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Old 12-09-2012, 07:58 PM
S&MLL S&MLL is offline
LawnSite Senior Member
Join Date: Feb 2008
Location: Somerset County NJ
Posts: 755
Originally Posted by steveparrott View Post
Re: humming LED's. Our tests found that some LED circuits emit an audible hum when used with an inefficient EI Laminated Type transformer. The more LED's on a line - the louder the hum, sometimes accompanied by flickering.

When you use an osciliscope to look at the current of humming LED's, you see huge voltage spikes - some of them high enough to exceed acceptable voltage limits. A humming or flickering LED is bound to fail long before its predicted life.

This is why we discontinued our 2 transformers that had EI cores and replaced them with toroids. Well-constructed toroidal transformers never produce this problem.

Funny that under generator power there was never a hum. Btw your mdl transformer hummed just as bad on this same system as any other transformer i tried
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