I would like to build an AC lamp PWM controller with a 555 and a triac. I don't really understand the 555, maybe I haven't put in enough effort. I'm really busy with my studies, and sometimes my studies interfere with my passion. Anyway, my uncle is an engineer and he told me the duty cycle of the 555 equals to the size of the capacitor times the resistance of the resistor, so all I need is a potentiometer right?