The Tree Lights - John Dunn, Consultant, Ambertec, P.E., P.C.

My father was an extremely intelligent man. Every week, he would fill in the entire Sunday New York Times crossword puzzle in one sitting of half an hour. That was when Will Weng was the puzzle editor and there were crossword clues like "Moldovan leader, 1929".

There were weaknesses though and we all have them, I guess.

We had never had electric lights on a Christmas tree, but one year, a neighbor offered to lend us a set.

Dad put a bulb in each socket and when he turned the lights on, they flashed brightly for just a moment and then went dark. After a while, he found that one of the bulbs had burned out, but when he put a new bulb in that socket, the same thing happened again, a bright flash and then darkness as that one bulb burned out again.

I'm afraid Dad lost it with this one. There was a box of maybe a dozen spare bulbs. He took them all, one after the other and put them in that socket only to have the flash and burn-out cycle happen over and over and over again until there were no more bulbs to try, leaving him literally panting with frustration and exhaustion.

It was not a happy scene, but just a little thought might have saved the day. Consider the following speculative and retrospective analysis.

Suppose there had been ten lights connected in a series string and just one of those lights was rated at only half the wattage of the other nine, those nine would have lit up pretty well with only 10.9 volts out of the 120 volts from the power line, but that tenth bulb would have been hit with 21.8 volts and therefore that one would have surely blown out when power was applied. (See the table below.)

 
Do you ever get so frustrated you feel like you're going to burst?

Maybe it would help to take a clue from this story and then another clue from Albert Einstein who when confronted with an intellectual impasse would say: "I will a little think."

Comments

[Jerry Meyerhoff]

Great Einstein advice. Happily there is also an affordable & available technical solution tool for the most common problem: one burned-out series light. http://www.lightkeeperpro.com/ Disclosure: a former work-place colleague is a lead engineer there & I do some new product consulting. jdm 7/31/2011