I've found this method of triggering of the SCR through DIAC and I'm trying to understand it. I was able to figure out the whole trigger circuit and how to compute the values of RC in order to have the desired delay time to trigger the DAC. What I don't understand is how should I syncronize the trigger part with the wave from the line.
simulate this circuit – Schematic created using CircuitLab
After reading the comment of @user287001, isn't something like that almost correct? (suppose that is enough for me to use only an half-wave)