[Amps] Plate Cap Capacitors

Harold B. Mandel ka1xo at juno.com
Thu Jun 23 18:40:23 EDT 2005


Dear Mike,

The request you sent regarding "Plate" capacitors
hopefully is talking about the Plate D.C. blocking
capacitor.

A famous Italian ham has a web-based instruction
on R.F. capacitors, please forgive my not recalling
his call, but essentially, he says that the plate blocker
should measure around ten thousand puff (!)

The important item to remember is the capacitor's
ability to conduct R.F. amperage, which is its KVaR
rating.  Small caps have very low KVaR, (<1A),
so be very careful.

Additionally, paralleling caps at the blocker is an
invitation for them to form a resonant circuit unto 
themselves, which will wipe out your finals.

Best is to calculate the capacitance needed,
double or triple the D.C. anode voltage as
a rating, and apply a ceramic vacuum, glass
vacuum, or ceramic doorknob with the
correct KVaR ability.

Look at http://www.somis.org for more info.

Hal Mandel
W4HBM


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