a little help with capacitive power supply values

[Pic_User]

Hi all

I would like to incorporate a transformer-less capacitive power supply in the project I am busy with.
I found this app note on the microchip site
[HTML]http://ww1.microchip.com/downloads/en/AppNotes/00954A.pdf[/HTML]

What's confusing me is deriving the values for a 220V 50Hz supply.

I can't seem to fugure out where the values for R1 and C1 are initially derived...are the just assumed and we calculate the rest from there?

Also hat is not clear is the WATTAGE for R2 1M in figure 10 nor for VR1 or the MOV.

I hope someone can offer some help here

Kind regards
Dennis

Hi Dennis,

Transformerless Power Supplies are extremely dangerous and discussed in many threads.
http://www.picbasic.co.uk/forum/showthread.php?t=3265
http://www.picbasic.co.uk/forum/showthread.php?t=3898

Most here would advise against them.
-Adam-