Discussion on “distortion of alternating-current wave form caused by cyclic variation in resistance” (Bedell and Mayer) New York, February 18, 1915. (see proceedings for February 1915)

Clayton H. Sharp: I could wish that Dr. Bedell would carry his analysis a step further, and apply it to the condition of alternating current operation of lamps. When that is done, a number of other factors evidently enter which introduce considerable complication. As I understand the analysis which is given here, Fig. 1 represents what might be called the statical condition, that is, where the frequency of the alternating current is so low that the temperature changes have time to equalize themselves for each step, so that there is no temperature lag. In other words, it corresponds to what we should have if we carried the filament through a cycle of steps and gave it sufficient time at each step for the temperatures to become steady. In that case, a third harmonic is introduced into the fundamental sine wave, and the third harmonic is so phased as to cause the wave to flatten at the top.