wrote:
Jim - NN7K wrote:
Always wanted a 1 FARAD (or bigger) capacitor!
Where can you buy one?? (Short of buying a
"Charged "one, I.E. Storage Battery)? Oh
well only 6 Months to April First!
Jim NN7K


Richard Clark wrote:



Not unless you can assemble a couple hundred Farads (note the complete
absence of pico, nano, or micro in that Farads). The short version is
DON'T GO THERE.

73's
Richard Clark, KB7QHC

Why settle for a measly 1 F when you can have 50 F?

Go to www.digikey.com and search for 283-2511-ND.

--
Jim Pennino

Remove .spam.sux to reply.

And if the 5W output rig draws an amp on transmit, that 50F cap will
run it for 50 seconds with a one-volt drop. Compare that with an
inexpensive little 7Ah 12V gel-cell battery that will run it for
probably five hours. Caps may make sense to smooth over short pulses
of current, but seem like a poor solution for storing long-term energy.

The OP's question is so basic that I wonder if he's pulling our
collective legs.
--How many amps does the rig draw in transmit? In receive?
--How long do you want the aux power source to run it?
----how many hours of transmit; how many hours of receive?
--That tells you the minimum Ah rating for the aux battery.
--Use I = C * dV/dt and how much voltage drop you can stand
to figure the size capacitor you'd need to do the same thing
for an aux capacitor (and then discard the idea in favor of a
much cheaper battery).

Cheers,
Tom