Refined Determination of Lamp Life Time Under Abnormal Conditions.

Consideration is given to the effect of the ambient temperature, supply voltage and type of voltmeter connected to the measuring circuit terminals on the accuracy of lamp life determinations. For fluorescent lamps the accuracy can be enhanced by use of a new device making it possible to reduce the error resulting from measurements of an important parameter, viz. , the supply voltage, and to compensate for the voltmeter error. In addition, the mean root-square error for the fluorescent lamps can be reduced by a factor of 3 to 8 through the use of this device and stabilizing the ambient temperature.