimentally determine which lead is connected to the
outer foil for applications where that's important. Modern film caps may
have a stripe on one end, but it doesn't appear to reliably indicate
which lead goes to the outer foil.