[Amps] Power factor and choke vs resonant-choke input supplies

[Peter Chadwick]

Why are you particularly worried abuot the power factor?
Some simulations a colleague did some years back suggests that in fact, the choke shouldn't be resonant, but very close to it, such that the choke looks like a very much bigger inductance rather than a straight resistance at the ripple frequency. This is done for minimum load, as the choke inductance will decrease somewhat as the load increases. That's how I very succesfully use tuned choke input: in addition, I filter in the negative lead, so you don't need to worry about the case to innards insulation n the capacitor when it's reasonable size metal cased oil cap. Incidentally, the chokes were always obtained by a process f scrounging - I've never bought one yet! That includes a massive 10H 1 Amp one set aside for a project....
I believe Tom, W8JI, has some hair raising tales about his first attempts at resonant choke input supplies....
73
Peter G3RZP