A lamp includes a voltage controller that converts a line voltage to a desired RMS load voltage. The voltage controller is entirely within a lamp base and uses pulse width modulation to define the RMS load voltage. The voltage controller has a feed-back circuit that adjusts the RMS load voltage to a desired voltage based on a comparison to a preset reference. The voltage converter also includes a switching transistor that pulse width modulates lamp current and that is responsive to the feed-back circuit. The feed-back circuit may be included in a microcontroller that has a time-based signal source that triggers the transistor, a comparator that compares the load voltage to a reference, and a program that adjusts the time-based signal source based on the comparison so as to provide the desired RMS load voltage.