Light Bulbs

[Tywais]

If what you say is correct (& I don't doubt you), a diode installed as a half wave rectifier will not necessarily increase the life of a lamp.

Yes, you are getting the same peak voltage but only half the time reducing the 'average' power and therefore the temperature of the bulb considerably. 10 msec on 10 msec off (50Hz), don't think the bulb temperature would change that much in that short of a period of time for thermal shock to be an issue.

The reason I suggested it was probably a diode is due to the fact that the resistor would have to be quite large for the power drop it would need. For example on your 5% example using a 200 Watt bulb would require about a 10 Watt resistor. Doesn't seem likely in the space of the discs I've seen.

[Tywais]

Some more information on 'the disc'.

"Several small disc-shaped devices were marketed for insertion into the socket, below the bulb, to reduce the lamp energy by controlling its applied voltage. (See accompanying photo.) They went by various names: Energy Button, Lite Preserver, Bulb-Miser, Lite-Bulb Saver, etc.

Related Results

How did they work? Some were simply half-wave rectifiers using silicon diode technology. Full details appeared in the 1986 IEEE Transactions, in a paper by Alexander Emanuel titled "Light-Bulb Saver Performance." The diode in series reduces lamp voltage to 71 % of normal, and the electric power dissipated in the bulb drops to 59% of normal (taking into account the reduction in filament resistance). Besides the energy saving, the lamp filament temperature is reduced such that lamp life expectancy theoretically increases nearly a hundredfold.

This method of lowering power demand poses several inherent problems. The most obvious one is that the light output is reduced as well, by almost 70%. To provide the same level of illumination as before, larger (higher wattage) lamps must be used-- quickly wiping out the energy saving. "

Source: http://findarticles.com/p/articles/mi_qa37...302/ai_n9222171

[Tywais]

Some more information on 'the disc'.

"Several small disc-shaped devices were marketed for insertion into the socket, below the bulb, to reduce the lamp energy by controlling its applied voltage. (See accompanying photo.) They went by various names: Energy Button, Lite Preserver, Bulb-Miser, Lite-Bulb Saver, etc.

Related Results

How did they work? Some were simply half-wave rectifiers using silicon diode technology. Full details appeared in the 1986 IEEE Transactions, in a paper by Alexander Emanuel titled "Light-Bulb Saver Performance." The diode in series reduces lamp voltage to 71 % of normal, and the electric power dissipated in the bulb drops to 59% of normal (taking into account the reduction in filament resistance). Besides the energy saving, the lamp filament temperature is reduced such that lamp life expectancy theoretically increases nearly a hundredfold.

This method of lowering power demand poses several inherent problems. The most obvious one is that the light output is reduced as well, by almost 70%. To provide the same level of illumination as before, larger (higher wattage) lamps must be used-- quickly wiping out the energy saving. "

Source: http://findarticles.com/p/articles/mi_qa37...302/ai_n9222171

[elkangorito]

If what you say is correct (& I don't doubt you), a diode installed as a half wave rectifier will not necessarily increase the life of a lamp.

Yes, you are getting the same peak voltage but only half the time reducing the 'average' power and therefore the temperature of the bulb considerably. 10 msec on 10 msec off (50Hz), don't think the bulb temperature would change that much in that short of a period of time for thermal shock to be an issue.

The reason I suggested it was probably a diode is due to the fact that the resistor would have to be quite large for the power drop it would need. For example on your 5% example using a 200 Watt bulb would require about a 10 Watt resistor. Doesn't seem likely in the space of the discs I've seen.

Thanks for that Tywais . It appears as though half wave rectification will increase the life of an incandescent lamp at the cost of Lumens.

Nonetheless, the most efficient way to do the same is simply by reducing the supply voltage by at least 5% or better yet, 10%. This is best done with a good old fashioned transformer (98% efficient at a minimum of 0.8 of full load). Current limiting will also have a similar effect (series choke - reactive dimmer). At least coils don't infect the electrical system with nasty harmonics.

[Naam]

during construction period of my home i was busy replacing light bulbs in two different rented homes. in my own home virtually all my lights are on dimmers and in 15 months i had to replace one single bulb. the dimmers are never turned on fully. unfortunately i was not able to find energy saving dimmers in Thailand but the available ones save the hassle of replacing bulbs in lamps mounted in 3.60 meters high ceilings.

in my former home in Florida we had tremendous voltage fluctuations, Home Depot made huge profits selling light bulbs to me and i kept on climbing up and down on a ladder changing light bulbs and cursing Florida Power & Light. two years later i brought a suitcase from Germany full with 220V bulbs with different wattage. et voilà... problem solved!

[Theyreallrubbish]

during construction period of my home i was busy replacing light bulbs in two different rented homes. in my own home virtually all my lights are on dimmers and in 15 months i had to replace one single bulb. the dimmers are never turned on fully. unfortunately i was not able to find energy saving dimmers in Thailand but the available ones save the hassle of replacing bulbs in lamps mounted in 3.60 meters high ceilings.

in my former home in Florida we had tremendous voltage fluctuations, Home Depot made huge profits selling light bulbs to me and i kept on climbing up and down on a ladder changing light bulbs and cursing Florida Power & Light. two years later i brought a suitcase from Germany full with 220V bulbs with different wattage. et voilà... problem solved!

I recently had a chat with a UK engineer who told me that in the UK he marks the date when he puts in a light bulb. If the bulb blows before its rated lifetime he takes it back and gets a free replacement! All the stores do this, Homebase, B&Q etc. Presumably its a manufacturer warranty. Since Homebase is owned by Home Depot I think you should have been able to do the same in the US.

[dingdongrb]

Light bulbs do not 'die out' or 'burn out'. The reason they quite working is because the filament has been damaged. The rectifier you mention (disc) protects the filament when there is high rush (surge) of current. The rush of current is when the switch is first turned on and electricity goes to the light. Ever seen a light stop working after it's been on for awhile. No, its filament is damaged when it's first turned on and there is excessive current.

Try LED lighting. It is the technology of the future. Much less energy consumption (save $$$ on your electric bill), it is environmentally safe (no mercury content), much truer natural light provided, will last for 10 years. Also drop it and it won't shatter.

[chiangmaibruce]

We have the same problem with bulbs dieing frequently (small house in the 'burbs). Usually use Phillips as I thought they were better quality. We had very shoddy electricians 'help' with our renovations, so I have always put it down to that.

I have also had a lot of problems with the cheap&nasty screw mount light sockets originally installed in our house (poor connections mainly, but also some melting/blistering of plastic parts). We use max bulb of 100w and not in an enclosed fitting. I have brought some bayonet mount sockets from Australia and this has fixed that problem.

Another issue with the screw mount sockets is the frequency of the glass bulb separating from the metal collar - usually happens when you try to remove them after they have popped!

With the long-life/low energy bulbs - can you get bayonet mounted ones in Thailand? I haven't seen any in Chiang Mai

- CB

[paulfr]

Light bulbs do not 'die out' or 'burn out'. The reason they quite working is because the filament has been damaged.

With all due respect ..... this is patently false.

I worked at Westinghouse Research Labs; Lamp Division so I know a little bit about this subject.

All incandescents "evaporate" the filament which is why the lamp turns black

near end of life [EOL in the industry]. So they continually weaken until they

cannot stand the shock of turnon electrostriction and inrush current.

So they fail at that point.

Run an incandesent at 5-10% lower voltage and they will nearly last forever

if you do not cycle them every day. We used to do that with control panel

indicators [lights] in the Particle Beam Accelerator control room in Berkeley

before LEDs came about. This is what that little disc does, in effect.

Cheers

Edited September 9, 2008 by paulfr

[dingdongrb]

All incandescents "evaporate" the filament which is why the lamp turns black

near end of life [EOL in the industry]. So they continually weaken until they

cannot stand the shock of turnon electrostriction and inrush current.

So they fail at that point.

Cheers

All???... Get to reality... http://www.centennialbulb.org/

And I know how Westinghouse was ran, my Mother worked there for over 20 years...

[dingdongrb]

All incandescents "evaporate" the filament which is why the lamp turns black

near end of life [EOL in the industry]. So they continually weaken until they

cannot stand the shock of turnon electrostriction and inrush current.

So they fail at that point.

Cheers

All???... Get to reality... http://www.centennialbulb.org/

And I know how Westinghouse was ran, my Mother worked there for over 20 years...

By the way, what is the EOL on an incandescent light bulb? How come one can take and put a brand new one in and have it die within a few weeks? Must be due that build up of "black" chit...