U2 High pitch squeal
- Thread starter hogx1
- Start date
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NickelPlate
Enlightened
- Joined
- Jan 12, 2006
- Messages
- 249
hogx1 said:
Weird,
My guess is it's the high frequency PWM for the lower levels. Evidently they're not running above the range of human hearing. Call them and let us know. Ask them what frequency their switching at at.
Regards,
Dave
greenLED
Flashaholic
Mine does on level 3 only when batts are low and I can't access higher levels. I only hear it if I put the light right next to my ear. Inductor (or some other electronic component) humming, IIRC.
PhotonWrangler
Flashaholic
Put almost any regulated flashlight near am AM radio that's tuned to an empty spot on the low end of the dial (~530-700khz) and you'll hear the oscillator quite loudly.
Works for handheld calculators also.
As long as the light isn't guaranteed to be completely silent for tactical use, I doubt that it's a problem. If it was running at a slightly higher frequency, it might annoy the dogs in your area!
Works for handheld calculators also.
As long as the light isn't guaranteed to be completely silent for tactical use, I doubt that it's a problem. If it was running at a slightly higher frequency, it might annoy the dogs in your area!
The_LED_Museum
*Retired*
I just checked my U2 quite carefully, and noted no sound on any of its six levels.
I tried holding both the tailcap & bezel against my ear to try and detect this sound.
I tried holding both the tailcap & bezel against my ear to try and detect this sound.
The_LED_Museum
*Retired*
I checked my Inova 24/7 and Gladius for squealing; I detect a faint whine from my 24/7 on low white, and no noise at all from my Gladius at any power level.
CLHC
Flashaholic
Don't have a SF.U2 but do have the SureFire L2, and it does have a slight pitch noise when activated. No problem here. Noise lets me know that it works. . .Enjoy!
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