Methods and apparatus for powering a dimmable ballast operating with LED light source(s) are provided. In one embodiment, the ballast circuit includes sections comprising: power input, full wave bridge rectifier, voltage regulator, integrated circuit driver, switching transistors, bypass capacitor, resonant circuit, rectifier diodes, and an LED light source. The resonant circuit receives energy from the voltage source and the bypass capacitor every switching cycle, and provides current to the rectifier diodes and one or more LEDs for generating light. Further, because the current flowing into the resonant circuit is substantially sinusoidal and in line with the input voltage, the circuit exhibits a desirable power factor. The ballast circuit can also effectively dimmed over a wide range using a phase angle dimmer, allowing further energy savings.