Diode in series with light bulb

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)."

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My question is really just a just wondering kind of question. I have no
interest in doing this.
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Reply to
steve
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Yes, since that's precisely what's going on.

However, you need to be particularly aware of the fact that, besides using roughly half the electricity, your bulb will also put out MUCH less light - IME, a 60 watt bulb with one of those things attached to it is reduced to about the output of a refrigerator bulb. Another consideration is the flicker-factor - The claim is that there will be no flicker, but I'll dispute that with my dying breath - Maybe for "Joe Average" there's no flicker, but to *MY* perception, it's there, highly apparent, and *EXTREMELY* distracting. Does that mean I've got "super vision"? Idunno. All I can say for certain is that there is indeed some serious flicker, it'll drive me to distraction in about 20 minutes, and if I don't leave the area, it will induce an all-out "I think I better go lock myself in a dark, soundproof, sealed, odorless, padded room with a drain to puke down for about the next three days so I don't end up killing myself or an innocent bystander" migraine within about an hour.

And *DO NOT* try to use such a gizmo with *ANY* variation of the "replace your incandescent bulbs with our cooler, cheaper-to-run flourescent version" units on th market today - The failure of the ballast transformer when it gets fed DC instead of AC can be quite... Well, let's say "interesting" - If you consider having a lamp start spewing sparks and dribbling molten metal and plastic to be interesting, that is...

(DAMHIKT...)

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Don Bruder - dakidd@sonic.net - If your "From:" address isn\'t on my whitelist,
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Reply to
Don Bruder

Thanks all for your comments.

Yes I wondered the same thing about the flicker factor. I'm not sure how often the /\\/\\/\\ waves alternate ( I know you all know this by heart, I'm a novice) but by cutting it in half or there abouts, has to have some effect. also I wonder out loud, if the half wave can set up some sort of resonance depending on the voltage of the bulb and give an annoying noise ??? I don't know only guessing.

Thanks again

Reply to
steve

Usually 60 Hz (US), and 50 Hz (Europe) - If put to a speaker (through a suitable resistor, of course! Otherwise it's Insta-Fry(TM) time for Mr. Speaker) the socket in the wall would output a low, *LOUD* (unless the resistor was good and beefy) hum.

I imagine it could be possible for a bulb's filament to start vibrating, possibly audibly, but I'd expect it to be an unusual situation, probably confined to specific bulbs from a specific batch of a specific brand. (AKA "I think the odds are against it, but I won't call it impossible.")

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Don Bruder - dakidd@sonic.net - If your "From:" address isn\'t on my whitelist,
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Reply to
Don Bruder

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.

Reply to
Ralph Mowery

Steve.. I have done this (added diode in series) . Had a porch light that always had a short life. I installed diode and a higher wattage bulb to get the same brightness. No more problems. W W

Reply to
Warren Weber

Ive been told that you can also take 220 volt bulbs..in a suitable base... and feed them 110 volts to increase bulb longevity in a situation where bulb replacement is difficult.

Reply to
cornytheclown

Hey thanks nothing like experience to answer the question definitively.

Regards

Reply to
steve

Much less VISIBLE light... a lot of it is downshifted to infra-red with the lower filament temperature. Might be OK if it's to be used with a security camera...?

Easier just to pay the extra $ and buy a long-life bulb (with sturdier filament) in the 1st instance.

TCM

Reply to
The Cheese Machine

Warren, something you might consider is: the extra money you spend on electricity will more than offset your savings on bulb replacements. (Of course, that doesn't address the reduced hassle of making the replacement less often, so it may be worthwhile for you after all.)

Regards,

Mark

Reply to
redbelly

=>"Reducing the voltage applied to a light bulb... snip...

Try this next Christmas.

For those of us who like to put a little electric candle in every window of the house, try inserting a diode (1N4005 reccomended) in series with the "night-light" lamp. The fool things will last forever and they will look a lot more like real candles than blinding white points of light.

In the cheap plastic affairs, the socket is usually just pressed into the upright stalk. Push it out with a long screwdriver, cut and solder in the diode to one wire (either one, any polarity), and press the socket back in place. Maybe a dab of glue to keep it from falling out later would be in order.

Oh, yeah! Unplug the light before working on it.

But you knew that, didn't you!

Cheers--

Terry--WB4FXD Edenton, NC

Reply to
Terry

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