Light-Bulb Saver Performance

Information is provided on the characteristics of the incandescent lamp connected in series with a diode. The reduction in lm/W, a drastic decrease in color temperature, and the injection of dc in the power network disadvantages that outweight the only true benefit derived from this connection: a much longer lamp life. Theoretical calculations supported by experimental measurements prove that to keep the illumination constant the lamp wattage must be more than doubled. A simple economical analysis indicates that the cost of typical incandescent lamps, lasting 750 h or more, is exceeded by the cost of additional losses. The most serious drawback of this method is the injection of dc and current harmonics into the ac supply network.