What is the relationship between the life of incandescent light bulbs and voltage higher than rated voltage?

Answer 1

Sorry I don't have an equation for bulb life versus % rated voltage, maybe someone else will, but increased voltage strongly effects bulb life.

amps = voltage/ resistance

Power = volts x amps

So Power = volts x volts /resistence.

Resistence of the filament is pretty constant, so 10% more voltage makes for 21% (1.10 x 1.10) more power dissappated by the filament. i.e. it runs at a hotter temperature. And it is that hotter filament temperature that causes it to burn out sooner.

A trick for hard-to-reach bulbs is to use 130-volt rated bulbs in a 120-volt fixture. They can last many thousands of hours at the lower voltage. Doing the reverse (normal bulb operated at 130 volts) would give you a few hundred hours.

Answer 2

you've already stated that the measured resistance of your mild bulbs is plenty below the only hundred forty four ohms anticipated from the voltage and wattage score. i became wondered in the starting up after I got here across a similar aspect many years in the past. the answer to this paradox is that the resistance of the mild bulbs at low voltage has been wisely measured yet because the filament heats up, its resistance will boost, to that end by a aspect of about 16 between room and dealing temperature of about 3,000 deg ok. once you first turn on the mild, it does certainly draw a huge surge of present day that right now decreases to the operating present day after a fragment of a 2d. because of this switches often times have a separate, decrease present day score for operating incandescent lights. the answer on your difficulty is hence this: a) at nominal rated voltage, your bulb will eat the nominal rated power; the resistance measurements of the filament at room temperature do not prepare. The RMS present day can hence be computed from the equation I = P / V, for a present day of 0.eighty 3 amps. b) At 12.0 volts, the filament will expend sufficient power to warmth up heavily and carry the resistance highly yet no longer something like the aspect of 16 that takes position at complete operating voltage. the present will hence be below 12.0 V / 8.9 ? or a million.35 amps yet so a lot more desirable than the 0.083 amps you'll assume if the mild provided a similar resistance it did at complete operating voltage. My seat-of-the-pants estimate will be a present day draw contained in the selection 0.2-0.4 amps in accordance with my fairly constrained adventure with incandescents. Do do this at homestead.

Answer 3

i'm thinking that since incandescent bulbs work by routing electricity through a [tungsten] filament, attempting to carry more voltage than what's recommended will shorten the incandescent bulb's life, if not destroy it completely.

this principle is similar to the principle used in cylindrical fuses (and internet bandwidth for that matter). the amount of electricity that a wire can actually carry at any one time is directly proportional to its thickness, among other things. thus, a fuse breaks if too much electricity is made to pass through it, because the thin filament inside is designed to carry only a set amount of electricity.

thus, routing more electricity than the bulb's filament can handle should theoretically break the filament, rendering the bulb useless. keep in mind that the recommended voltage rating for bulbs is not actually the breakpoint for the filament in most cases (just an approximation with some more leeway), and it IS true that an incandescent bulb lights up brighter with more voltage over the same filament.