Uwe is spot on. The capacitance vs. voltage of the X7R dielectric is not very good. NP0/COG are usually specified for precision timing and filter applications.
NP0/COG also have a much lower temperature coefficient. Andy. On 11 April 2011 15:58, Uwe Bonnes <b...@elektron.ikp.physik.tu-darmstadt.de> wrote: >>>>>> "Kovacs" == Kovacs Levente <leventel...@gmail.com> writes: > > Kovacs> I'm currently designing a power amplifier for the HF (3-30MHz) > Kovacs> radio band. > > Kovacs> I am selecting capacitors for the low pass harmonic filter bank > Kovacs> at the output. My question is what kind of capacitors should I > Kovacs> use? I apply not more then 100V of say 30MHz maximum. > > Kovacs> My best bet is to use X7R capacitors with as much DC voltage > Kovacs> rating as I can get. I don't know if there's any connection > Kovacs> between the DC and AC losses. > > > What value do you need? Try NP0/COG type, even if substantial more > expensive. I guess the X ceramic will introduce more harmonics than it will > filter out... > -- > Uwe Bonnes b...@elektron.ikp.physik.tu-darmstadt.de > > Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt > --------- Tel. 06151 162516 -------- Fax. 06151 164321 ---------- > > > _______________________________________________ > geda-user mailing list > geda-user@moria.seul.org > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
