In parallel with a 10nF cap ...
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On Mon, 15 Feb 2021 at 03:02, Jim Shorney <jshorney@...> wrote:
And yet here we have two electrolytics in an RF circuit in a legendary
piece of ham gear. I asked an actual rocket scientist about it and he
didn't think it was anything unusual.
73
-Jim
NU0C
On Mon, 15 Feb 2021 00:55:06 +0100
"Dragan Milivojevic" <d.milivojevic@...> wrote:
That makes no sense whatsoever.
On Sun, 14 Feb 2021 at 23:14, Manfred Mornhinweg <manfred@...>
wrote:
And what's the best bypass cap? Well, a single, plain, cheap aluminium
electrolytic!
Attached is the impedance plot for a 47?F, 25V electrolytic cap,
measured
with lead lengths compatible with mounting it snugly on a PCB. Their
narrow
pin spacing helps a lot in keeping their ESL low. I kept the same
scale to
make comparison easy.
YES, a single 47?F electrolytic is a much better bypass cap than a
parallel combination of two ceramic caps of different values! Even in
the
low VHF range!
The problems with electrolytic caps is that their ESR rises with age,
and
rises much faster if they run hot, or if they have to carry large
ripple
current. So they can't be applied in every situation. But in situations
that are kind to them, they are the cheapest and easiest way to get an
excellent wideband bypass.
