[Amps] Question on by-pass capacitor TYPE

[peter chadwick]

Paul,

Polyester film caps aren't that good, because generally, they have too much inductance, the dissipation factor is high so they cannot carry much RF current, and even a 0.1 microfarad ceramic disc with negligible internal inductance but a half inch lead each end will be resonant at about 3.5 MHz. Above there, it all looks like an increasing impedance with frequency.

Inductance and dissipation factor are the real problem.

73

Peter G3RZP