Calculations of the instantaneous luminous flux for the high-pressure mercury lamp using equivalent conductance models

Calculations of the luminous flux which is an output of discharge lamps are necessary in the overall analysis of the operating circuit for such lamps. In this paper, we calculate the instantaneous luminous flux of a 40 W clear mercury lamp operated by simple two circuits: one is a resistance type operating circuit, and the other a chopper type operating circuit. After the discussion on the relationship between the lamp’s instantaneous conductance and the temperature of the arc plasma in discharge lamps, the instantaneous temperature of the arc plasma is determined by the lamp’s instantaneous conductance which can be calculated by using the lamp model equation. Then, the instantaneous luminous flux, which depends on the sum of the line spectral intensities, is calculated by this instantanous temperature of the arc plasma. Finally, the usefulness of this calculation method is discussed, comparing the calculated results with experimental results.