Phil Allison wrote:
"UCLAN"

Please do not confuse Power Factor Correction (PFC) with power supply
efficiency. They are two separate items.

** OK so far.

PFC can be either active or passive,

** Hmmmm...

but usually alters the highly capacitive input of SMPSs.


** TOTAL ******** !!!

They are not capacitive, there is no phase angle.

Active PFCs correct WAVEFORM distortion.


If you take the waveform of the current into a conventional SMPS, and
split it into its harmonics, you'll find that the fundamental leads the
voltage. This because the PS's capacitor is charged during the rising
side of the input waveform.

Looks like a phase angle to me.

By making the current proportional to the voltage, active PFCs both
minimise the waveform distortion, and correct the phase angle.

Sylvia.