The Fifteen Watt Tungsten Lamp

The work opens with a concise history of the tungsten lamp’s evolution over the first half‑decade of the twentieth century, noting how manufacturers have repeatedly pushed toward ever‑smaller, lower‑wattage models. Against this backdrop, the author sets out to document the performance of the newest 115‑volt, 15‑watt unit, comparing its lifespan and behavior to larger predecessors. A modest sample size and the practical constraints of early‑industrial testing are acknowledged, reminding listeners that the findings are exploratory rather than definitive.

The middle sections describe a careful experimental program: twenty‑four lamps—half supplied directly by the factory, half sourced from the open market—were measured with calibrated photometers, voltmeters and ammeters. Two life‑tests were run, one under steady, ideal conditions and another employing a vigorous vibration rig to simulate harsh shock. Detailed characteristic curves are presented, and the curious “overshooting” phenomenon receives special attention, offering insight into the lamp’s electrical and luminous quirks. Listeners will gain a clear picture of early electrical‑engineering research methods and the practical challenges of evaluating emerging lighting technology.