Flashing v/s Constantly ON lightbulbs

I wonder if there is an answer to this?

I was watching one of those flashing battery operated barricades they put on road construction sites. The bulbs are incandescent, similar to the bulbs used on taillights on cars. (except the new LED type).

I came up with two questions:

  1. Which consumes more electricity, a bulb that is constantly on, or flashing? (My thinking says it would be the constant on bulbs would use more electricity) ??????? [but that's just a guess]

  1. This one is much more puzzling. Will the filament last longer on a flashing light or one that is on constantly? I am looking at this in several ways. It would seem that flashing would be hard on those filaments. That flashing on and off about 40 times a minute seems like it would beat up that filament.

At the same time, the filaments never really reach full brightness long enough to develop much heat, so that could possibly make it last longer because of the decreased heat. So, this could go either way?

I'm sure someone has tested this ...... But who knows the answer? I do know that of those older C5 and C7 christmas bulbs, both the regular and the flashing ones seemed to burn out some of each every year (for whatever that's worth).

Does anyone know the answer?

Reply to
jw
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flashing uses 1/2 the battery power, and yes flashing is hard on incandescent bulbs filaments, their life is less.

nearly all new lights are LED since battery replacements costs so much

Reply to
bob haller

Lamps are rated for their service life in x-number of thousand hours... Being constantly on would consume the lamp quickly, but cycling on and off would eventually also burn it out as it does thermocycle even in the short time it gets hot compared to being off...

The lifespan of a lamp is also adversely impacted by running at higher than standard temperatures or where the lamp is subject to vibration or being jarred... Those x-number of thousand hours of life are under perfect ideal conditions...

~~ Evan

Reply to
Evan

As good of a non answer as I've ever seen.

Reply to
trader4

And you didn't even offer any sort of answer, just your opinion on what I said... Wow, you must not have anything useful to add to the subject...

~~ Evan

Reply to
Evan

For safety barricades and the like, amount of electricity consumed or length of filament life is WAY down on the list of needed features. Some above it are: brightness, dependability, immunity to rain, snow, etc., cost, and securability.

Reply to
HeyBub

A 50% duty cycle uses more than half the power used by a steady burn, becuae the resistance of a cold (non glowing) filament is significantly lower than a glowing filament - and a flashing bulb goes through that phase every time it is turned on.

As for lifespan, every time the filament heats and cools it flexes - so the flashing bulb life is SIGNIFICANTLY lower in actual on -time. At a 50% duty cycle the bulb MAY last the same time over-all - or slightly longer - or slightly less - depending on the construction of the filament and supports.

Bulbs GENERALLY blow as they are being turned on (due to that low resistance high current starting surge co-inciding with the flexing due to thermal expansion / subsidence.

Reply to
clare

I can see that as accurate, but I was referring to any incandescent bulb for any use. It's just the barricade that made me ask the question. Actually we all have taillights in cars that flash, even though they are not left on for long periods, the filament for the flasher almost always seems to burn out first on the common 1157 bulbs.

Reply to
jw

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