2141smh@aluxe.UUCP (S. M. Henning,) (01/22/85)
**** **** From the keys of Steve Henning, AT&T Bell Labs, Reading, PA aluxe!2141smh > I've also heard that light bulbs that last forever can be made > you can insert a diode in the line to effectively halve the power > > You can also buy 130V bulbs to accomplish much the same thing. Don't get overwhelmed by any of these options. They only cut the efficiency of the lamp so you spend more on electicity than you now spend on replacement bulbs. This assumes that you use a higher wattage bulb to get the same light output. Otherwise use a lower wattage bulb and save electricity anyway. These devices like diodes, 130 volt lamps etc. cause more of the electricity to be wasted on heat and less used to produce light. Now in the winter the heat is not wasted usually, but in the summer the heat costs you double if you aircondition. The only way to come out ahead is to use high effieciency lamps like flourescents arc lamps, etc. No trick to make a tungsten lamp last longer saves money. It is only advisable for lamps which are difficult to replace or for emergency use.
doug@terak.UUCP (Doug Pardee) (01/25/85)
OK, since nobody else has piped-up, I'll mention it.
If you want longer life light bulbs, go down to your local store and
buy some. Most of the big manufacturers already produce bulbs that
operate at somewhat reduced efficiency but give considerably longer
life. Brands like Turtle-Light (tm, no doubt). GE Long-Life (ditto).
I feel a flame coming on...
The easy way to make a light bulb last forever is to disconnect the
power to it. This lowers both the electric bill and replacement cost!
Sheeesh! How cheap can people get? If I won a lifetime supply of
light bulbs on a game show I don't think that I'd be very ecstatic!
I musta spent 5 bucks on light bulbs last year, maybe more!
--
Doug Pardee -- Terak Corp. -- !{hao,ihnp4,decvax}!noao!terak!dougdavis@hplabs.UUCP (Jim Davis) (01/30/85)
> **** **** > From the keys of Steve Henning, AT&T Bell Labs, Reading, PA aluxe!2141smh > I've also heard that light bulbs that last forever can be made > you can insert a diode in the line to effectively halve the power > You can also buy 130V bulbs to accomplish much the same thing. Here's one point that hasn't been made yet. The use of a diode changes the current going through the bulb from AC to pulsating DC. If that current is smoothed out (e.g. a full wave rectifier and/or a capacitor) then one has direct current. One of the causes of light bulbs burning out is the stress on the coils in the filament caused be electro-magnetic interaction (though startup shock is still a big killer). -- ---------------------------------- Jim Davis (James W Davis) Email: {any_of_the_biggies} !hplabs!davis Arpa: davis%hp-labs@csnet-relay ----------------------------------
jeff@rtech.ARPA (Jeff Lichtman) (01/31/85)
> > **** **** > > From the keys of Steve Henning, AT&T Bell Labs, Reading, PA aluxe!2141smh > > I've also heard that light bulbs that last forever can be made > > you can insert a diode in the line to effectively halve the power > > You can also buy 130V bulbs to accomplish much the same thing. > > Here's one point that hasn't been made yet. > The use of a diode changes the current going through > the bulb from AC to pulsating DC. If that current > is smoothed out (e.g. a full wave rectifier and/or > a capacitor) then one has direct current. One of > the causes of light bulbs burning out is the > stress on the coils in the filament caused be > electro-magnetic interaction (though startup shock > is still a big killer). > -- > ---------------------------------- > Jim Davis (James W Davis) > Email: {any_of_the_biggies} !hplabs!davis > Arpa: davis%hp-labs@csnet-relay > ---------------------------------- The Lawrence Hall of Science in Berkeley has an exhibit on saving electricity. They claim that pulsing an incandescent light on and off doesn't affect its life very much. They have two lights running next to each other, one pulsing about once a second with a 50% duty cycle, and the other running normally. They claim that empirical evidence shows that the life of an incandescent lamp (measured in hours of light produced) is not affected by pulsing. -- Jeff Lichtman at rtech (Relational Technology, Inc.) aka Swazoo Koolak
rbc@houxu.UUCP (R.CONNAGHAN) (02/02/85)
I once had a man who knew light bulbs say that there was a failure mode called "tungten migration". The material in the filiment "migrates" in the direction of the current. This causes diameter reductions in the light bulb filiment. Which causes higher resistance and heat at that spot. And the bulb burns out. The effect is worse for DC and less for AC.. Threrefore running a light bulb on half-wave AC (i.e. DC) may in fact reduce the life of the bulb. -- Robert Connaghan Microprocessor Group AT&T Bell Labs - Holmdel, N.J. houxu!rbc
ron@brl-tgr.ARPA (Ron Natalie <ron>) (02/06/85)
> I once had a man who knew light bulbs say that > there was a failure mode called "tungten migration". > > The material in the filiment "migrates" in the direction of > the current. This causes diameter reductions in the light bulb > filiment. Which causes higher resistance and heat at that spot. > And the bulb burns out. > Also, the tungsten actually boils off. If we fill the bulbs with a halogen we can get the tungsten deposited back on the filiment. I used to be able to explain how this works, but I've forgotten. -Ron
sbt@cbosgd.UUCP (Shirley B. Tobias) (02/07/85)
> Sheeesh! How cheap can people get? If I won a lifetime supply of > light bulbs on a game show I don't think that I'd be very ecstatic! > I musta spent 5 bucks on light bulbs last year, maybe more! Come on--it's not the bucks for most people--it's the inconvenience! I like long-life bulbs for difficult-to-reach places like porches and overhead, etc. Dig? Shirley Tobias cbosgd!sbt Bell Labs, Columbus, OH
2141smh@aluxe.UUCP (S. M. Henning,) (02/08/85)
> Also, the tungsten actually boils off. If we fill the bulbs with > a halogen we can get the tungsten deposited back on the filiment. > I used to be able to explain how this works, but I've forgotten. > The tungsten forms a tungsten-halide at lower intermediate temperatures. The tungsten-halide is a gas and carries the gas back to the filament where the heat decomposes the tungsten halide into tungsten which is deposited on the filament and halogen gas which free to do it again as needed.