ELECTRONIC CIRCUIT AND IMAGE PROJECTOR CONTAINING THEREOF

摘要

PURPOSE: An electronic circuit and image projector containing the electronic circuit is provided to be capable of controlling the luminance through the lamp life and using a sensor of an easier structure and thus an inexpensive sensor. CONSTITUTION: An electronic circuit for operating an HID(High Intensity Discharge) lamp(322) comprises a lamp ballast(110), a brightness sensor(130), and a filter(140). The lamp ballast(110) is constructed as a control unit and serves to provide and control a lamp current for operating the HID lamp(322) in response to a control signal, so that the quantity of light given off by the HID lamp at the location of the brightness sensor(130) is constant in the medium term.