The circuit is an attempt to give an representation of a ac voltage and its equivalent rms value.
When designing ac circuits this is a critical parameter as components can fail.
The formular for calculation of the peak value of a nominal Vac is:-
Vpk = Vac x 1.414 (square root of 2)
So when the 240Vac is required 339 must be entered into the characteristics of the AC voltage
