Compact Fluorescent Lamp (CFL) and LightEmitting Diode (LED) are energy efficient light sources. However, they have a disadvantage that they cannot be directly dimmed with a triac dimmer. This article briefly explains the incompatibility issues, and suggests a CFL ballast circuit to overcome this disadvantage. The ballast is based on resonant mode topology, with additional circuitry for triac interface and dimming control. Furthermore, this article also presents, with few modifications to the CFL ballast circuit, an LED driver circuit that is dimmable with triac dimmer. Experimental results show that both proposed circuits are able to be dimmed down close to 10% of the light output.