Polycarbonate Caps

[Grant Richter]

The Illinois Capacitor company makes a line of polycarbonate caps with
temperature coefficient (tempco) of 50 ppm. I'll have to dig out the book,
but that is the best I have seen as far as temperature stability. Good
metal film resistors have tempcos of 50 ppm. The primary concern for VCO
timing caps is tempco, (as I get it from Electronotes) and polycarbonates
are speced for Electronote VCOs. They are also speced directly on the
schematics for Buchla VCO's.