jerry@oliveb.UUCP (Jerry Aguirre) (01/23/85)
> Yes, lights batterys and nylons. There is a way around the light > problem though, you can insert a diode in the line to effectively half > wave rectify the ac current. This will cause the light bulb to burn > dimmer and thereby remain cooler. Heat, or 'burning up', is the > downfall of the filement in every light bulb. To maintain light output, > you install a higher wattage light bulb which still burns cooler that it > is designed to burn out at. This will cause most light bulbs to last > about 10 times longer than they are spec'ed to (as if I have measured it > :-). > Dan (my 4-year old still knocks the lamps over) Schmidt > Hewlett-Packard > {ihnp4 | hplabs}hpfcla!dgs Yes you can make a light bulb run longer by reducing the power to it. A diode or a higher voltage lamp (220 lamp on 110 voltage) will make the bulb last a long time. The problem is that it will cost you in electricity. The effeciency of an incandesant lamp is some kind of logrithmic function of the voltage, decrease the voltage 50% and you can get a 70% decrease in light output. You could be using twice the electricity to get the same amount of light. Light bulbs are manufactured with total cost in mind. The cost of the bulb is probably small compared to the electricity it will consume in its expected lifetime. The reduced power approach only makes sense if changing the bulb is difficult or is little used. A lamp located at the top of a stairwell or in an attic might be more trouble to change than the cost of the extra electricity. There is an approach that extends life without extra electrical costs. It uses a varisistor in series with the bulb. This turns the bulb on gradually but supplies full power after warm up. This eases the thermal stress on the filiment. Bulb life is more proportional to the number of times it is turned off and on than burn time. A bulb on a flasher can burn out after only a few hours of operation. Jerry Aguirre @ Olivetti ATC {hplabs|fortune|idi|ihnp4|tolerant|allegra|tymix}!oliveb!jerry
roy@phri.UUCP (Roy Smith) (01/24/85)
> Bulb life is more proportional to the number of times it is turned off and > on than burn time. A bulb on a flasher can burn out after only a few hours > of operation. > Jerry Aguirre @ Olivetti ATC Yeah, I know that's the theory, but it is also real bad to burn a bulb upside down. I have a light the hallway of my building which is on 24-hrs a day, hanging upside down, and burns out what seems like every other day, but in reality is about every month. -- allegra!vax135!timeinc\ cmcl2!rocky2!cubsvax>!phri!roy (Roy Smith) ihnp4!timeinc/ The opinions expressed herein are mine, and do not necessarily reflect the views of The Public Health Research Institute.
ron@brl-tgr.ARPA (Ron Natalie <ron>) (01/28/85)
> > Yeah, I know that's the theory, but it is also real bad to burn a bulb > upside down. I have a light the hallway of my building which is on 24-hrs > a day, hanging upside down, and burns out what seems like every other day, > but in reality is about every month. Actually the really intersting thing is what the definition of upside down is. Some bulbs are designed to burn base down and some base up. -Ron
stew@harvard.ARPA (Stew Rubenstein) (01/28/85)
> > Bulb life is more proportional to the number of times it is turned off and > > on than burn time. A bulb on a flasher can burn out after only a few hours > > of operation. > > Jerry Aguirre @ Olivetti ATC > > Yeah, I know that's the theory, but it is also real bad to burn a bulb > upside down. I have a light the hallway of my building which is on 24-hrs > a day, hanging upside down, and burns out what seems like every other day, > but in reality is about every month. > -- > phri!roy (Roy Smith) When I was doing theatrical lighting, we had certain instruments which took bulbs *designed* to be burned upside down. If burned base-down, they burned out much more quickly. I guess the makers of light bulbs figure this is too difficult a concept for the average consumer to deal with... -- ----------------------- Stew Rubenstein UUCP: ihnp4!harvard!stew Harvard Chemistry ARPA: stew@harvard
normand@tekig1.UUCP (Norman Dodge) (01/28/85)
Lightbulb lifetime is also influenced by lightbulb quality. They are NOT all the same! Over the last 18 years I have kept accurate records of all brands used in my house. This was done by penciling the brand of the replacement bulb and the date of replacement in the light fixture. The result is that Sylvania brand bulbs burned 75% as long as Westinghouse. And Westinghouse lasted only half as long as General Electric. For the past 5 years we have been using GE exclusively. As mentioned in previous articles, reducing the voltage on the bulb can greatly increase the lifetime. This can be accomplished by using bulbs rated at 130 volts or by the use of a resistive device of some nature in series with the bulb. Another good method is the use of light dimmers in place of normal light switches. Dimmers, especially the low cost ones, do not usually put the full power line voltage across the bulb. With the dimmer full on, the bulb operates at a lower voltage and will last longer. When the dimmer is set to a lower level, the bulbs may last for many years. We have a dimmer in our bathroom and one on the light by our driveway. The four bulbs in the bathroom have been used daily for the last 18 years and are still the original bulbs! The driveway light is on every night from dusk to dawn and has been replaced 4 times in 18 years. One of these times was because rain water leaked on it and cracked it, and another was when it was shot by a BB gun.