An apparatus is disclosed that is capable of delivering substantially constant power to a luminous load with variation in the input voltage and the environment temperature. The apparatus may be further adapted to vary the power supplied to the luminous load based on changes in the input voltage produced by a phase control dimmer or external device. Additionally, if the input voltage is changed due to a user controlling a dimmer device to control the brightness of the luminous load, the apparatus is able to control the power delivered to the load in response to the dimmer device. Additionally, the apparatus is adapted to allow the luminous output light intensity to be controlled by changes in a remote control voltage source or variable resister and draws near unity power factor power from the AC input throughout the dimming range when not used with phase control dimmer. The remote control or variable resistor can operate simultaneously with a dimmer to achieve multiple controls for the light output.