I am designing a Capacitive power supply, I found someone who did the circuit shown in the figure. I don't know what is the usage of the 47 ohm resistor in series with the Zener diode (12V MELF package). Also what is the purpose of the 1uF ceramic capacitor in parallel with Zener diode. I didn't find any one who suggest that. In fact this product is known as the most robust one among its peers.
There is Protection Varistors and inrush resistor, but not included in the schematic.
The question is:
What is the use of this resistor and 1u capacitor? How to make power supply robust? beside the use of varistor and TVS.
I have edited the schematic with adding the other polarity.