A method and circuit arrangement dynamically calibrate a photosensitive
control for a light source that includes a voltage divider circuit
coupled to a resistive light detector and configured to output to a
comparison circuit a variable voltage signal that varies with the
resistance of the resistive light detector. To calibrate the
photosensitive control, a variable impedance circuit in the voltage
divider circuit is adjusted to null out any changes in voltage caused by
feedback from the controlled light source. The amount of correction is
proportional to the amount of light feedback. Based on the amount of
correction needed, a new reference voltage is selected that will
accurately detect the next dusk to dawn transition while the light
feedback is present.