Patent ID: 8193732

Claim:
An automatic dimming system for causing an electric light to provide a preselected level of light, the electric light having a gradual light dimming characteristic, the automatic dimming system comprising: an electronic ballast; an automatic dimmer connected in series between the electronic ballast and electric light, the automatic dimmer comprising: a plurality of capacitors having a heating element that affects its capacitance thereby providing an electric current flow reduction to the electric light that allows the electric lights gradual light dimming characteristic to operate; switches to select between the capacitors so as to bury their equivalent capacitance, thereby providing an electric current flow reduction to the electric light that allows a gradual light dimming characteristic of the lamp to operate; and an automatic calibration circuit connected in series with the automatic dimmer, the automatic calibration circuit comprising: a light sensor; a current transformer; a rectifier; a control circuit configured to enter a calibration state, and upon entering the calibration state, receive a signal representing light level from the light sensor and to calibrate the output level of the dimmer in response to the light level.