A lamp includes a voltage conversion circuit that converts a line voltage to a desired RMS load voltage. The voltage conversion circuit is entirely within a lamp base and uses pulse width modulation to define the RMS load voltage. The voltage conversion circuit includes a bridge that supplies the RMS load voltage to a light emitting element, a switching transistor that pulse width modulates a current supplied to the bridge, a timer connected to a gate of the switching transistor to turn the switching transistor on and off at a rate that defines the RMS load voltage, an analog-to-digital converter that converts the RMS load voltage to a digital signal, a comparator that compares an output from the converter to a preset reference value, and a circuit that adjusts the timer in response to an output from the comparator.