A single-pole (two-wire system) phase-controlled trailing-edge light-modulating circuit comprises a full-bridge rectification circuit, a power supply circuit, a light-modulating control circuit, and a voltage detection circuit. The light-modulating control circuit utilizes a CMOS chip and controls a field effect transistor by detecting specific voltage level to perform a trailing-edge phase control action for modulating light output of resistively and/or capacitively loaded light bulbs, e.g. LED light bulbs. The light-modulating control circuit connects to various lighting loads in series. In addition, the triggering circuit and the power supply circuit of are independent to avoid mutual restrictions to each other that might affect the adjustment of the maximum conduction phase angle.