For the 220V 50Hz circuit, provided by op, is it absolutely necessary to use 45K ohm resistors? I can't seem to find the given value at local or online electronic retailers. The closest values I have found for 1/2W resistors is 43K and 47K ohm.
I was thinking perhaps connecting 3 15k ohm resistors in series but wouldn't the cumulative tolerances make the difference with using 43K and 47K ohm resistors trivial?
Would appreciate it if someone could point me in the right direction