[230vac x SQRT(2)]/0.02==>(325Vac-1.3Vdc)=324Vac/0.02A=16185 k ===>18k
Notice that I miscalculated the Peak voltage in Reply#24 so I corrected it to the above.
Since my calculations were for an opto circuit with the diode across the input of the opto (in parallel with opto led) , I did not subtract the 0.7V diode drop which would apply for a half-wave rectifier circuit (which you must be referring to).
