For the love of whoever you believe. Don't make this circuit unless you ABSOLUTELY know what you're doing.
This it's a capacitive impedance-based voltage dropper that is used to power cheap electronics that are supposed to be not accessible by any personal. AKA sealed behind an insulating casing.
By the way the power factor of this circuit is dog water... the only upside of this circuit is the fact that it is dirt cheap. And that's about it.