Lighting circuits and luminaires and methods are disclosed which are operable with a phase-cut dimmer. A circuit includes a rectifier having a low side output and a high side output, a switched mode converter including a switch and an inductor, having a high side input connected to a bus rail, and having a configuration to draw current across a complete mains cycle, a controller for the switched mode converter, a filter circuit connected between the rectifier high side output and the bus rail and including a capacitor connected between the high side output of the mains rectifier and ground, and a resistance connected between the low side output of the rectifier and ground. The value of the resistance may be such the RC time constant of the resistor and filter circuit is greater than the time required for any ringing in the circuit to fall to no more than 20 mA.