I found a couple of identical .85 uf? oil caps... pulled from microwave ovens.?
I measured each one, and? #1? is .880 uf.? ? #2? is? .892 uf?
In series, they total? .442979684? uf .?
When placed across the? 127 lb Dahl? ?4H? choke, the? choke resonates at 119.56 hz.? ? That's? close enough for this application.? ?Choke is rated for? 3A? CCS.? ?With full bore current flowing, the? choke's inductance will rise a tiny bit.... and? resonant freq? will? increase slightly.? ?Apparently,? resonant choke Z? drops off faster on the low side of resonance? vs the higher side of resonance.?
Another option is to series a pair? of? .9uf? oil caps.? ?With .45 uf? across the choke, it resonates at 118 hz.?
Since I have? 3 x kilovac? ?SPST-NC? 25 kv? ceramic relays, rated at 65A? CCS,? ?I will? wire one of em? across the? choke terminals, then a 2nd one? in one leg of the resonating caps.? ?Plus? my adjustable spark gap across the? choke terminals.? ?Coils are 12 vdc.?
Then, I can? rapidly switch from a plane jane? C? input filter...to a? C-L-C? filter..... to a C-resonant choke - C? filter.? ?A? buddy modeled the? ?C-L-C? config? on? LT-spice.... then again with the? C-resonant choke - C?
config, also on? LT-Spice.? ?Both configs work..and both are overkill.? Ditto with just a plane C filter.?
-132 db? for? the? 120 hz ripple..with? the? C- resonant choke - C? filter? ( 3.66 mv p-p).??
-128 db? for the? ? 120 hz? ripple.. with the? ?C-choke - C? ?filter.? ?( (5.8 mv? p-p).?
PSUD-2? depicts? -131 db for the? C-L-C? ?filter...... and? ?>? -134 db? for the resonant choke.?
The resonant choke is supposed to improve ripple by as much as 40 db.... but that's for a? ?resonant choke setup, like old henry and collins amps.? Those amps are? a resonant choke - C? setup.?
On a C-resonant choke- C? ?filter, resonating the? filter is not buying us very much..another? 4db.? ? I will measure the test results..as I don't really trust the various software? ?models.? ?It's just an experiment anyway.... it's all? gross overkill.? ?I want to see if the software? compares to reality.?
Later... Jim? ?VE7RF
