This is an AC voltage controller.
The bulb has a resistance of 5 Ohm.
I used R = V²/P
Change v and p if you want but make sure the resistance is 5 ohm
Its kept low so as not to cause a significant potential drop across the diac(central 4 bjt's).
Vary R or C to see the change in the bulb voltage. Also look at the way bulb flashes.
