"steve" <stevesemple@xxxxxxxxx> wrote in message
> I was reading a web site that has information about light bulbs. Here
> is a quote relating to a question I wanted to ask.
> -- Quote ---
> "Reducing the voltage applied to a light bulb will reduce the filament
> temperature, resulting in a dramatic increase in life expectancy.
> One device sold to do this is an ordinary silicon diode built into a
> cap that is made to stick to the base of a light bulb. A diode lets
> current through in only one direction, causing the bulb to get power
> only 50 percent of the time if it is operated on AC. This effectively
> reduces the applied voltage by about 30 percent. (Reducing the voltage
> to its original value times the square root of .5 results in the same
> power consumption as applying full voltage half the time.) The life
> expectancy is increased very dramatically. However, the power
> consumption is reduced by about 40 percent (not 50 since the cooler
> filament has less resistance) and light output is reduced by reduced by
> about 70 percent (cooler filaments are less efficient at radiating
> visible light)."
> My question is really just a just wondering kind of question. I have no
> interest in doing this.
> I have seen the type of "Savings " devices written about above. Would
> the same thing be achieved if I simply took a diode of the proper
> rating and put it in line in one of the wires running to an
> incandescent light bulb?
Yes, you would get the same effect. Unless the bulb is in a hard to reach
place you would be beter off just reducing the wattage of the bulb. The
calculations I have seen (not verified) say you will save more on
electricity than the extra bulb replacements will cost.