The holidays are just around the corner, which means it"s time to find out how many light strings survived 11 months in the attic. When we find a clunker, the quest for the bad bulbs usually leads to some really creative expletives at my house.
Thank goodness Santa brought a gift early this year -- the chaps over at EDN magazine published a nifty circuit that lets you find the culprit in both series-string and alternating-series-string lights before you drive yourself crazy. Or Christmas is ruined.
Author William Dias writes:
The simple circuit allows you to divide and conquer, greatly reducing the time it takes to find the bad bulb. The circuit uses a pair of NE2 neon bulbs with current-limiting resistors.The circuit uses a pair of NE2 neon bulbs with current-limiting resistors.. It's convenient to house the tester in a clear piece of plastic tubing, with the probe tip emerging from one end and a light-duty power cord emerging from the other end. You place the bulbs in the tube such that one is close to the probe tip and the other is near the power cord, so it's easy to remember which bulb lit last." Get full instructions here.
Here's another bum light test circuit, with instructions helpfully translated from Dutch.
After you've found the bad bulbs, good luck finding replacements for them. This year, my husband wound up buying new light strings after striking out at several stores. Maybe it's a conspiracy!
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Comments (1)
Or even simpler... Use one of the FET/LED test
screwdrivers, move it along the string (no need to make contact), when the LED goes out yo have found the faulty lamp.
Posted by John Langstaff | December 19, 2007 3:06 PM