The 1A loading occurs every 2.2 seconds (or longer). Best I can tell it is
actually a series of ten pulses, 3mS each, lasting a total of .3 seconds.
I need to run this from a battery pack. Initial attempts with 4xAA alkaline
dropped to near zero volts when pushed to 1 amp. I know alkalines are the
worst for high draw circuits so I'll try a NiMH pack when I get home. I'm
not concerned with battery life since this is a portable test instrument
that will only be used occasionally for an hour at a time. I'd like to have
caps provide this current but will go to C or D cells ($$$ in NiMH) if that
is the only solution.
How about putting 2 Alk "D" cells to power the 3.3v module directly and
use a very simple charger circuit to keep the D cells charged? I did
something similiar with an electric clock that would only work on a
really fresh cell; I kept the cell charged so it worked for years
without discharging.
If you want to go the cap route, I use a similiar circuit to run
electric fencers. They take a big current surge every second. I
usually use a big (about 2000 mf) cap to provide the surge. A quick
test to see if it is big enough is to disconnect the power source (in
my case a junk 12 v auto battery) and see how many pulses I get out of
the stored energy in the cap. If I can get about 3 pulses then I figure
the cap is big enough.