I was discussing using an incandescent lamp for a heater, where the amount of light is not important. I looked up some info on miniature lamps in the General Electric Miniature Lamp Catalog. Miniature lamps used to be inside of appliances, and cars, such as in the instrument panel, speedometer, glove box, etc. Now they have often been replaced by LEDs.
Did you know that the life of a miniature lamp varies inversely as the 12th power of the voltage? And the candlepower varies as the 3.6th power of the voltage. That info is from the first page, which also has a graph of these values for different voltage percentages.
I calculated that if I power the lamp with half voltage, the life will be 4096 times its rated life. So if its rated life is 1000 hours, then at half voltage it should last 4,096,000 hours. Gee, that’s 467 years! That beats LEDs by far!
My co-worker retired years ago, but she and her husband lived on the street on which I travel on the way home from work. During these winter months when it’s dark on the way home, I pass by their house and I see the street address number dimly lit from behind by an incandescent lamp. The light is probably a 28V or more lamp running from a 16V doorbell transformer. All these years, probably since the house was built, the same light bulb has been lighting that street number, the amber or orangish glow on 24/7.
This just shows how long an incandescent light will last if you’re willing to sacrifice much of the light output.
