# List Lights that use PWM



## jon_slider (Dec 18, 2015)

*List Lights that use PWM or Constant Current that fluctuates*

If you Believe a light uses PWM (please include a photo or a link if disputed) that can be detected by waving, a camera, or oscilloscope, even if YOU dont notice it in use, feel free to add to the list. This post is not intended to discuss whether PWM is bad, good, or fast enough not to be noticed. It is ONLY about whether the circuit uses pulses.

The following lights use Pulse Width Modulation: (please add any others you know of)

Astrolux S1
Astrolux A01 Copper Old Lumens edition Nov. 2016, earlier Jan 2015 models were NoPWM
Astrolux K01 Copper
BLF D80
Convoy S2
Emisar D4
Eoslamp SP11-S
Fenix PD40 and LD05
47 mini mkII
Led Lenser NEO headlamp
Prometheus Beta Copper
Eagletac D25 (disputed) reported: here D25A Ti also here and here D25LC2 and here D25AAA, and here #65
Maratac AAA Rev 3 (PWM ended approximately with Oct 2015 batch)
Maratac AA Rev 4
Lumintop Tool AA
Jaxman E2
Klarus XT11
Liteflux LF2XT
Lumintop Tool (PWM ended approximately with Oct 2015 batch)
Lumapower LM21
HDS and another link and a pic
Jetbeam Jet-U AAA note there is a newer version that only has PWM on 10440 according to this
JetBeam RRT01 Constant Current that resemble PWM in photos
McGizmo Haiku (link shows 5 seconds of pre 2013 slow PWM on video). this post confirms the 2017 Haiku still has PWM. Here is a photo of the post 2012 faster PWM
And this one confirms the 3s revision of 2012 still uses PWM 
Malkoff MDC AA 3 mode, see photo and photo
Malkoff Wildcat
Manker LAD (Constant current with a feedback loop)
MecArmy PT60
Muyshondt Aeon Mk3
Muyshondt Beagle MKI
Nitecore Tip (disputed)
_Nitecore NU20_
Olight I3S XPL 180 lumen brass model
Olight S Mini
Olight S2a, on Moonlight #1
PflexPro dropins
Preon
Preon gen 2 series see photo
Nitecore Tube
ReyLight Pineapple pwm photo
ReyLight Ti Lan 
SGN3
Streamlight ProTac HL 3
Surefire Sidekick
Tank0007 E09
ThorFire TK4A
Thrunite TH20
Thorfire TG06S
Trustfire TR-3T6
Ultratac K18
Zebralight SC5 (controversial) selfbuilt says it has noPwm, he says same about Eagletac. Zebra scan lines in a photo, in this post #74
Zebralight SC52, pic here

Part of the PWM detection controversy is semantics. Some systems use a sort of hybrid PWM plus minimum current control, eg Eagletac, Zebralight and HDS, use pulses that dont drop all the way to zero, imo they are still pulses.. others disagree, because the strict definition of PWM is that it pulses on and then all the way off.

In my case, a light that has PWM, Pulses, Waves, Flicker, or other fluctuations, can affect my cameraphone images, so I include lights that have one of those characteristics. Make your own judgements about the interpretation, and your application for a light.

_*A note on technical definitions of PWM and Constant Current:
*_these are HYBRID drive lights that use Pulses that do not drop to Zero:_
Eagletac, HDS, Zebralight, and Nitecore Tip though they are technically NoPWM lights, they are NOT Constant Current because they use PULSES that do not drop to Zero, so cannot be called PWM by the strict definition, but ALSO cannot be called CONSTANT Current, by definition either_

#13


KeepingItLight said:


> Selfbuilt reserves the term "PWM" for drivers that rapidly cycle power between 0 and max. Modern drivers, however, such as the one found in the *BLF A6* and *BLF Kronos X6* use PWM in a more rational way. They cycle between max and a non-zero output level. On the oscilloscope this results in a ripple that selfbuilt, at least to-date, has not called PWM.
> 
> I do not know much about the *Eagletac D25A*, so I cannot say whether this has anything to do with the reports of PWM on it. I have, however, seen convincing photos posted by CPF member reppans.







Originally Posted by *reppans* 


_Selfbuilt did not test the D25A, which is all I own. The D25A only uses PWM on a couple of modes (and it's the fastest I've ever photographed), and moonlight has slow PWM-like pulsation (depending upon sample and voltage) on moonlight. 

Here are three D25A samples swept along with an HDS across a time exposure. You really can't "see" PWM this fast unless you know exactly how to look for it - I never noticed it until another reviewer pointed it out. 






And a typical D25A moonlight on low voltage vs a Quark moonlight - cellphone test and time exposure.






_#95


reppans said:


> Since we are splitting hairs, I think this old photo (a time exposure sweep) is a pretty good visual representation of the progression from "oscillation noise" to true PWM. L to R: SC52, Quark AA, D25A and MDC AA. I swept them all together, and fast as I can possibly swing my arms. Focus on the very bottom of the beam swipes.
> 
> 
> 
> ...


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## markr6 (Dec 18, 2015)

PFlexPro has some nice P60 style dropins and modded Convoy lights. These use 4500+Hz PWM.


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## Fireclaw18 (Dec 18, 2015)

Nitecore EC11, EA11


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## Thetasigma (Dec 18, 2015)

Maratac AA Rev 2 Copper on low
Maratac AA Rev 3 SS on med and low
Maratac AAA Rev 3 Copper on med and low (prior to Oct. 2015 batch)
Maratac AAA Brass on med and low
Maratac AAx2 Extreme Green and Red switchboot models
Thrunite T10T, T10S

All are easy enough to discern as PWM using a waving test, but not in normal usage conditions.

Edit: Eagletac D25A Ti, this one seems to be in question. Manufacturer claims current control on all levels, however some reviewers have found what appears to be PWM. On my particular sample the only difference I can detect is on Low with Moon off, and Med with Moon on. If they are PWM, then they are very fast as it is barely detectable.


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## Lou Minescence (Dec 18, 2015)

Nitecore EC11 - noticeable on middle modes
Olight M30 - noticeable low mode
Eagletac D25A Ti - noticeable with Nichia led not with XML2 emitter on low


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## FREI (Dec 19, 2015)

Surefire E1L with KE1 head


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## Jose Marin (Dec 19, 2015)

Nitecore p20
Foursevens preon, quark turbo 123squared


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## jon_slider (Dec 20, 2015)

*Sunny Nites Micro ATL G5 and G5 eX*


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## jdboy (Dec 20, 2015)

Malkoff MDC
NovaTac 120P (old USA version)


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## KeepingItLight (Dec 20, 2015)

BLF A6 Special Edition

Moonlight mode uses a high-frequency PWM that is around 8000-9000 Hz. Most of the other modes use PWM at twice that frequency.


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## orbital (Dec 20, 2015)

+

*Most EagleTac D25 series lights do NOT use PWM*
likely only D25A units

Personally detest PWM & I have several D25LC2s' that absolutely don't have it


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## fresh eddie fresh (Dec 21, 2015)

Malkoff Wildcat version 2-4
Icon Modus and Rogue


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## jon_slider (Dec 29, 2015)

Lumapower LM21
Zebralight SC30, H31, SC50w, SC51


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## Rutha73 (Dec 29, 2015)

I noticed it on my Streamlight Pro Tac 1AAA on low mode when I was using my drill while the power was shut off at the place I was working.


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## orbital (Dec 29, 2015)

+

From EagleTac site:

_"D25LC2 Mini runs for 100 (and up) hours on its lowest 3 lumen brightness level. The *current regulated and non-PWM* dimming circuit design allows constant and non-flashing output throughout its runtime for all output levels."

_
To say a product has a potentially negative aspect, when it doesn't, can be libel situation.

*
Good reason to close this thread.*


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## Woods Walker (Dec 29, 2015)

orbital said:


> +
> 
> From EagleTac site:
> 
> ...



Libel situation on the internet. Oh no! The OP clearly states that disputing any claims are welcome. As for closing any threads I think that's up to the mods and administrators. On a side note the old Fenix LOD has a highly visible PWM. Per my cell phone and action cam LED screen test the Fenix CL25R lantern has a PWM but totally invisible to the eye (so it really doesn't exist as seeing is all that matters IMHO). The 4/7 twisty (mini) line and preon both have PWM but not detectable during normal use and hardly much when waving around. Potential but unproven (per my tests) of PWM on the lowest moonlight modes of my ZL SC5w. I think the Inova keychain light has a visible PWM. I should check more but am only really concerned with what can actually be seen. I do think there are some pros to PWM if done right. Reduced tint shift might be one of them.


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## jon_slider (Dec 30, 2015)

orbital said:


> *close this thread.*


Open your mind, or maybe you should just ignore this thread if it upsets you too much. Your evidence is the mfg specs right?.. here is new evidence to consider:
[quote=reppans]I ran the time exposure sweep picture I mentioned before and now agree it does look like full on PWM, L > R, SC52, Quark AA, D25A, MDC AA, ~3 lms:




[/quote]

[quote=Racer]It's gratifying to see that not everyone buys the PWM-is-just-circuit-noise story. If it was just noise, then my camera couldn't see it.

Here's a video I did for the D25A mini showing PWM, which on their web site they say is constant-current. I believe what happened is that at some point EagleTac stopped using constant current circuits to get better tint, which their customers were/are complaining about. And they neglected to update all of their spec sheets--best of both worlds amirite?

[/quote]




ToyKeeper said:


> It's really easy to see PWM. Just turn the light on and wave a thin, stiff white sheet through the beam really quickly. For this purpose, I've been using a pupil distance measurement ruler from Zenni Optical. It seems almost ideal -- thinner and stiffer than a business card, long and narrow, and white.
> 
> 
> Here's what it looks like when checking PWM on my BST-wide on "low". Its PWM runs at 188 Hz (measured via sound tuner plus the audible whine it makes sometimes), at a duty cycle of 11% (measured via pixel measurements of that photo, and verified against official spec):
> ...


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## Woods Walker (Dec 30, 2015)

Is the OP planning on updating the ordinal post with additions provided or is that static. I noticed several people mentioned the Mini and it is not listed.


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## jon_slider (Dec 30, 2015)

Woods Walker said:


> Is the OP planning on updating the ordinal post



I decided not to take the time to compile, and alphabetize the post contents myself. If anyone does, the contribution is welcome.


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## jon_slider (Feb 21, 2016)

there are a few lights that use a type of circuit that some people think is a form of PWM, and others such as selfbuilt, do not consider PWM

here is an example
Zebralight SC5 (controversial) selfbuilt says it has noPwm

similar reporting/measuring differences of opinion about the definition of the word PWM occur when discussing the Eagletac

for example, selfbuilt seems to follow the strict definition of PWM defined as a pulse that turns completely off between pulses, so by that definition, a circuit with a pulse that never goes fully off, is not PWM.. however, it IS a Pulse.

for me, the definition of PWM means PULSED, regardless of whether the pulse goes fast, slow, high, or low, a pulse is a pulse, to me, my brain, and my iPhone camera

note, Im not trying to argue whether the PWM matters, is undetectable, gives headaches, etc,, Im just reporting lights that use PULSED circuits, commonly known as PWM.

so, imo maukka 
"PWM is used to control output on all modes except H1. The PWM is not visible to the eye, because of its low amplitude, but possibly shows up on camera. The cycling frequency is higher on higher output modes and ranges from 775 Hz to 5000 Hz. The amplitude however is higher on the higher modes."
is correctly reporting PWM in the SC5, and selfbuilt is not, due to a difference in terminology, semantics and definition.. 

I think we can all agree though, that the SC5 circuit is PULSED in a way that never drops to zero, what I might call clipped PWM. There are pulses, and current drops, but not to fully off between pulses, its more like dimming down and dimming up, than just on off on off...

fwiw, I believe the Haiku and the Eagletac also use this type of clipped pulse.

note, Ive been including links any time I add a new light that I believe belongs on the list, so people can form their own opinion based on reference info. I invite others to do the same, so we can discuss any of the information available, without venturing purely opinion.. sources may vary, but please, post sources and references if you can.


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## jon_slider (Mar 13, 2016)

Added a new one to page 1: Liteflux LF2XT
The more I add the more it seems the vast majority of lights people use are PWM based.


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## amanichen (Mar 13, 2016)

jon_slider said:


> there are a few lights that use a type of circuit that some people think is a form of PWM, and others such as selfbuilt, do not consider PWM
> 
> here is an example
> Zebralight SC5 (controversial) selfbuilt says it has noPwm
> ...



I think a lot of this is the normal ripple from a boost circuit, which does use an internal switching frequency to function. You'll see a triangle like wave:
https://en.m.wikipedia.org/wiki/Boost_converter#


PWM waveform goes flat to zero as seen here: http://www.flashlightreviews.ca/BC40.htm


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## jon_slider (Mar 13, 2016)

amanichen said:


> PWM waveform goes flat to zero as seen here: http://www.flashlightreviews.ca/BC40.htm



thanks for the links, here is the PWM picture for the Jetbeam you linked to (much respect for offering links)








amanichen said:


> I think a lot of this is the normal ripple from a boost circuit


I dont think maukka is talking about boost circuit ripple, here is his post and picture*
PWM is used to control output on all modes except H1.
*





Those two plots show pulses. I agree with you that "technically" PWM drops to zero, which is why I understand that selfbuilt calls the pulses of the Zebralight SC5 "not PWM".

Its a difference in definition. If I ask does the Zebralight have pulses that drop to zero, then the answer is No. If I ask if it has Pulses, the answer is Yes.. thats why I call it "controversial"

thanks for your thoughts


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## HB 88 (Mar 13, 2016)

My favorite lights, the NiteCore Smart PD series utilize PWM. Both AA and CR123 versions.


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## Tre_Asay (Mar 13, 2016)

So far I have seen pwm on a thrunite t10 (nearly dead battery on low), Zebralight sc52fw, and h502c l2
(with nearly dead battery). I believe that I do have media showing all of them.


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## amanichen (Mar 14, 2016)

jon_slider said:


> thanks for the links, here is the PWM picture for the Jetbeam you linked to (much respect for offering links)
> 
> 
> 
> ...



Just because there are "pulses" does not mean that there is PWM in the circuit. I looked at all of the photos in maukkas post and none of them actually look like PWM - they all look triangular without the characteristic squared off shape of PWM.

Where is the PWM?


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## maukka (Mar 14, 2016)

It's not pwm. Bad choice of words.


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## SemiMan (Mar 14, 2016)

The strict definition of PWM is the Width of the pulse is modulated. There are many other methods to implemented pulsing and brightness control that are not PWM. PDM, PAM, DSM ....


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## SemiMan (Mar 14, 2016)

jon_slider said:


> PWM is used to control output on all modes except H1.
> [/B]



This plot is AC coupled so we don't know where the real bottom is.


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## maukka (Mar 14, 2016)

SemiMan said:


> This plot is AC coupled so we don't know where the real bottom is.


Here's the dc coupled one with the horizontal center line as zero output.






And as I said in the review, it is not visible to the naked eye at all.

Here's Jaxman E2 which exhibits a higher change in output although at a high switching frequency too. This is visible if you know what to look for.


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## jon_slider (Mar 14, 2016)

thank you all for joining in and adding to the discussion

so, its not PWM if the wave is not square and drops to zero, but it is pulsed if an oscilloscope shows wave?

I am getting closer to understanding why my photos have scan lines in them with some lights and not with others. I thought the scan lines were caused by PWM, now Im wondering if the waves seen on the scope would do the same?

I was interested in the SC5 until I took the above info from maukka to mean the SC5 would show scan lines if I used it to take photos.

What is correct, will the SC5 with the wavy line displayed above, affect my iPhone photos?

Can we speak to the effect of the wavy line on photography, even if the wavy line is not called PWM, can we agree it shows PULSES?

much appreciate the education..

I would like to learn which lights do not have ANY pulses that affect my photos. Even if the PULSES are not square waves as in the strict definition of PWM. Suggestions and links I can get more education from, most appreciated.


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## SemiMan (Mar 14, 2016)

Could be PWM into a capacitor on the output which I would expect at those frequencies (5Khz).

Both traces illustrated appear to have the same 200uSec period. They do not appear to be different frequencies.

Of course it could just be a peak mode current controller, but unlikely in the size of a flashlight and that low a frequency.


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## jon_slider (Mar 14, 2016)

SemiMan said:


> Could be PWM into a capacitor on the output which I would expect at those frequencies (5Khz).
> 
> Both traces illustrated appear to have the same 200uSec period. They do not appear to be different frequencies.
> 
> Of course it could just be a peak mode current controller, but unlikely in the size of a flashlight and that low a frequency.



Thanks for your posts. Honestly, I dont understand them, well enough to know whether the SC5 will create scan lines in a photo.

If I read you right, whether its called PWM or not, the scope shows pulses. Is this correct?



SemiMan said:


> The strict definition of PWM is the Width of the pulse is modulated. There are many other methods to implemented pulsing and brightness control that are not PWM. PDM, PAM, DSM ....



Im less concerned about the technical details about how the power is processed, be that through a capacitor, or a peak controller, or other pulse control technology.. Im really just asking if the light PULSES?

the Jaxman example adds to my confusion, since some people say it uses PWM, and the present discussion suggests it PULSES, but not by using PWM.. 

help, Im drowning in alphabet soup!


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## bykfixer (Mar 14, 2016)

^^ well you asked.


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## maukka (Mar 14, 2016)

jon_slider said:


> I was interested in the SC5 until I took the above info from maukka to mean the SC5 would show scan lines if I used it to take photos.
> 
> What is correct, will the SC5 with the wavy line displayed above, affect my iPhone photos?



Any light that exhibits some sort of pulsing will cause artifacts in photos/videos if the switching frequency of the light and the shutter speed or electronic update rate of the sensor happen to match in some particular way. SC5 will also cause problems with photo and videography. The amplitude of the pulsing doesn't have to be very high for this to happen. I would only use lights with totally flat output for this kind of work.


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## SemiMan (Mar 14, 2016)

jon_slider said:


> Thanks for your posts. Honestly, I dont understand them, well enough to know whether the SC5 will create scan lines in a photo.
> 
> If I read you right, whether its called PWM or not, the scope shows pulses. Is this correct?
> 
> ...




Well you can see it on the scope, the light output does change w.r.t. time. Visually you will never see it. With a cell phone camera, yes you will likely be able to detect it, though depending on the cell phone camera, it may be subtle. On an DSLR, low shutter speed, perhaps not.

It would not be accurate to say the light has "pulses", but the light does have flicker. It has flicker at about 5KHz.


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## jon_slider (Mar 14, 2016)

maukka said:


> Any light that exhibits some sort of pulsing will cause artifacts in photos/videos if the switching frequency of the light and the shutter speed or electronic update rate of the sensor happen to match in some particular way. SC5 will also cause problems with photo and videography. The amplitude of the pulsing doesn't have to be very high for this to happen. I would only use lights with totally flat output for this kind of work.



Thank you. I will then take the liberty of keeping the SC5 on the list of Lights with PWM, with the disclaimer about the technical distinction about the manner in which the Pulses are delivered.



SemiMan said:


> Well you can see it on the scope, the light output does change w.r.t. time. Visually you will never see it. With a cell phone camera, yes you will likely be able to detect it, though depending on the cell phone camera, it may be subtle. On an DSLR, low shutter speed, perhaps not.
> 
> It would not be accurate to say the light has "pulses", but the light does have flicker. It has flicker at about 5KHz.



ok, getting closer.. no pulses yes flicker? its pulse width modulation but otherwise its not a pulse its a wave, and a wave is a flicker.. I will think more deeply on this

Meanwhile would it be fair to say the SC5 does not have PWM it has Flicker, in a way that can disrupt a camera phone? am I close?

and thanks to all of you
this thread has taught me that I dont need to fear just PWM, but in addition I need to avoid Flicker and Pulses, in regards to photos I take of my lights with my phone anyway..
much appreciate the education on the correct use of terminology


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## jon_slider (Mar 26, 2016)

Maratac AA with PWM
https://youtu.be/2jL7TiIQ4yM?t=4m39s


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## jon_slider (Apr 16, 2016)

added Lumapower LM21 to the YesPWM list in the first post


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## neutralwhite (Jul 11, 2016)

Is 4500+ pwm safe?.
Is that low?.
thanks.




markr6 said:


> PFlexPro has some nice P60 style dropins and modded Convoy lights. These use 4500+Hz PWM.


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## jon_slider (Jul 12, 2016)

neutralwhite said:


> Is 4500+ pwm safe?.
> Is that low?.
> thanks.



I dont know if it is "safe", some people dont care about PWM. It is not Low.

If you can please add a link to the light you are talking about that uses PWM.


Ive just started learning about PWM frequencies, here are the values, with links to the sources, that I know so far.

Malkoff PWM frequency is *310* Hertz

Zebralight ranges from *775* Hz to 5000 Hz.

Maratac lights use visible *200Hz* PWM on their Medium/Low levels.

I have only owned the Maratac, Prometheus Beta, and Lumintop Tool that all had PWM. I dont know the speeds of the Beta and Tool. They all showed on my photos, and were all made by Lumintop. The newer Maratacs and Tools since end of 2015 no longer use PWM.

for me personally, NoPwm is good PWM. I dont want PWM at any speed. I save tons of money with that criteria, I also miss out on some very popular lights


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## jon_slider (Aug 18, 2016)

added another PWM light to the first post
Nitecore TIP






now removed because Nitecore updated the info


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## maukka (Aug 18, 2016)

BLF D80 has a bad case of PWM.


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## jon_slider (Oct 31, 2016)

added Maratac AA Rev 4


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## Lexel (Oct 31, 2016)

All Convoy lights with 7135 drivers use 4500Hz PWM


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## jon_slider (Nov 1, 2016)

Lexel said:


> 7135 drivers use 4500Hz PWM


outstanding photo, thanks for the info!


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## GODOFWAR (Nov 1, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Does the pwm effect the flashlight life?


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## BugoutBoys (Nov 1, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Nitecore P10
Nitecore TM03


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## harro (Nov 1, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

I really like my big old Xtar S1. Its a tough, knockabout light, that does a good job of most anything asked of it. Whilst max appears to not have any pwm, the variable lower outputs have very noticible pwm. The lower the output, the worse it appears. It can appear to nearly ' stop ' the blades of an operating room fan. No scopes or measurements here, just what my eyes see. Feel free to comment.


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## GODOFWAR (Nov 1, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Please tell me if the PWM will cause any problems of any kind in future I ordered many Zebralight SC5 & sc52 please let me know


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## harro (Nov 1, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*



GODOFWAR said:


> Please tell me if the PWM will cause any problems of any kind in future I ordered many Zebralight SC5 & sc52 please let me know



To many people, slower PWM can appear like a really superfast strobe, without an actual off period, some of the faster PWM may not even be detectable by the human eye. Its not necessarily a bad thing for all that. A lot of us own lights that do use PWM to control outputs of lower levels. These days, you'd be pretty hard pressed to detect whether or not a light uses PWM with your eye. It was a more noticible phenomena early on with a lot of the good brands. These days, not so much. I dont know about Zebralight, but if they do use it, i would hazard a guess that it would be of sufficiently high hz, that you would only detect it with a scope, not by eye. I'd say, buy your Z/L, and enjoy it, they are a mighty fine light.


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## jon_slider (Nov 2, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*



amanichen said:


> Just because there are "pulses" does not mean that there is PWM in the circuit. I looked at all of the photos in maukkas post and none of them actually look like PWM - they all look triangular without the characteristic squared off shape of PWM.
> 
> Where is the PWM?



Where is the Constant Current?

I agree that not all pulses are PWM, however lights with pulses are also not Constant Current.

added Tip to lights with YES PWM because it is NOT a CONSTANT Current light

fwiw, discussion of the pros and cons of PWM, whether it matters to someone, is not the goal of this thread. I just want to list lights that use PWM. If someone wants to learn more, and discuss the pros and cons, maybe read, and then post to the PWM sticky at the top of the page.


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## jon_slider (Nov 16, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*



GODOFWAR said:


> Thrunite Tn4A!


is this a mispost?
if you disagree with selbuilt, please post photo evidence of PWM

selbuilt says:*TN4A PWM/Strobe

There is no sign of PWM that I can see, at any output level – the TN4A is fully current-controlled.*


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## iamlucky13 (Nov 16, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

* EDIT - Context relative to a removed post I originally responded to: a poster was concerned that a light measured with an oscilloscope as not being PWM controlled seemed to him to show signs of PWM during a specific test. *

1.) It's worthwhile for those who want to gain a detailed understanding on this topic to recognize there is a difference between PWM duty cycle only, open-loop regulation and PWM used with smoothing and feedback in current control, and why the latter can be detected in some PWM tests.

2.) A DC offset ripple in a light that uses PWM as part of a current control method is usually far less of a concern than PWM duty cycle only, open loop regulation. One term used for this is switched mode output ripple.

3.) Most importantly of all, we should understand PWM is generally avoided (a) if it causes flicker that is noticeable in real use situations and (b) if it results in inferior brightness regulation or efficiency, since the simplest designs have to be paired with a current-limiting resistor and can be very highly affected by battery voltage.

# 3 is really what it's all about: having a light that is not distracting or obnoxious, and shows good regulation and runtimes.


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## dc38 (Nov 17, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Lets add the preon gen 2 series.


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## chillinn (Nov 18, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*



iamlucky13 said:


> ...is really what it's all about: having a light that is not distracting or obnoxious, and shows good regulation and runtimes.



Why can't it be all about having a smooth high-quality output with fantastic runtimes and perfect regulation? Merely not being distracting or obnoxious is really sort of phoning it in from a designer's stand point. I hope they can do better than that.


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## jon_slider (Nov 18, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

gentlemen, this thread will get out of control if we dont focus on the title.. LIST LIGHTS…
it really is not a thread about WHY lights have PWM, or not, how bad the PWM is, or whether someone cares about the PWM.. as that can of worms is full of different opinions

all I ask is if you think a light belongs on the list, name it, and provide a link or a photo that gives evidence, a photo proving the PWM

I suggest that more detailed discussion of the pros and cons and technical differences in NON Constant Current lights, would be appropriate to discuss in the PWM sticky.. And out of courtesy to that thread, read it first, so we dont have to answer the same questions over and over..

no offense to anyone or their opinions and contributions.. Im just trying to stay focused on listing the lights… something even I have trouble doing.. as you can see by this post 

whirled peas


----------



## bykfixer (Nov 18, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

^^ Thank you!!! Well put.

It seems like Streamlight is moving away from PWM in some of their popular lights. I did notice the low setting in the ProTac HL4 had 1 line showing in my slow shutter speed vs fan blade trick that typically picks up PWM. To go from 2200 to 600 lumens it's either really, really, really fast or current controled. But like I said at 60 lumens one line showed up each time I took a photo at 1/2 second vs a rapidly moving fan blade.


----------



## Woods Walker (Nov 18, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Some time ago (maybe) I had a debate with perhaps (memory is fuzzy) the OP over if the ZL SC5w had PWM or not. I strongly thought it didn't but got a different point of view. Did we ever determine if the SC5w has PWM. I don't see it so still think it doesn't but then again there are lights with PWM beyond my ability to see.


----------



## jon_slider (Nov 19, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*



Woods Walker said:


> Did we ever determine if the SC5w has PWM.


I have not yet seen any photographic evidence of PWM, nor of Constant Current for Zebras.
I HAVE seen photos of oscilloscope pulses for Zebralight. Please read all posts in this thread and also in the thread linked below:

I solicited photos in this post (but none have been posted yet), in the Lights with NoPWM thread:
#45


jon_slider said:


> Suggested PWM/pulsed/ Non Constant Current Perceptibility tests that can be photographed:
> 
> 1. it's visible on the scope as x% pulses
> 2. Lines visible in photographs of close up beam shots, or close ups of the led turned on.
> ...



If you can, please try to do tests #2,3,4 and post photos of the results

until I see photos, the only thing I think I can say is that Zebralight does not use Pure PWM, and also does not use Pure Constant Current. Zebras use high frequency pulses that do not drop to zero.

Im hoping that photos will reveal whether the Zebralight pulses are visible to a camera, and not just to an oscilloscope.


----------



## Trango (Dec 7, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

@ jon_slider

Led Lenser NEO headlamp on low has PWM


Picture
1/13s ; f/1,8 ; ISO 1600


----------



## swan (Dec 7, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

I have an Olight I3S XPL 180 lumen brass model.

On high medium and low it has no detectable PWM but on the timed 3min stepdown it lowers to 90 lumens this is where it displays a very visible annoying pwm flicker.


----------



## jon_slider (Dec 8, 2016)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

thank you Trango and swan, Ive added your lights to the first post, with links to your comments. Please add photos if possible. Happy Holidays!


----------



## jon_slider (Jan 20, 2017)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

About Manker LAD PWM
I cannot detect dots when waving the light really fast.
I cannot detect scan lines in closeups of the beamshots.
There IS some kind of PWM interference on extreme closeup, both still photo and video:






by contrast here is the extreme closeup of a Lumintop Worm w Nichia




and Worm video


----------



## jon_slider (Jan 27, 2017)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

EagleTac D25C Ti 2017 w Nichia 219B 5700k LED, taken with Samsung Galaxy S3 Mini, photo and video courtesy of Dr. Forinor



still photo





also added ReyLight Ti Lan
#1


gunga said:


> The middle and high modes still use PWM


----------



## wle (Feb 17, 2017)

XTAR WK42


----------



## jon_slider (Feb 19, 2017)

wle said:


> XTAR WK42


thanks, can you include a photo of the PWM please?
I do see someone else also reported PWM on that light, here


----------



## maukka (Feb 20, 2017)

MecArmy PT60


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## jon_slider (Feb 20, 2017)

maukka said:


> MecArmy PT60


thank you maukka, your reviews provide the most complete info about a light that I could hope for.


----------



## jon_slider (Apr 10, 2017)

added Olight S2a to first post


maukka said:


> PWM is not used, but there is some high frequency switching on the moonlight mode on the S2A. The flickering is noticeable only by video cameras or by moving the light fast


----------



## Woods Walker (Apr 10, 2017)

Ok I tested the XP-L V3 NW Viking. No PWM on any mode. The same applies to the XP-L V3 standard wizard. However the XHP-50 V3 Pro wizard has a UI bug which make a single flash or pulse which matches the side green switch indicator light on medium mode only. You have to what till the green indicator light on medium mode flashes to see it. The camera picked it up and I think the issue was discussed in my review though will include photos as now have them. A single pulse and it was hard to time the camera to catch it. Must have taken 20 photos to get the tail end of one as it's a single blip and there is a kinda big lag of uninterrupted light between. Will include photos later. Also there is this....

Nitecore NU20. Low....





Medium......





I totally can not detect this any other way aka no amount of shaking or rain (ran in the rain for 8 miles with it) can see it but still despite that the cellphone camera sees something and the manufacture says is CC. This was also put in my review. I will put the photos of the XHP-50 up in a day or so for evaluation. Working on a few threads for CPF tonight.


----------



## jon_slider (Apr 11, 2017)

Woods Walker said:


> Nitecore NU20.
> 
> Medium......
> 
> ...



outstanding photo! added a link from the first post to yours..


----------



## jon_slider (Apr 12, 2017)

added Jetbeam Jet-U AAA note there is a newer version that only has PWM on 10440 according to this


----------



## jon_slider (Apr 15, 2017)

update regarding Zebralight and my expanded understanding of the term Constant Current (which until now, I used the term incorrectly, to mean the opposite of PWM)

It is possible to have constant current that shows noise in a photo, which is not PWM technically, but the LED is not constantly on at constant brightness. I will continue to include Zebralight in this thread, because their system causes interference in a photo

#59


Lex Icon said:


> AFAIK…there are two basic types of regulation, since there are two basic categories of drivers; constant-voltage and constant-current. Either basic class of driver, CC or CV might employ PWM to control lumen output.
> 
> CV drivers provide flexibility up to the maximum power rating, and are available in low-voltage outputs through the use current-limiting resistors to protect LEDs from voltage variations. Normal deviations from as little as 3.3 to 3.5V, can go way beyond doubling the maximum current rating of an emitter, which then can become very bright and too hot (Poof).
> *Constant-current regulators are replacing current limiting resistors, but use feedback-monitoring circuitry to enhance efficiency, and incorporate current balancing protection, sometimes manifesting as pulsing that can resemble PWM.
> ...



this is a Zebralight SC52 LED closeup:





Here is another light that uses a form of Constant Current that is not Constant Brightness, and also causes photo interference, Manker Lad:


----------



## ligerpaw (Apr 18, 2017)

We prefer PWM as the voltage output is stable, but the frequency of the PWM neeｄ to be high above 20Khz, as 20-20Khz is sensltive for Human hearing.


----------



## jon_slider (May 10, 2017)

added Astrolux K01 Copper



Lexel said:


> The light has PWM in moon and medium/high mode


----------



## maukka (May 10, 2017)

ThorFire TK4A, PWM at 20.9 kHz on all modes except turbo.


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## jon_slider (May 10, 2017)

maukka said:


> ThorFire TK4A, PWM at 20.9 kHz on all modes except turbo.



thanks! from your link:


----------



## LeanBurn (May 10, 2017)

deleted post


----------



## maukka (May 12, 2017)

Just an update on Zebralights since I got my faster sensor.

It's not PWM as discussed previously, but don't be surprised if you see flickering on camera.

I don't remember the exact modes these were measured from, but it is similar on some L and M modes. The frequency changes depending on the mode.

In all the pictures horizontal center line is zero output. So it's more than just a very low amplitude flicker especially on the SC5Fc.

H600Fd





SC600w Mk3 HI





SC5Fc


----------



## jon_slider (May 12, 2017)

maukka said:


> it's more than just a very low amplitude flicker especially on the SC5Fc.
> 
> SC5Fc



Thanks for the pics!

educate me on duty cycle please. It shows 31%
what does that mean. Is it at max brightness just 31% of the time, and or does it drop 31% below max brightness, or something else?

Is the duty cycle just the feedback loop in the constant current power management, or is there something else going on?

seem like this duty cycle factor might account for the long run times Zebras achieve. 

here is a pure PWM plot you did of the S1R moonlight, the duty cycle is 58%, higher than the Zebra, it just sits on the midline instead of above it. (pic links to your post)


maukka said:


>


----------



## maukka (May 12, 2017)

jon_slider said:


> educate me on duty cycle please. It shows 31%
> what does that mean. Is it at max brightness just 31% of the time, and or does it drop 31% below max brightness, or something else?



Duty cycle is the ratio of the pulse's width to the cycle period. I.e. 50% duty cycle means the light is on half the time. On sloping signals it is not clear how my scope calculates it but judging from the pictures I suppose it considers a signal above 50% of the amplitude to be "on".

In PWM you increase the brightness of the light by increasing the time the LED is on = higher duty cycle. Lower duty cycle is easier to see as flickering.



> here is a pure PWM plot you did of the S1R moonlight, the duty cycle is 58%, higher than the Zebra, it just sits on the midline instead of above it. (pic links to your post)



That measurement has been zoomed in on the trace and does not represent how the output is behaving. The center line is not zero output. This is revealed by the "Coupling AC" on the image.

Duty cycle is pretty much meaningless if true PWM is not used. i.e. the output drops to zero between pulses.

Here are the new measurements for the Olight S1R measured on DC coupling = center line is zero output. There's pulsing on the output on moonlight, low and mid. Flat at high, turbo and turbo s. I wouldn't still call that PWM, just (switching) noise. Nevertheless, it may show on photos and videos.

Moon





Low





Mid


----------



## maukka (May 12, 2017)

Here are couple extreme examples where the duty cycle is under 1% and the flickering is very easy to see.

MecArmy PT60 on low





BLF D80 on low





Here's the D80 on mid. You can see that the frequency stays the same (186 Hz), but the pulse is now on for longer. Still very easy to notice because of the low frequency.


----------



## jon_slider (May 15, 2017)

Here is a photo, thanks to maukka, that overlays a theoretical PWM square wave over the Zebralight SC5fc pulsed power management system





since the Zebralight pulses don't drop to zero, they are technically not true PWM, but, the Zebra is dropping to within 18% of zero.. That probably explains the long runtimes Zebras get, and technically they use Constant Current, but with a feedback loop that causes large fluctuations in power and brightness, albeit at very high speeds. Imo the Zebra definitely belongs in this List of lights with PWM or Pulsed circuitry.


----------



## SoCalTiger (May 15, 2017)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Add Thorfire TG06S to list.

Thorfire TK4A PWM is roughly 21 kHz. (Sofirn SF11 is also a clone of TK4A and I believe Sofirn is an OEM for Thorfire).

EDIT: I apologize on jumping this so quickly. I'll work on grabbing pictures of the PWM.


----------



## SoCalTiger (May 17, 2017)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Thorfire TG06S PWM captured on Low:


----------



## jon_slider (May 17, 2017)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*



SoCalTiger said:


> Thorfire TG06S PWM


added and linked to your photo
thank you, very helpful


----------



## jon_slider (Jun 30, 2017)

*Re: List Lights that use PWM or other forms of Flicker or Pulsing*

Here is a light that uses current regulation, and also has visible flicker, the Muyshondt Aeon Mk3





#6


PoliceScannerMan said:


> I am a little bummed this thing uses PWM but its not too noticeable, wish the low was a little lower but other than that I am a happy camper.




Originally Posted by *jon_slider* 


_the Mk3 Aeon web info says:fully regulated output current
_


PoliceScannerMan said:


> It is definitely PWM I don't notice flicker on my regulated lights.



there are a number of lights that use regulated current, but still flicker, or have "circuit noise", including Zebralight, Eagletac, Tip, LAD, and others. Though technically not pure PWM, they do cause interference that can be detected in a photo. Some, like the Muyshondt, can also cause visible flicker.

#23


ShineOnYouCrazyDiamond said:


> Aeon MkIII... visually disturbing amount of PWM on the medium level.


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## Ozythemandias (Jun 30, 2017)

Guess the Muyshondt Beagle MKI should be added to this, unless you want to wait for the production version to confirm. Seems to only have PWM on mode 4:


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## jon_slider (Jun 30, 2017)

Ozythemandias said:


> Muyshondt Beagle MKI


added, thanks

weird that the Beagle webpage says 
"fully regulated"
yet you can see and photograph flicker


----------



## Modernflame (Jun 30, 2017)

I've seen other Streamlight models in this thread, but this is the ProTac HL 3. Pulse width modulation fo sho.


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## jon_slider (Jun 30, 2017)

Modernflame said:


>


thanks, added to page 1 also
what is happening in the pic, is that a wall shot or what?


----------



## Modernflame (Jul 1, 2017)

jon_slider said:


> thanks, added to page 1 also
> what is happening in the pic, is that a wall shot or what?



That is actually my shower curtain, which is flat and smooth. The striations are a property of the light. I took several photos of the curtain while waving the light around on low beam. Oh, and the image has been rotated 90 degrees counter clockwise. Should make more sense now.


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## jon_slider (Oct 26, 2017)

Zebralight SC 52 XML2 with 1/8 minus green Lee Filter (top beam). This is not true PWM because the pulses don't drop to full zero. Zebralight uses Constant Current with a feedback loop that pulses the LED in a way most users without a scope or camera usually don't notice.


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## ank (Oct 27, 2017)

I also made a few tests with my phone camera on all flashlights that I current own and these are the results:
Fenix PD35 TAC - no pwm
Lumintop tool AAA Nichia - no pwm
Acebeam K70 - no pwm
Emisar D4 - has pwm
Thrunite Ti3 AAA - no pwm


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## jon_slider (Oct 27, 2017)

ank said:


> I also made a few tests with my phone camera on all flashlights that I current own and these are the results:
> Fenix PD35 TAC - no pwm
> Lumintop tool AAA Nichia - no pwm
> Acebeam K70 - no pwm
> ...



Thank You
Yes the D4 is a light that uses FET and PWM, if you have a photo of the PWM I would be glad to add it to this thread
I agree the Lumintop Tool (made after oct/2015), has NoPWM, same is true for Maratac AAA
I also agree the Ti3 AAA is a NoPWM light.
Fenix and Acebeam I have no info on other than your report, and if you provide photos, I will add them to the first page as well.

Thanks for taking the time to share info, have a great weekend!


----------



## ank (Oct 27, 2017)

Emisar D4, first picture more obvious:














Fenix PD35 on low





on high:






I forgot this one - Convoy S2 UV light, no PWM


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## jon_slider (Oct 27, 2017)

thank you ank
added the D4 to the first page with a link to your excellent photo 

there is a separate thread for lights wNoPWM, so I added the Fenix and Convoy UV there, with links to your pics also


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## jon_slider (Oct 28, 2017)

Like the Maratac AA, the Lumintop Tool AA has PWM also:
http://budgetlightforum.com/comment/1211678#comment-1211678


MascaratumB said:


>


----------



## spydie fanatic (Oct 29, 2017)

I have 3 klarus xt11...an original olive drab and two black...both the black have no visual on 123s, but on 18650 has quite noticeable levels on medium and low modes it drives me nuts using anything but hi mode. Have a xt15 and xt12gt x2 and nothing I can detect with my eyes.


----------



## jon_slider (Oct 30, 2017)

spydie fanatic said:


> klarus xt11



thank you, added to first page, 
selfbuilt also reports the Klarus xt11 uses PWM, here


----------



## jon_slider (Nov 9, 2017)

A photo of the faster PWM on McGizmo Haiku after 2012 from this thread






and some info about PWM inefficiency:

"PWM isn't good even if you can't see or hear it"


----------



## Beard Man (Nov 9, 2017)

Tere is PWM from McGizmo Haiku which I received a couple weeks ago,
no PWM on High mode.

 - Haiku XP-G2 3S
- 4500 CCT
- 3 modes: L,M,H

The PWM is super fast and I can't see it when using my light on any level.

The light just awesome,the beam profile even better


----------



## jon_slider (Nov 9, 2017)

Thank you for the photos.
That does look like superfast PWM.
And I believe you when you say you can’t see it in actual use.
All good things.

One of the benefits of PWM is that it produces constant color or consistent tint.
Congratulations on your beautiful Haiku!

FWIW, an example of different speeds of PWM:
Quote is from here


“reppans said:


> A close-up pix (close enough so it fills the frame and can't quite focus) of the emitter with a smartphone is a pretty reliable test.. here's an example of a current regulated, high freq PWM, and low freq PWM light



The example of fast PWM looks similar to the constant current feedback on zebralights.
Some people are affected by this type of fluctuation when they use the light as ambient source for long periods. 

It is almost impossible to detect zebralight constant current flicker by waving the light. And most people say they do not notice in actual use, even though it can be captured in a photograph.


----------



## rookiedaddy (Nov 9, 2017)

hmm... no Fenix on the list? let me contribute... 

@jon, how do we classify a light that do PWM-like only on specific occasion?

The flashlight, Fenix PD40:





Fenix PD40, Eco mode:





and again, Fenix PD40, Eco mode:





taken from the LED end:






and another Fenix, an old Fenix LD05, really really really, seriously, really really really bad PWM!





Fenix LD05, Low mode:





taken from the LED end in Low mode:






Fenix LD05, Med mode:





taken from the LED end in Med mode:







now, back to Fenix PD40. how to get that PWM-like wave line? well, if you have a unit of PD40, do the following:
Step 1: Turn on your Fenix PD40
Step 2: Switch the mode on your Fenix PD40 to Eco mode (20 lumens)
Step 3: Turn off your Fenix PD40
Step 4: Turn on your Fenix PD40
Step 5: Now, wave or swing the Fenix PD40 like a crazily insane flashaholic with the lovely neutral white MT-G2 LED pointing at your own face... Voilà! instance PWM!

and to get-rid of that Fenix PD40 PWM:
Step 1: Turn on your Fenix PD40 (if it's off and/or your last memory mode is not Eco, 20 lumens mode)
Step 2: Cycle the mode to Eco mode
Step 3: Now, again wave or swing the Fenix PD40 like a insanely crazy flashaholic with the sweet neutral white MT-G2 LED pointing at your own face... hmm... no PWM!

:laughing:


----------



## Beard Man (Nov 9, 2017)

jon_slider said:


> Congratulations on your beautiful Haiku!



Thank you Jon!


----------



## jon_slider (Nov 10, 2017)

I don’t know a lot about PWM or Constant Current speeds, and have no scope. Here are a few collected photos, for sake of comparison.

One thought might be to count how many bars overlay the LED, to get a rough idea of relative speeds.

These photos all come from different people. The Manker photo is from my iPhone 5. It is surprisingly similar to the Zebra, and both are Constant Current lights.. btw, the manker CCFlicker cannot be seen by waving the light like a mad flashoholic. or in "normal" use. I only found it by extreme Closeup of the LED. I cannot hear any inductor whine, when holding the manker to my ear.











Beard Man said:


> PWM from McGizmo Haiku
> ...
> 
> 
> ...


----------



## LogicalBeard (Nov 12, 2017)

With the Beagle they said it was circuit noise that was only present in the prototypes. Who knows if that is true. I don't see any PWM in my Beagle: Which isn't a prototype. And nobody in the FB group has mentioned seeing it. I could try and do some checks for it for you guys. What's the best way to try and get it to be noticable?


----------



## jon_slider (Nov 12, 2017)

LogicalBeard said:


> What's the best way to try and get it to be noticable?



see post 104


----------



## jon_slider (Nov 24, 2017)

interesting photo of multiple overlapping HDS power pulses

http://www.candlepowerforums.com/vb...stems-EDC-19&p=5155771&viewfull=1#post5155771


Tejasandre said:


> HDS...


----------



## neutralwhite (Dec 16, 2017)

Is this PWM rate acceptable ?. 


" On the driver well it is PWM on the levels but not high as there is no reason for it to be on high. They are 5KHz "


----------



## ssanasisredna (Dec 16, 2017)

neutralwhite said:


> Is this PWM rate acceptable ?.
> 
> 
> " On the driver well it is PWM on the levels but not high as there is no reason for it to be on high. They are 5KHz "



Yes. You would be hard pressed to ever detect it, and it would have no ill health, optical, visual, or other effects.


----------



## jon_slider (Dec 16, 2017)

please don't use this thread to debate whether or not PWM or Flicker is acceptable to you, or should be acceptable to others. 

If you have a light that produces flicker, just post the pic of the evidence.

Here btw is the Moon on my Olight Copper S Mini





and the Moon on the Aluminum Klarus Mi1c (clic pic to see source of image)


freeme said:


>


----------



## InvisibleFrodo (Dec 16, 2017)

*Re: List Lights that use PWM or Constant Current that fluctuates*

This thread got me curious, so last night I was playing around with a few lights to try to determine if they had PWM or not.

One of the lights was a copper Beta QRv2 (one of the earliest. I actually ordered a copper QRv1 and what came in the mail was the v2, and then the website got updated.) vs an aluminum Beta QRv1.
I had heard previously that the 2 mode Beta lights had no PWM. I could not detect any PWM on the older 2 mode Beta. However on the copper Beta, I could not get my camera to show the pulse width modulation. I can however hear a high pitched whine coming from the light on low and medium modes. The light is completely silent on high. I can only hear it if the front of the light is near or in my ear. The aluminum version of the light had none of that whine.
The Alpha from Prometheus had easily detectable PWM. That doesn't surprise me because I can hear the Alpha running especially on medium anytime the light is in my hand, no matter how close or far it is from my head. New Alphas come with an upgraded driver, and old Alphas can be upgraded. But on that particular light, the PWM actually stops me from carrying the Alpha because I don't use medium because it's so loud, so I feel like I only have 2 brightness settings that I want to use. I can't wait to get Icarus drivers in all my Alphas.

I could not get the Beagle to show any PWM on camera, and I also couldn't hear any sound.

Next I want to check my Spy 007. Dave says there is no flicker, but I believe he is referring to the newest driver and since I have an XP-G2 Spy, I have the STFu Mk.1

I'm not sure how scientific it is to try to listen for PWM, but I have noticed the sound on lights that use PWM. Could be another means of detection?

Also just to throw it out there, Jason at Prometheus lights does say that his newest driver uses super high frequency PWM and it's supposedly too fast to cause harmonics. That would make it past my sound test while still having PWM...


----------



## jon_slider (Dec 16, 2017)

*Re: List Lights that use PWM or Constant Current that fluctuates*

please use this thread just for posting photos of PWM/Constant Current Flicker. 
I sent you a PM and am happy to discuss your questions in more detail privately, or in another thread.


----------



## Tomchrome (Dec 30, 2017)

*Re: List Lights that use PWM or Constant Current that fluctuates*

Thrunite TH20 - mine is moded with a Nichia 219 (only led swap) but it is rather common knowledge (at least at Polish torch.pl forum) that it uses some PWM (excluding High and Turbo).


----------



## ven (Dec 30, 2017)

47 mini mkII , not on low or medium, but strangely on high only .............. 

Now i dont normally check through my phone, so something must have caught my eye to check it!!! Its not easy to see anyway, and my uses will not be in high as its like 15s


----------



## jon_slider (Dec 30, 2017)

Tomchrome said:


> it is rather common knowledge (at least at Polish torch.pl forum) that it uses some PWM



thanks for the pic, there is also a review here, that agrees there is PWM
http://www.candlepowerforums.com/vb...view-Thrunite-TH20-Neutral-White-(1xAA-14500)



ven said:


> 47 mini mkII , not on low or medium, but strangely on high only



thanks for taking the time to post a photo and share info. That is a very cute light.
this review also found PWM on high https://www.youtube.com/watch?v=OfPi13A_tBI


----------



## ven (Dec 30, 2017)

Thanks Jon, right so its just the way the driver is then, not my sample being a little "iffy" so to speak. All good, luckily its not easy to detect as i tried deliberately after(like you do lol).


----------



## jon_slider (Dec 30, 2017)

ven said:


> its not easy to detect



glad you don't mind
PWM or constant current flicker is most easily photographed if you take an extreme closeup, filling the whole frame, like the image Tomchrome posted.
you might discover PWM or flicker on the low mode as well, if you test it please share your results


----------



## Boris74 (Dec 30, 2017)

Pretty neat info on finding if your light has PWM or some other kind of flicker or whatever. My S1R does it moonlight to 300 lumens. Didn’t try the two turbos. I can’t see it if I use the wave it real fast in the dark method on it. Then I tried the S1A and nothing. No PWM or flicker of any kind on any mode, even moon light. 

I dont care either way, for me PWM gets lost in the trail or whatever else I’m illuminating. Until I see some stills of a hiking trail flickering under PWM, I’m not worried about it. But the testing methods I read here do work. I’m actually pretty surprised the S1R has it with every mode and the S1A doesn’t have it on any. I even tried a couple other friends and family S1R and they did it too. All straight from Olight and all built at different times.


----------



## jon_slider (Dec 30, 2017)

please post a PWM or flicker photo if you would like me to add a light to the list, but your report is welcome as is, since it is searchable

fwiw maukka agrees with your assessment that the S1A is flicker free, and the S1R has flicker (its constant current flicker, not true PWM)
http://www.candlepowerforums.com/vb...RCR123-18650-XM-L2-w-TIR-optics-and-charging)
_The S1R has (visible) PWM at 1750 Hz on moonlight mode only. The S2R doesn't utilize PWM._

http://budgetlightforum.com/node/49380
_PWM is not used, but there is some high frequency switching on the moonlight mode on the S2A. The flickering is noticeable only by video cameras or by moving the light fast, not distracting in real use. S1A has constant current output even on moonlight._


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## ven (Dec 30, 2017)

jon_slider said:


> glad you don't mind
> PWM or constant current flicker is most easily photographed if you take an extreme closeup, filling the whole frame, like the image Tomchrome posted.
> you might discover PWM or flicker on the low mode as well, if you test it please share your results



Could not detect on any other level other than high, i did test them all.


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## RCS1300 (Apr 7, 2018)

In this thread the HDS, Muyshondt Aeon Mk III, and Haiku Mcgizmo 3S are on this list. I own the HDS and Muyshondt. Neither of them have PWM visible to the unaided human eye. Per a post from F89, the Haiku Mcgizmo fixed any pulse with modulation visible to the unaided eye with the introduction of a new 3S in 2012.

Why is this list allowed to remain on CPF? It may be negatively impacting flashlight sales of excellent flashlight makers.


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## Modernflame (Apr 7, 2018)

RCS1300 said:


> Why is this list allowed to remain on CPF as it may be negatively impacting flashlight sales of excellent flashlight makers.



I also cannot see PWM. Sometimes, I still can't spot it even when using a technique known to reveal it. However, the intent of this thread was not to stigmatize a list of flashlight makers. To quote the OP:



jon_slider said:


> This post is not intended to discuss whether PWM is bad, good, or fast enough not to be noticed. It is ONLY about whether the circuit uses pulses.



I do agree with you that some things need to be updated. The current version of the Malkoff Wildcat, for example, uses a high/low resistor ring, and therefore does not achieve low beam through pulses.


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## RCS1300 (Apr 7, 2018)

Modernflame said:


> ...the intent of this thread was not to stigmatize a list of flashlight makers. To quote the OP:
> 
> 
> 
> I do agree with you that some things need to be updated. The current version of the Malkoff Wildcat, for example, uses a high/low resistor ring, and therefore does not achieve low beam through pulses.



Well, this list did make me contact the manufacturer of the McGizmo Haiku prior to purchase to ask for clarification on visible pulse width modulation to the unaided eye. I am really not happy I had to do that!

So, yes this list is having an unintended and detrimental financial impact on flashlight makers.


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## Modernflame (Apr 7, 2018)

RCS1300 said:


> Well, this list did make me contact the manufacturer of the McGizmo Haiku prior to purchase to ask for clarification on visible pulse width modulation to the unaided eye. I am really not happy I had to do that!
> 
> So, yes this list is having an unintended and detrimental financial impact on flashlight makers.



I get where you're coming from. I'm just looking at it the other way around. This forum is a fact finding resource for anyone wishing to make informed decisions about flashlights. Full disclosure prior to purchase is better than shock or disappointment after.

In my opinion, you've assembled a top notch collection of torches, especially the HDS and the Muyshondt. 

Cheers


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## elzilcho (Apr 7, 2018)

RCS1300 said:


> In this thread the HDS, Muyshondt Aeon Mk III, and Haiku Mcgizmo 3S are on this list. I own the HDS and Muyshondt. Neither of them have PWM visible to the unaided human eye. Per a post from F89, the Haiku Mcgizmo fixed any pulse with modulation visible to the unaided eye with the introduction of a new 3S in 2012.
> 
> Why is this list allowed to remain on CPF? It may be negatively impacting flashlight sales of excellent flashlight makers.



I can see the PWM (or whatever it is) on the Aeon's medium mode. I don't even need to wave it around for it to be apparent. It's why I stopped using it, in fact. When I purchased it I assumed it wouldn't bother me in the presence of ambient light, which was my normal use case for the middle lumen level, but it did.

I don't feel it creates a stigma around any particular manufacturer. Not all of Muyshondt's lights have PWM, for example. For those who don't see PWM in use, the list is just a curiosity. For those who do see it, the list can help them more carefully consider their purchase decisions.


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## Boris74 (Apr 7, 2018)

Microstream USB has it on low. It has never bothered me so I buy whatever and don’t worry about it.


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## ven (May 21, 2018)

Fenix cl25r has it on every mode except the lowest...................Can not see by eye luckily, only by phone!


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## vadimax (May 21, 2018)

RCS1300 said:


> In this thread the HDS, Muyshondt Aeon Mk III, and Haiku Mcgizmo 3S are on this list. I own the HDS and Muyshondt. Neither of them have PWM visible to the unaided human eye. Per a post from F89, the Haiku Mcgizmo fixed any pulse with modulation visible to the unaided eye with the introduction of a new 3S in 2012.
> 
> Why is this list allowed to remain on CPF? It may be negatively impacting flashlight sales of excellent flashlight makers.



Perhaps, you’ve got nothing in common with spinning blades, machinery, etc. Just for your education: once PWM makes a precise multiple of RPM of rotating machinery parts, human eye registers them as static when in reality they spin violently. This is a direct path to severe injuries or death of an operator.

Visually this looks like:



just replace “shutter speed” with “PWM”.


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## KITROBASKIN (May 21, 2018)

vadimax said:


> Perhaps, you’ve got nothing in common with spinning blades, machinery, etc. Just for your education: once PWM makes a precise multiple of RPM of rotating machinery parts, human eye registers them as static when in reality they spin violently. This is a direct path to severe injuries or death of an operator.
> 
> Visually this looks like:
> 
> ...




Anyone poking their hands in machinery using any flashlight without sufficient ambient illumination needs to be careful, regardless of high frequency PWM.

And seems like the sound and displacement of air with Helo rotors would be a clue to movement.


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