strobe too fast to see?

[Snerd Mortimer]

Hi all,
Wondering if anyone has ever noticed while on low power that the light is in effect strobing too fast for the eye to see?
I was looking at a running fan pulley today at work with an Ultra Fire WF-501A w/ LED that a guy at work gave to me and the pulley was spinning herky jerky like when a vehicle wheel appears to be going backwards in a movie shot. I checked again with another LED light (Energizer Hard Case 2 AAA TUFPL22PH) and the pulley was spinning in a normal wicked fast blur.
Most peculiar...

Thanks,
Mr. Snerd.

 

[csshih]

Hi Mr. Snerd,

That is a form of dimming used lights, called "PWM"! (pulse width modulation)

some of the cheaper lights out there use lower frequency cycles, hence you can see it easier.. (one easy way to detect it, wave your hand in front of said dimmed light). some use much higher frequency cycles, which are harder to detect, or virtually undetectable.

or, some are using current based regulation, which don't cause the strobing at all.

 

[Burgess]

to Mortimer Snerd --


Welcome to CandlePowerForums !


:welcome:



BTW, i'm old enough to grasp the significance of yer' moniker.


_

 

[TooManyGizmos]

You really shouldn't call it Strobe ....

it's what csshih said ... PWM ... Pulsing.
.

 

[Juggernaut]

If your board and you find something spinning at the right frequency / RPM, take a light like the Photon Proton Pro "infinitely adjustable output" find a nice dark place take your thing "in my case an old camping fan" and after a few tries I had the PWM set up so perfectly the blades seemed to just stay perfectly in place "while spinning of course". It was interesting, by putting something behind the blades "not right up to them, just near them" I could change the air intake enough that the blades extra struggle to pull air would make the optical illusion of the blade slowly rotate one way or the other.

 

[Snerd Mortimer]

thanks all for the friendly & educational feedback .
btw, I love the Snerd moniker, I use wherever my real name isn't necessary.