Are LED light's circuit board shielded against strong EMF and RFI?

ganymede

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As titled, does strong EMF and/or RFI has any effects on LED flashlight's onboard circuit board whether they are current limiting or PWM type?

Thanks.
 

mrlysle

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HDS systems lights are supposed to be able to survive an EMP. Hope I never have to find out if mine will!
 

DaveyJones

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wouldn't alimunium be useless due to it having no magnetic proterties?
 

mrlysle

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Have a look at the new SL series lights from Spark. They advertise EMF/RFI shielding in bold print! WTH?
 

MikeAusC

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Aluminium will not shield from Magnetic Fields, but the question was about Electromagnetic in general and Radio Frequency specifically, which are stopped by Alumium.

Aluminium is regularly used fro shielding electronic equipment.

Light is one example of Electromagnetic Field radiation.
 

PhotonWrangler

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As titled, does strong EMF and/or RFI has any effects on LED flashlight's onboard circuit board whether they are current limiting or PWM type?

Thanks.

1) Find a portable AM radio.
2) Tune it to an empty spot at the low end of the band.
3) Turn on the flashlight and hold it up to the radio's antenna.

If you hear the flashlight's PWM circuit buzzing in your radio, EMF is getting out. And if EMF can get out, it can also get in.
 

LedTed

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Thank you PhotonWrangler,

This is the best response I've read yet! :twothumbs

Sincerely,
 

AnAppleSnail

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1) Find a portable AM radio.
2) Tune it to an empty spot at the low end of the band.
3) Turn on the flashlight and hold it up to the radio's antenna.

If you hear the flashlight's PWM circuit buzzing in your radio, EMF is getting out. And if EMF can get out, it can also get in.

Depending on frequency (wavelength). I'm not an EE so I can't tell you if low-frequency (long-wavelength) EMF is a problem, but a conductive shell with holes of a given size can block EMF over a certain frequency, that frequency being based on the hole size. Now, I have no idea if that matters or if I'm just being pedantic.

I am not able to really evaluate this source, but it seems coherent and discusses EMP testing:
ECE.unm.edu

Apparently it's not really feasible to test with a nuke, which causes an EMP mainly by slamming gamma rays into the atmosphere, releasing electrons at high speed, generating a magnetic field very quickly, which pushes the Earth's field rapidly to cause damage to things. Instead we use electronics to generate an EMP, like a

In short:

EMP generation outside controlled tests are hard to predict and plan for. I see lots of people talking about testing this or that, but not much real data. Give these guys a call:

DtB Testing

Research EMP effects and physics to plan for post-EMP lighting.
 

ganymede

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Guys,

Thank you all for the great inputs, the main reason I am asking this question is because some flashlight manufacturers advertise their lights as designed to "Mil-Spec", so I am assuming a piece of equipment designed and tested to military specifications generally speaking are shielded against some EMP and RFI no?

LED flashlights are great, great runtime and super bright but if a burst of EMP or RFI can potentially fried out the circuit board are they (LED) still the preferred choice? Quoting Murphy's law here, things that can fail will fail. Keeping things simple, any assault rifles can fail but not a bayonet.
 

PhotonWrangler

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More food for thought -

One point of ingress and egress for EMI/RFI is directly through the lens, which by definition is not made of metal. While a thin coating of a conductive material can be vapor-deposited onto the lens, this will only provide very weak protection against electromagnetic fields. Anything that has a lens is vulnerable because of the lens.

As an example, many years ago I was running a video camera at a live event on an outdoor stage. It just so happened that the event was being held a half mile away from a radio station's transmitter tower. While the camera's body was very well shielded and did a great job of deflecting RFI, any time I pointed the lens in the direction of the tower I got a screenful of hash. There was no way to shield the optics from the RFI.
 

ganymede

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More food for thought -

One point of ingress and egress for EMI/RFI is directly through the lens, which by definition is not made of metal. While a thin coating of a conductive material can be vapor-deposited onto the lens, this will only provide very weak protection against electromagnetic fields. Anything that has a lens is vulnerable because of the lens.

As an example, many years ago I was running a video camera at a live event on an outdoor stage. It just so happened that the event was being held a half mile away from a radio station's transmitter tower. While the camera's body was very well shielded and did a great job of deflecting RFI, any time I pointed the lens in the direction of the tower I got a screenful of hash. There was no way to shield the optics from the RFI.

Unless you block it with a block of lead! Haha! Just kidding! :devil:
 

HooNz

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Guys,

Thank you all for the great inputs, the main reason I am asking this question is because some flashlight manufacturers advertise their lights as designed to "Mil-Spec", so I am assuming a piece of equipment designed and tested to military specifications generally speaking are shielded against some EMP and RFI no?

LED flashlights are great, great runtime and super bright but if a burst of EMP or RFI can potentially fried out the circuit board are they (LED) still the preferred choice? Quoting Murphy's law here, things that can fail will fail. Keeping things simple, any assault rifles can fail but not a bayonet.

LOL , mil-spec , i can just imagine a "opposition" parked away from a base with a Df directional antenna with a receiver that tunes from 30khz to 400khz or so listening out for those on low power or moonlight mode using PWM .

Positioning! :naughty:
 

ganymede

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LOL , mil-spec , i can just imagine a "opposition" parked away from a base with a Df directional antenna with a receiver that tunes from 30khz to 400khz or so listening out for those on low power or moonlight mode using PWM .

Positioning! :naughty:

Interesting! Did we unknowingly gave our position away to our enemies? :sssh:
 

McJagger

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Ehm... One TK11 had a problem that its led started slightly shining, very dim, when I put it onto the shelf... And it has a pretty thick body...
 
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