Being my first time to use a Triac and a Diac to control an AC signal, I read many questions/answers in this forum related to DIACs controlling TRIACs, all being very helpful.
Now, I see in a MOC302 DIAC's datasheet page 8, something that I dont understand:
Won't the Triac conduct if the R1 is low enough? I do not understand the reason to use R1 there, it should be an open circuit in R1, so that the DIAC could be in series with Triac's Gate.
And I saw the same conficuration at this question:
But no one commented why his R6 is there.
Regarding mainly @Spehro Pefhany's answer, since the R1 makes the Base less sensitive,
I guess R1 has to be high enough so that It wont cause the Triac to conduct when the photo Diac is off and AC voltage is on this stage:
So if Triac conducts at Holding current= 20mA, we need the Resistor to be at least (more than) R=100/0.002=50kOhms, Right?
(As long as the voltage on its gate does not exceed (lets say) 1.3V where it conducts, the 50Kohms will do the job, but still, I do not know how to calculate if the Voltage at the gate will surpass 1.3V on the above schematic with R1=50K)