The present application discloses a method and apparatus for providing an isolated set point from an input signal. The set point can control the amount of power applied to a lamp via a lamp ballast. An AC output signal from the ballast powers a dimming circuit. The AC signal is coupled across an isolation transformer and subsequently converted into a DC signal. This DC signal is loaded by a variable resistor, which creates a voltage differential across the resistor. This voltage differential is then seen across DC input terminals of the ballast, and it is across the DC input terminals that the set point is created. By varying the value of the resistor, the ballast set point is varied ultimately changing the power that is applied to the lamp by the ballast.