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Old 12-31-12, 11:09 AM   #21
Lex Parsimoniae
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Originally Posted by opiesche View Post
I've recently installed some custom LED lighting. The other night I was sitting in my office during a pretty bad thunderstorm, and when lightning struck, the LED lights in my office actually came on for a second - which is very weird, because they were turned off at the switch!

There's also another fixture in the hallway, which was turned on at the time. It seems that the surge hasn't done any damage - they work just like they did before. It's possible that the transformers I use have built-in surge protection though - I've got the LED drivers built into my walls, and the light switches are just switching 12V.

The fast rise time of the lightning-jolt into an iron core transformer,
results in a high input XL (measured in ohms) which makes
the transformer a somewhat protective device.

The turned OFF lighting flashing ON during a nearby strike might have been EMP effects.
The LEDs are diodes and will convert any strong magnetic field pulse into a short burst of DC voltage.
The wires between the transformer and LEDs (and between LED elements) act like an antenna.
If you had a Ham radio guy living next door, your LEDs might be flashing every night!

The other explanation for the flash is a high voltage arc jumping past
the switch contacts and charging the primary of the transformer with
one quick jolt of power..

I like the EMP theory, since my Ham HF radio forced me to add ferrite RF blockers on my solar HW controller's sensor lines.
The high resistance of the thermistors and the long wire run up to the roof,
made that circuit a perfect HF antenna. The relays were banging like crazy
when the SSB transmitter was running.

The reason EMP generators are weapons against solid state devices (Computers & LEDs etc)
is because many of the semiconductor junctions in these devices can be badly damaged by a little too much current.
That's also the reason you need to wear a grounded static strap while working on your PC mother board..

EMP is also the reason preppers (and the DOD) build EMP shielded storage containers,
to store their emergency back-up electronic devices.

My hobby is installing & trying to repair mini-splits
EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

Last edited by Xringer; 12-31-12 at 11:21 AM..
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