Bulbs in series is a good method to increase bulb life.  It gets the startup
current way down so they don't blow when turned, and at the same time you are
not wasting your power in resistors.  Tube lights that they put in disco floors,
etc. are a bunch of series bulbs.  They are made so they almost never need to be
replaced.

Now if I could just find some 30 or 60V bulbs so I could rewire the twan and
four bulb fixtures in my house.

Olin Lathrop wrote:

> > What irks me is that the bulb manufacturers could
> > very easily add a 5% wire resistor into their filament
> > designs, and make bulbs that last almost forever.
>
> They are probably more concerned with efficiency.  Incandescent bulbs are
> already hideously inefficient, and adding the resistor makes the overall
> solution even more so.  Note that the efficiency goes down by much more than
> the 5% of the power going to the resistor because the filament runs cooler
> and therefore significantly less efficiently.
>
> The manufacturers already make "long life" bulbs.  It appears that these use
> beafier filaments that run a little cooler.  Note that the light output of
> these bulbs is less than the normal ones at the same wattage.  In
> otherwords, they traded efficiency for life, which is what you are doing
> with the resistor.
>
> The real cost of an incandescent bulb is the electricity it uses (work it
> out, you may be surprised), so most of the time it is cheaper to use bulbs
> with higher efficiency but shorter life.  Of course I'm talking about the
> majority of cases where the bulb is easy to change and nothing catastrohpic
> happens when it goes out occasionally, like in your house.
>
> > They just rip us off in a cold calculated fashion
> > with products designed to last a few weeks!!
>
> I'm no fan of incandescent bulbs, but they certainly last more than "a few
> weeks" around here.  We have 120V mains here instead of 240V.  Do the 240V
> bulbs really last that much shorter or were you exaggerating a bit or do you
> leave your lights on all the time?  Incandescent bulbs are inherently low
> voltage high current devices, and making a good 240V bulb is going to be
> harder than a good 120V bulb.
>
> How about using two 120V bulbs in series?
>
> ********************************************************************
> Olin Lathrop, embedded systems consultant in Littleton Massachusetts
> (978) 742-9014, olin@embedinc.com, http://www.embedinc.com
>
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