# List Lights that use NO PWM



## jon_slider (Mar 13, 2016)

*List Lights that use NO PWM, nor pulses, and are true Constant Current*

*Lights with NO PWM, no Pulses, and are true Contant Current lights:*

Acebeam K70
Astrolux aka Manker A01 (note the latest since Oct? 2016, Astrolux A01 uses PWM if the driver is not marked Manker)
Astrolux M01 and M03
Convoy S2 UV
DQG 18650 Tiny IV
Fenix E05
Fenix PD35
Lumintop Tool 
Lumintop Worm
Maratac AAA
McGizmo Sapphire
Manker E02
Manker LAD (Constant current with a feedback loop)
MecArmy PT-18 
Muyshondt Aeon Mk3 an example of a regulated current light that has visible flicker, even if it is not technically PWM..
Nitecore Tip (disputed) photo shows bands caused by the LED cycling brighter and dimmer (strobing):






Olight i3s
Olight S1A see reviews: #1, and #1
Oveready Boss boss video
PKDL
Streamlight 2016
Thrunite AAA Titanium Christmas
Thrunite AAA Ti3, TiS, TiXmas
Zebralights controversial, photo shows very faint pulses. Plus scan lines in a photo, in this post #74
left to right Zebra, Quark, Eagletac, Malkoff 




The Zebra pulses do not drop to zero and you can see the blurr almost completely hides the dots. Zebra markets the light as having Constant Current, and in the photo it is almost impossible to capture the dots. The LED does not turn all the way off, so technically it is not using PWM.

The Quark is blurred between the dots, it is marketed as a Constant Current light, because the flashes of light do not turn completely off, its more of a dim then bright, rather than off then on, power cycling.

The Eagletac dots have no blur, which suggests the LED is turning all the way off, but on an oscilloscope the dimming phase shows there is still some power to the LED, so not technically full PWM, but still discrete pulses of light that a camera can capture. Eagletac markets the light as having no PWM, which technically is accurate, since the led is flashing brighter and dimmer, not fully off and on.

The Malkoff uses PWM and the manufacturer discloses it. You can see there is no blurr between the Malkoff pulses.


----
By NO PWM I mean NO. Please don't list lights that use PWM but you don't notice, or are not bothered by, the PWM. My sig link has a thread containing lights with YES PWM.

AAA Lights made by Lumintop after approximately October 2015 forward use NoPWM, this includes the Tool and the Maratac AAA (earlier versions were YES PWM):
(the NoPWM Lumintops have a ring around the LED as pictured on right)








The lights listed above have NO PWM AND use *CONSTANT CURRENT* (waving the light does not produce dots, and or a scope does not show pulses, and or reviews confirm NoPWM, and or a photo does not have interference lines)


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## FRITZHID (Mar 13, 2016)

There are plenty of lights/drivers that DO use PWM but at such a high frequency that you, your camera.... Anything but a slow-mo camera or oscilloscope won't notice, in fact, I'd bet the majority of "non-PWM" lights you know DO in fact use PWM but they are a higher freq and quality.


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## twistedraven (Mar 13, 2016)

Forgive me for sounding like a devil's advocate, but if one isn't bothered or can't detect any PWM on a light, yet it has it anyways, then why not recommend it?


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## jon_slider (Mar 13, 2016)

FRITZHID said:


> I'd bet the majority of "non-PWM" lights you know DO in fact use PWM but they are a higher freq and quality.



can you give an example of which light I have listed above as NOPWM, which you can show evidence of having PWM.. Evidence such as Oscilloscope picture would be awesome



twistedraven said:


> if one isn't bothered or can't detect any PWM on a light, yet it has it anyways, then why not recommend it?



this thread is not meant to debate whether PWM matters or not. And Im not recommending for or against PWM. Im just trying to list lights in this thread that do NOT use PWM. Basically, just the Facts.

There are many, many, many lights that are very very popular that use PWM, you can see a partial list in my YES PWM list. Im not trying to tell anyone which lights to buy, and Im not trying to say that lights with PWM, or without PWM are better or worse than the other.

Just the facts, does a light HAVE NO PWM, then please list it here. afaict, the list is MUCH shorter than the list of lights in the other thread that have YES PWM.


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## twistedraven (Mar 13, 2016)

Ok, well, I do know that any Zebralight uses no PWM. I was surprised that the Eagletac D25LC2 uses PWM now that I'm reading your other thread, I don't recall ever noticing it or being bothered by it.


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## jon_slider (Mar 13, 2016)

twistedraven said:


> Ok, well, I do know that any Zebralight uses no PWM. I was surprised that the Eagletac D25LC2 uses PWM now that I'm reading your other thread...



there is no concensus on those two lights, so out of respect for keeping an open mind, I have added them to the first post

some people say they Do use Pulses, others say they never drop all the way to zero between pulses, so by the strict definition of PWM they say those lights dont use PWM, but the scopes do show pulses.. selfbuilt refers to it as an "unusual sawtooth pattern of circuit noise" in reference to the Eagletac, so he can see the same thing others see, but follows the "does not drop to zero" definition of PWM, so he does not "call it" PWM.

I sent you PM to discuss this in more detail, I welcome your thoughts


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## jimmy1970 (Mar 14, 2016)

HDS Clicky/Rotary.


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## jon_slider (Mar 14, 2016)

jimmy1970 said:


> HDS Clicky/Rotary.


Thanks! I learned something from you, much appreciated.. added to the first post with link to factory info


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## SemiMan (Mar 14, 2016)

jon_slider said:


> Thanks! I learned something from you, much appreciated.. added to the first post with link to factory info




"We use a more sophisticated algorithm for dimming the LED that minimizes both the amount of tint shift and the annoying flickering while increasing the total system efficiency." .. from HDS website

... this means they use some type of pulse modulation.


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## ven (Mar 14, 2016)

Yes , i was under the impression also SemiMan that HDS uses a form of PWM to limit the tint shift. I can not detect it and the tint to me stays the same throughout the brightness span.


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## SemiMan (Mar 14, 2016)

ven said:


> Yes , i was under the impression also SemiMan that HDS uses a form of PWM to limit the tint shift. I can not detect it and the tint to me stays the same throughout the brightness span.



The most efficient drive is pure constant current to about 10%, then pulse modulation below that. That optimizes the LED and generally the driver too.

It could be a matter of how they think it behave and how it really does not being exactly the same.

It could require a fairly high speed optical detector to detect it with a scope. 100-200KHz pulsing is possible and as the signal is not regular, could be hard to sync.

Semiman


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## sunny_nites (Mar 14, 2016)

The mighty Illuminex-4. Two modes, no PWM.


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## bykfixer (Mar 14, 2016)

PK said his FL2 do not use PWM to achieve low setting.

Now any other TLA way of it? I dunno. He did not say. 
I'll check later to see if lines show up in the camera display or photo.


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## jon_slider (Apr 11, 2016)

added Astrolux aka Manker A01, now available in Copper also


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## og44 (Jul 5, 2016)

McGizmo Sapphire uses constant current driver at 25mah. I think that means no pwm.


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## jon_slider (Jul 5, 2016)

og44 said:


> McGizmo Sapphire uses constant current driver at 25mah. I think that means no pwm.



I agree. 
Usually PWM is not needed for single mode lights, and also not needed on the high mode of multi mode lights. Its the lower modes, that are dimmed, such as on the Haiku, that use PWM for dimming.

btw, here is some PWM info I got from Malkoff:

"All of the multimode MDC Flashlights use PWM. The PWM frequency is 310 Hertz."

note that those are lights that use more than one mode, it fits the pattern that they are multi mode lights that use PWM


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## wle (Jul 6, 2016)

DQG 18650 Tiny IV

wle


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## jon_slider (Oct 31, 2016)

added nitecore Tip


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## LeanBurn (Oct 31, 2016)

Would it be safe to say that no ThruNite lights use PWM?


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## Genius1 (Oct 31, 2016)

OrcaTorch T11, solid AA light.


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## rookiedaddy (Nov 2, 2016)

jon_slider said:


> added nitecore Tip


The following was captured using F/1.7, Exp: 1/3000 sec, ISO 100. All Nitecore TIP in Mid mode (tested the same in High mode).





Does that mean Nitecore TIP uses PWM? very high frequency? :shrug:

Edit: using another camera, I detected the "lines" at exp: 1/1500 and above too...


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## WarriorOfLight (Nov 2, 2016)

rookiedaddy said:


> Does that mean Nitecore TIP uses PWM? very high frequency? :shrug:


Yes 

In general PWM is not a bead thing. It is only important the PWM frequency is not too low. The advantage using PWM is not getting the ugly bad green tint in comparsion the current is reduced to dim the LED.


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## vadimax (Nov 2, 2016)

WarriorOfLight said:


> Yes
> 
> In general PWM is not a bead thing. It is only important the PWM frequency is not too low. The advantage using PWM is not getting the ugly bad green tint in comparsion the current is reduced to dim the LED.



PWM may be extremely dangerous when you work/maintain some machinery with rotating/moving parts. Due to PWM they will look static while violently rotating...


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## WarriorOfLight (Nov 2, 2016)

vadimax said:


> PWM may be extremely dangerous when you work/maintain some machinery with rotating/moving parts. Due to PWM they will look static while violently rotating...


That is correct, but I'm pretty sure 99.999% here @CPF do not want PWM because of flickering, not because of the detection of moving/rotating parts.


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## LeanBurn (Nov 2, 2016)

PWM makes me feel bit queasy so I don't choose lights that have it. Some people have no issues with it.


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## Lexel (Nov 2, 2016)

WarriorOfLight said:


> Yes
> 
> In general PWM is not a bead thing. It is only important the PWM frequency is not too low. The advantage using PWM is not getting the ugly bad green tint in comparsion the current is reduced to dim the LED.




that is why some manufactors use pwm in very low modes, while medium and high stays CC


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## Lexel (Nov 2, 2016)

rookiedaddy said:


> The following was captured using F/1.7, Exp: 1/3000 sec, ISO 100. All Nitecore TIP in Mid mode (tested the same in High mode).
> 
> 
> 
> ...



if you want eliminate flicker get a slower shutter speed than the camera can do the picture in one piece
if its faster the camera will do multiple pictures at different times to manage to get the whole aperature light


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## jon_slider (Nov 2, 2016)

rookiedaddy said:


> Does that mean Nitecore TIP uses PWM?



Yes, Thank You! Removed Tip from NoPWM list, added to YES PWM list.

as far as determining frequency, maybe contact Lexel and ask how he made the photo in this link

as far as everyones opinion about whether PWM is good bad or meaningless.. there is a sticky about PWM at the top of the LED forum page. Maybe take your discussion there.

I only intended this thread to be a list of lights, not really a discussion/argument about the pros and cons of PWM.

Whether PWM matters is a very controversial subject. Everyone is entitled to their own opinion.

The bottom line is simple, YES, the TIP has PWM. thanks to rookiedaddy for proving it.


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## Lexel (Nov 2, 2016)

you can do this in your shower without a camera to identify if its PWM
you will see with your eye easily the droplets in small points falling if its pwm on low mode

a camera can be used to get the frequency with as few % unaccuracy 
multiple the number points with the 1/shutter time 
for example my last picture here 44 x 100 = 4400Hz

if the shutter speed is too short the number of points is too small to calculate the pwm frequency
as the drops are moving its not a problem, but if you light a wall and use 1/3000s you will get horizontal differences in intensity, bcs of how the camera works to get a whole picture at fast shutter times
the slower the pwm frequency is the more it will affect the camera in worst case you will see big horizontal areas without any light

so its best to lower the cameras ISO and increase the aperture till you reach the same time as the camera could syncronize a flash
1/1600s





1/200s





1/100s


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## rookiedaddy (Nov 2, 2016)

Lexel said:


> you can do this in your shower without a camera to identify if its PWM
> you will see with your eye easily the droplets in small points falling if its pwm on low mode
> 
> a camera can be used to get the frequency with as few % unaccuracy
> ...


Thank you for the detail explanations. :twothumbs


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## NitecoreStore (Nov 4, 2016)

I would like to add some personal options based on my observation of PWM and TIP.

PWM (Pulse Width Modulation) is used to control the average power output by adjusting the duty cycle which is the ratio of high pulse vs zero output. 

We tested the TIP output with an Oscilloscope. What we observed is a constant line with a small oscillating wave of 4K Hz and 5% peak up/down overlapped on it. Adjusting the intensity shifts the height of constant output but does not change the frequency or percentage of the oscillating wave. That, to my best knowledge, is not PWM. 

Can a camera shot tell the difference between a PWM wave and a constant output with a small fluctuation as described above?


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## jon_slider (Nov 4, 2016)

NitecoreStore said:


> We tested the TIP output with an Oscilloscope. What we observed is a constant line with a small oscillating wave of 4K Hz and 5% peak up/down overlapped on it. … That, to my best knowledge, is not PWM.
> 
> Can a camera shot tell the difference between a PWM wave and a constant output with a small fluctuation as described above?



I agree that the strict definition of PWM is ON OFF cycles and that the pulsed cycle you measured is Bright Dim cycling, so not technically PWM, but still a fluctuating brightness level.

I wondered the same thing you did about the ability of a camera to tell the difference between PWM and Bright Dim cycling. Yes. I believe it can. 

L > R, SC52, Quark AA, D25A, MDC AA



In the above photo notice the barely visible dots from the Zebralight, which like the Tip is Not technically PWM, it is only Pulsed.

similarly, looking closely at the scan lines of rookiedaddys Tips, they appear "fuzzy", particularly they dont show full dark segments. 





in contrast to the old model Tool




I believe this fits with your observation that the bright dim cycles of the Tip are not true ON OFF cycles that is the technical definition of PWM.

Thank you very much for sharing your oscilloscope info… I will add "disputed" to my post that lists the Tip as a PWM light, as it is technically only a Pulsed light source, not true On Off PWM.

fwiw, pulses that do not drop to Zero, and are not technically PWM can still be visible to people who know what to look for (and to a camera), Pulses that are not PWM are not the same as Constant Current.. here is an example on a Jaxman E2


maukka said:


> "PWM/pulsing is used on low and medium. Even though the output never drops to zero and the cycling frequency is rather high at 3900 hertz, it is still possible to see when looking directly at the light and moving either eyes or the light very rapidly."


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## chillinn (Nov 5, 2016)

Outstanding thread, jon_slider. 

If this thread were a democracy, I would vote that you remove Eagletac and Zebralight from the list, and any similar lights that use ways to mask what is in effect PWM, regardless of the technicalities. Though they make outstanding lights, and even though I don't usually notice PWM in my SC5w, I find that using ZL for long periods in some of the modes tends to accellerate eye-weariness (I don't believe this matters for most people, even those sensitive to PWM, who only use flashlights like normal people, i.e. occasionally). In keeping with the spirit of why you created this thread and its sister thread, which is obviously because you grow as tired of PWM-evangelism as you do of PWM, to cut through all arguments, to make the world black and white, either it does or it doesn't... I can't believe you even considered adding them to your NO PWM list, much less actually did, which I see you have. I urge you to reconsider and stick with your convictions.

I don't see any mention of _other_ Thrunite engines. I believe they are all constant current designs. Also, McGizmo "AA converter" light engines. I saw a post in another forum, however, showing an image purportedly from an AA McGizmo that exhibited the telltale artifacts of fast PWM, but I'm really not certain what engine the poster was using.


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## ven (Nov 5, 2016)

Yes outstanding thread by jon, unfortunately i am going to have to crown him the PWM king.............no doubt not to his liking!


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## chillinn (Nov 5, 2016)

Among all the possible describable characteristics of a flashlight, whether it uses PWM is one of the most neglected, and suspiciously so.

jon, I believe Fenix uses NO PWM drivers, but I only know this at least for their more recent AAA designs. I have seen Fenix marketing educating the consumer on PWM, so this leads me to believe Fenix doesn't use PWM (any more), but, again, I'm not quite certain if that is univerally true about Fenix.


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## chillinn (Nov 5, 2016)

duplicate
.
.


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## jon_slider (Nov 5, 2016)

chillinn said:


> I would vote that you remove Eagletac and Zebralight from the list, and any similar lights that use ways to mask what is in effect PWM, regardless of the technicalities.



thank you
removed Eagletac, HDS, and Zebralight because though they are not CONSTANT Current

_*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_

see the YES PWM thread for more detail
List-Lights-that-use-PWM

Regarding lights that I have not listed, such as other Thrunite models. I agree the Thrunites I have owned do NOT use PWM. Feel free to add other models to this thread, even if not posted on the first page. Do include evidence or a reference to support your opinion.

ps, I edited the title of the first post to clarify that the NOPWM list only includes lights with NOPulses, and use True *Constant Current*, NOT just lights that do not meet the technical definition of PWM but still use Pulses.



ven said:


> Yes outstanding thread by jon, unfortunately i am going to have to crown him the PWM king.............no doubt not to his liking!



Im honored! LOL
It seems the term PWM has a weasel clause, so I would like to be called the *Constant Current* King instead :twothumbs


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## chillinn (Nov 5, 2016)

"Constant Current" is what everyone used to refer to "NO PWM" as, often abbreviating CC. While it sounds more ambiguous, it is deceivingly more accurate. Micro-electronics, I have figured out after decades of being in awe of even digital watches, can be pretty complex, and there even exist flashlights with circuits that use PWM and yet the brightness of the emitter is legitimately constant, actually without any PWM artifacts or pulsing schemes, visible or invisible, and it has nothing to do with frequency rates. I think also any incandescent that utilizes PWM is possibly a decent light source with a constant light output. I don't think this waters down the problematic issue that there are too many LED flashlights that use PWM the way we hate, and there is no way to know about it until you have already spent the money and used it, meaning, it's not exactly the kind of feature that ever makes feature lists used in marketing materials, unless it is the opposite, an affirmation of a constant current design.

So it can be a sticky subject with so many lights with so many things right with them losing a customer ultimately because of their lucky realization the designer/manufacturer/seller has a "what the customer doesn't know won't hurt them" underlying philosophy.


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## TheBelgian (Nov 7, 2016)

chillinn said:


> If this thread were a democracy, I would vote that you remove Eagletac and Zebralight from the list, and any similar lights that use ways to mask what is in effect PWM, regardless of the technicalities. Though they make outstanding lights, and even though I don't usually notice PWM in my SC5w, I find that using ZL for long periods in some of the modes tends to accellerate eye-weariness (I don't believe this matters for most people, even those sensitive to PWM, who only use flashlights like normal people, i.e. occasionally).



I don't think Zebralight uses PWM or suffer from any kimd of flickering. I haven't found anything in my Zebralights (sc52w and h52fw) and none of Selfbuilt's reviews found any signs of flickering with an osciloscope. Only the the sc52 with 14500 had some problems but that was a generation ago.


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## jon_slider (Nov 7, 2016)

TheBelgian said:


> I don't think Zebralight uses PWM


true, the PWM weasel clause applies to Zebras. They use Pulses that are not PWM by technical definition, since the Pulses do not drop to Zero. 
However the fact Zebras do not use PWM does not mean they use Constant Current. In fact, Zebras do NOT use Constant Current.. clic pic for more info


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## TheBelgian (Nov 10, 2016)

jon_slider said:


> true, the PWM weasel clause applies to Zebras. They use Pulses that are not PWM by technical definition, since the Pulses do not drop to Zero.
> However the fact Zebras do not use PWM does not mean they use Constant Current. In fact, Zebras do NOT use Constant Current.. clic pic for more info


I see there is some fluctuation of the output of the sc5fc, but it isn't pwm and more importantly, the fluctuations are said to be so low they can't be seen by eye. I don't know the absolute scale of the scope diagrams, but if say the light fluctuates between 100% and 90% that won't be noticable and has no notable impact on effeciency, so for all intents and purposes it has no PWM. Other lights like for instance the Fenix LD60 should be constant current but there the fluctuations are so great it does cause visible flickering which is as bad as having PWM.
This should be a list of lights with no visible flickering (although extreme high frequency PWM should still be counted as flickering)
<\2cents>


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## TheBelgian (Nov 10, 2016)

Double post, crazy smartphone


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## TheBelgian (Nov 10, 2016)

The scope traces you've shown are zoomed in on the fluctuations, on the absolute scope traces the fluctuations are in the 10% range, not perceptible.
Also, constant current circuits always have some noise. Perfectly flat constant current output is impossible (unless using linear regulators, with lower efficiency as downside), especially in small form factor lights like the Zebralight.
I'm not advertising for Zebralight, but I find excluding Zebralight for invisible output fluctuations (which many if not all constant current lights have) seems unfair.


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## bykfixer (Nov 10, 2016)

None of the PKDL line up uses PWM.
Heck no step down for that matter. 

Streamlight is getting away from PWM in 016 lights.


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## jon_slider (Nov 10, 2016)

bykfixer said:


> None of the PKDL line up uses PWM.
> Streamlight is getting away from PWM


very helpful, thank you



TheBelgian said:


> on the absolute scope traces the fluctuations are in the 10% range, not perceptible.
> ...
> I find excluding Zebralight for invisible output fluctuations (which many if not all constant current lights have) seems unfair.



I respect and appreciate the points you've raised. 
I've added zebra to the list of lights with no PWM while we continue our discussion.

I don't own a zebra, if you do, could you please test: the beam close up, waving, and water drops tests listed below?

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.
3. Dots visible in photographs, while waving the light. 
4. Dots visible in photos of shower water drops. 

Additional areas of inquiry:
At what x% flux and at what frequency on scope traces, is there no photographic evidence from waving or water drop tests?

What is the %flux of zebralights and at what frequency. 

List the %flux and oscilloscope measured frequency of some representative lights that use pulses that are visible in beam and led photos.


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## TheBelgian (Nov 11, 2016)

I don't hhave a scope, but I'll try to do a photographic shower test next week.
An eyeball shower test doesn't show anything, but lets get some cold hard scientific objectivity. Next week.


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## bykfixer (Nov 11, 2016)

Just aim it at a fan turned on and take pix of the fan...




With PWM




Without


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## jon_slider (Nov 11, 2016)

for anyone interested in helping reconcile the pulses maukka showed, and the opposing view of selbuilt, below is some reference info to consider.. (these are why the Zebralight is on the lights with PWM list, with a disclaimer that it is controversial). note maukka has since posted that PWM was a bad choice of words, as the pulses dont drop to full zero, per the technical definition of PWM.. which is why IM now asking for the other photographic tests…. (besides the scopes)




TheBelgian said:


> I don't hhave a scope, but I'll try to do a photographic shower test next week.
> An eyeball shower test doesn't show anything, but lets get some cold hard scientific objectivity. Next week.



thanks
the scope pics for SC5 are pretty much covered by maukka


====
maukka's review of the SC5 
"PWM
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."


maukka's SC5 scope readings http://imgur.com/a/IbSg6


====
selfbuilt's opinion on the SC5 (no scope shown)
http://www.candlepowerforums.com/vb/showthread.php?403440
"PWM/Strobe
As with my other Zebralight lights, I don't see any signs of pulse width modulation (PWM) on any the lower output modes. The light appears to be fully current controlled at all levels. "


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## TheBelgian (Nov 11, 2016)

I don't have a SC5, only an SC52, so I can't do a straight apples to apples comparison. But I can still check for flicker.
I'll check all my lights (way to many) to see if I find non PWM flickering (I have no PWM lights)


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## chillinn (Nov 14, 2016)

TheBelgian said:


> ...it isn't pwm and more importantly, the fluctuations are said to be so low they can't be seen by eye...



All things being equal, you have 2 near identical Zebralights, one pulses like the stock version, but the other uses a legitimately constant current and true constant light output, no pulsing or PWM-like tricks. Battery life is identical, and because Zebralight is already a premium cost light, the retail price is identical. Which would you choose?

Herein lies the problem with the argument others have long made, saying, more or less, if you can't see PWM, then PWM doesn't matter. If I hid something in your living quarters that smelled like feces, but wasn't actually feces, somewhere you couldn't smell it, you won't mind? Not being able to detect PWM instantly with normal vision has no bearing on the evils of PWM. Sometimes, one only suspects PWM, and doesn't literally detect it, because after using a light for 2 hours a migraine sets in, or exhaustion. It is hard to predict that beforehand, and afterwards it's too late to do anything about it. 

The argument seems to always be between one side that _doesn't care_, and the other side that does... but somehow, oddly, the side that doesn't care often ends up evangelizing, campaigning for, PWM, which is absurd, because they don't care. 

PWM is bad, and so is anything even remotely like PWM, such as pulsing 10% dips in brightness on a frequency of 75kHz. There is nothing one can argue from the vantage point of "I don't care about PWM" to mitigate the evil of PWM. 

And it's frustrating because it is not a "different strokes" kind of thing. You have a population that doesn't care their lights use PWM, or variable light output somehow or are unaware of it, and a minority population that ranges from prefer to not have PWM to can't tolerate PWM, and because the I-don't-care's are large enough to drive what is made and sold, the minority will be ignored by major manufacturers. But I bet most of the i-don't-care's or i-don-know's that are made aware of it, if offerred an identical light for an identical price without PWM, would choose the one without PWM. Wake up people! Don't be so complacent with "good enough," we deserve not just better... we deserve the best possible, and we are glad to pay a premium for it.


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## Lexel (Nov 15, 2016)

So if you buy a DC psu, that has 2% ripple at 21kHz from switching is that not a DC power supply anymore?
or good old style PSU just AC 4 bridge rectifier with proper sized capacitor
I can plug in my DC stuff and it works, while it would smoke on AC 

if a light gets a few % ripple and the only way to detect it is zooming in on my Oszilloscope why should that not be a CC light?


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## chillinn (Nov 15, 2016)

Lexel said:


> So if you buy a DC psu, that has 2% ripple at 21kHz from switching is that not a DC power supply anymore?
> or good old style PSU just AC 4 bridge rectifier with proper sized capacitor
> I can plug in my DC stuff and it works, while it would smoke on AC
> 
> if a light gets a few % ripple and the only way to detect it is zooming in on my Oszilloscope why should that not be a CC light?



PWM, or switching, used elsewhere in the circuit where it is not affecting light output, where it is not an intentional scheme to trick the eye into thinking the light is constant, but is as constant as CC is, then that's not what we're complaining about. 

Let's not confuse one PWM with another. jon_slider is pretty specific, but just saying 'PWM and the like' is apparently ambiguous to some. What I believe he is specifying with NO PWM is any engineered circuit intended to trick the eye into thinking the light output is a constant level when in fact it is flashing faster than the eye detects, whether to zero or 2%, whether for 200ms or Planck time. 

idky the convesersation always ends up like this... https://www.youtube.com/watch?v=anwy2MPT5RE 

I understand flashaholics have their favorite lights, and they are their favorite even if they use PWM, but taking the worst feature out of your favorite light shouldn't scale to all other lights, yet this is what has happnened. Because a favorite light has PWM, the PWM wars continue. 

Would anyone anywhere ever complain if PWM simply vanished from the Earth never to return? Honestly, I have no idea what I'm trying to accomplish. Thanks jon_slider. Peace.


----------



## vadimax (Nov 15, 2016)

Lexel said:


> So if you buy a DC psu, that has 2% ripple at 21kHz from switching is that not a DC power supply anymore?
> or good old style PSU just AC 4 bridge rectifier with proper sized capacitor
> I can plug in my DC stuff and it works, while it would smoke on AC
> 
> if a light gets a few % ripple and the only way to detect it is zooming in on my Oszilloscope why should that not be a CC light?



Imagine two bottles of water: one from deep drill mineral water source, another is sewerage recycling product. They look the same and have no smell. Which one would you drink?

PWM is poor engineering to make things as cheap in production as possible to get the most interest selling that crap. I prefer not to buy crap and sewerage recycling.

P.S.: Regarding "ripple" in supposed to be DC -- any inductive coil and the whole circuit becomes an EM emitter, making the whole system less energy effective and more noisy in radio band.


----------



## Lexel (Nov 15, 2016)

vadimax said:


> Imagine two bottles of water: one from deep drill mineral water source, another is sewerage recycling product. They look the same and have no smell. Which one would you drink?
> 
> PWM is poor engineering to make things as cheap in production as possible to get the most interest selling that crap. I prefer not to buy crap and sewerage recycling.
> 
> P.S.: Regarding "ripple" in supposed to be DC -- any inductive coil and the whole circuit becomes an EM emitter, making the whole system less energy effective and more noisy in radio band.



there are enough drivers which use buck converters and CC to drive the flashlight
it is needed in all lights with single cell and XHP35, 50 and 70 LEDs
so we do also classify them now PWM lights as their voltage gets amplified by PWM and it is impossible to get a CC without ripple/HF noise out of it

while PWM is clearly definied to adjust output by switching On/Off!


----------



## vadimax (Nov 15, 2016)

chillinn said:


> "Constant Current" is what everyone used to refer to "NO PWM" as, often abbreviating CC. While it sounds more ambiguous, it is deceivingly more accurate. Micro-electronics, I have figured out after decades of being in awe of even digital watches, can be pretty complex, and there even exist flashlights with circuits that use PWM and yet the brightness of the emitter is legitimately constant, actually without any PWM artifacts or pulsing schemes, visible or invisible, and it has nothing to do with frequency rates. I think also any incandescent that utilizes PWM is possibly a decent light source with a constant light output. I don't think this waters down the problematic issue that there are too many LED flashlights that use PWM the way we hate, and there is no way to know about it until you have already spent the money and used it, meaning, it's not exactly the kind of feature that ever makes feature lists used in marketing materials, unless it is the opposite, an affirmation of a constant current design.
> 
> So it can be a sticky subject with so many lights with so many things right with them losing a customer ultimately because of their lucky realization the designer/manufacturer/seller has a "what the customer doesn't know won't hurt them" underlying philosophy.



I am sorry, but you cannot compare LEDs and incandescent bulbs in regard to PWM. White-hot tungsten wire works as a stabilizing scheme -- it just physically unable to cool down during an "off" phase and thus effectively eliminates PWM in its emission. On the contrary LED is capable to pass on-off front instantly.


----------



## eraursls1984 (Nov 15, 2016)

I hate easily visible PWM, but overall its not that bad IMO. One thing no one seems to take into account is the bad tint shift from constant current lights. Maybe you guys only use max mode, but I use moonlight and low modes most often. Newer CC lights seem to be better, I'm not sure if it's the improved electronics or LED. 

IMO, crappy low frequency PWM lights been to die. However , there is a place for high frequency PWM, constant current , and in between (Zebralight pulsing).


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## jon_slider (Nov 15, 2016)

Gentlemen, thank you for the dialogue. Before this thread devolves into polarized perspectives on the pros and cons regarding PWM in flashlights, the merits of Chinese manufacturing priorities, etc, I would like to propose that we use some specific criteria to determine whether the circuit in any specific light has measurable effects.
----

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.
3. Dots visible in photographs, while waving the light. 
4. Dots visible in photos of shower water drops.

----

*Can someone who owns a Zebralight please provide the results of those 4 tests?*


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## TCY (Nov 15, 2016)

I emailed ZL about this and here's their reply:
_Constant current regulators always use a feed back circuitry to measure the output current (that passes through the LED) and adjust the supplying power (up and down) to the LED accordingly. The action itself has (up and down) ripples. Good circuitry designs usually make the ripples so minuscule and/or fast enough, relative to the LED output, that they won't be seen by human eyes. 
You'll need a digital camera with a global shutter (rather than a typical rolling shutter) or a traditional film camera to detect flashlight PWMs properly.

_I did tests 2-4 and see no signs of flickering or PWM. If I get some time today I'll see if I can repeat this and upload the photos.


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## jon_slider (Dec 1, 2016)

I found a photo of Zebralight that shows me it uses a type of Pulses that is not full PWM, but can be photographed.

As you can see in the photo below, in the sweep of the Zebralight, the dots blur together, almost completely, because the LED is getting brighter and dimmer, really quickly, but without turning all the way off. (I suspect this increases battery life)

Only the Malkoff in the photo uses true PWM, note that the dots have dark spaces between them, while the "circuit noise" lights have blurry light between the dots pictured. 

My opinion: Zebralight and Eagletac, to me, are not techically Constant Current lights, but technically they also are not PWM. For me the bottom line is that both lights have dots that can be photographed.



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.
> 
> 
> 
> ...




I am listing the "controversial" lights, such as Zebralight, on both the lights with PWM and the lights with NoPWM threads, with explanations.


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## jto (Dec 4, 2016)

I happen to have an interest in the PWM characteristics because video cameras yadda yadda, I really want temporally smooth light (and high CRI). Asked Zebralight directly, and they were quick to respond:



> None of our flashlights or headlamps in production now uses PWM (or any other type of pulsing mechanisms) in controlling different brightness levels. That said, constant current brightness control, being a control system, will have circuit noise or ripple no matter how small it is. But I don't think you'll be able to see any of these (relatively) small amplitude noise in still photos taken by a digital camera with either a global or rolling shutter. Not sure about the video though, especially if the scene involves fast moving objects with a dark background and a rolling shutter camera.There is no need for ND filters for shifting to particular brightness because all levels are controlled by the same (constant current) circuitry.



It should be noted that this may apply only to the H600/SC600 series or newer, as those what was I told I was interested in. Seems to be in line with the picture in the above post, "minimal ripple" seems more accurate description than any kind of "pulse".


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## chillinn (Dec 4, 2016)

jto said:


> > None of our flashlights or headlamps in production now uses PWM (or any other type of pulsing mechanisms) in controlling different brightness levels.



I'd be ecstatic if that were true. I have 2 Zebralights, SC5w and SC62c, and my research here convinced me neither used PWM. Then I bought and used them. They both behave identically, have the same UI. It's not that I noticed PWM, what I noticed was the onset of headaches all the way up to migraine when using certain modes more than others. At the very least, the brightest low mode on both has some sort of PWM-like pulsing mechanism that is visually detectable if looking for it the way we look for PWM, and both the lower medium modes have it also. These were my 3 most-used modes, used for hours on end as the single light source in a room. 

I was devastated to discover the headaches were being caused by these Zebralights. These lights are flashlight-perfection in many ways... the single gripe I have is that they *definitely are not fully Constant Current drivers on all modes*, their single and glaring flaw. And this is certainly not circuit noise, but an intentional scheme to prolong runtime. If I instead use the ReyLight Cu Tool as a single light source, a known CC driver, I get no headaches. But I grow weary of AAA capacity when using a flashlight this way, not as a task light, but as a room lamp. I realize few use flashlights as lamps unless they are camping, but I'd rarely get to use a flashlight if I only used them when needed for flashlight tasks.

If Zebralight has changed something in their drivers since I purchased mine (mid-2016), if they are indeed actually and factually fully constant current without a PWM-like pulsing scheme, then I will be a return customer. But this change in Zebralight driver to fully CC must be proven here first before I'd consider shelling out so much for one again.


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## jon_slider (Dec 4, 2016)

jto said:


> "minimal ripple"


if Zebra has a new driver that does not show minimal oscilloscope ripples or photographable dots, please share photos.



chillinn said:


> I was devastated to discover the headaches were being caused by these Zebralights. These lights are flashlight-perfection in many ways... the single gripe I have is that they *definitely are not fully Constant Current drivers on all modes*
> ...
> If I instead use the ReyLight Cu Tool as a single light source, a known CC driver, I get no headaches.



Thank you for sharing your direct experience of the effect of the latest Zebralight SC5 on your brain.

I will leave the Zebras on this NoPWM list, and also on the YesPWM list, as one of the "controversial" lights
imo Zebras use a hybrid system that is neither pure PWM nor pure Constant Current.


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## Trango (Dec 7, 2016)

@ jon_slider
my Fenix E05 SS does not seem to have PWM, did the camera test on low and medium and it always appears as a full line.


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## Tachead (Dec 24, 2016)

chillinn said:


> I'd be ecstatic if that were true. I have 2 Zebralights, SC5w and SC62c, and my research here convinced me neither used PWM. Then I bought and used them. They both behave identically, have the same UI. It's not that I noticed PWM, what I noticed was the onset of headaches all the way up to migraine when using certain modes more than others. At the very least, the brightest low mode on both has some sort of PWM-like pulsing mechanism that is visually detectable if looking for it the way we look for PWM, and both the lower medium modes have it also. These were my 3 most-used modes, used for hours on end as the single light source in a room.
> 
> I was devastated to discover the headaches were being caused by these Zebralights. These lights are flashlight-perfection in many ways... the single gripe I have is that they *definitely are not fully Constant Current drivers on all modes*, their single and glaring flaw. And this is certainly not circuit noise, but an intentional scheme to prolong runtime. If I instead use the ReyLight Cu Tool as a single light source, a known CC driver, I get no headaches. But I grow weary of AAA capacity when using a flashlight this way, not as a task light, but as a room lamp. I realize few use flashlights as lamps unless they are camping, but I'd rarely get to use a flashlight if I only used them when needed for flashlight tasks.
> 
> If Zebralight has changed something in their drivers since I purchased mine (mid-2016), if they are indeed actually and factually fully constant current without a PWM-like pulsing scheme, then I will be a return customer. But this change in Zebralight driver to fully CC must be proven here first before I'd consider shelling out so much for one again.



I am sensitive to PWM and have never noticed any effect what so ever with my H600 MKIII's. I am not saying that you don't, but it is quite common for people that are worried about or looking for a problem to have a problem. It can be psychological(and often is) and I would not read too much into it or say it is proof of anything. There is plenty of research on this phenomenon. Plus, a lot more then the way a light is driven can have an effect on a person. To do a true scientific test, you would have to be using the exact same emitter(literally swapping it between drivers) at an identical output. And, it would have to be on a number of different people that didn't know what the test is about. 

I think a lot of you guys stress and obsess about things too much. They are just flashlights guys lol. I try not to buy lights with visible PWM as well but, you have to realize a bit of pulsing or high frequency PWM is not going to harm you and you are already exposed to it, many times a day, every day of your life. The monitor or cell phone you are currently looking at is flickering, as is your TV. Almost every LED household bulb on the market has PWM or flicker. As does all the new street lights. Even the Christmas lights all over town right now use PWM or flicker of some kind. Billboards and digital signs too. You pretty much cannot not be exposed to it unless you live in a cabin in the woods lit by candles and use no modern technology.


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## chillinn (Dec 24, 2016)

I think a stranger and definitely existent phenomenon, compared to your proposed phantom PWM-related illness (which prior to your post I have never heard of), is the PWM-apologies that keep showing up from the "I don't care"-crowd, following the forms of "it doesn't matter," "it's not a big deal," "you're blowing it out of proportion," and the like. Considering that one camp that doesn't care about PWM, they tend to spend more posts than one would think trying to mitigate it as a problem that is only a problem if you let it be a problem.

IMO, if a flashlight is a premium quality flashlight, if it is attempting to compete in a best of the best category, and its driver uses PWM incidently and not because it must, then that is a clear deficit in the design and diminishes the notion of "premium." The manufacturer is cutting corners for a negligible increase in profit. I find it to be nothing less than cognative dissonance that a flashaholic could be more attracted to all the quality details, and then leave one the most important as a "I don't care." So they'd require a glass lens, o-rings for water tight seal, a host milled to perfection with exquisite threading, of a certain specifically sought-after material and type of anodizing, a click switch of such and such quality, an emitter that has certain aspects... but in the end completely ignore that the driver is cheap crap, and then try to promote the idea that "PWM doesn't matter." The idea that this occurs, and occurs over and over, is absurd. Why would you want a flashlight that is nearly perfect, and then have the imperfect part be the driver, of all things? Its like buying a luxury or performance car with all the exquisite trappings, and then saying "I don't care" that the tires have no tread... car still goes and is really nice... but it isn't really perfected... they cheaped out on the tires.


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## nbp (Dec 25, 2016)

I guess then I'm sure glad I cannot perceive PWM, because for me that nearly perfect light actually is perfect. 

I've had many lights and I have never been able to detect PWM in any of them. Finally something I'm good at!

Edit to add: I'm just being funny here, not picking a fight.


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## Connor (Dec 25, 2016)

Some _real _i.e. scientific information on the matter: http://webvision.med.utah.edu/book/part-viii-gabac-receptors/temporal-resolution/

I stand by my earlier opinion: if the pulsing frequency is high enough (likely somewhere in the 10 kHz - 100 kHz range), humans are physically unable to perceive it. The chemistry in our retinas needs time to "refresh" before it's able to see the next light pulse. 
When the light source/image does not move most of us can't even see 60 Hz.


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## jon_slider (Dec 25, 2016)

Gentlemen, this thread really is not intended to discuss, argue, or even educate, on the importance, value, merit, dangers or other personal preferences about PWM. It is really only intended to list lights that use Constant Current.

If PWM bothers you or not, if your reasons for caring or not caring about PWM are valid, or not, is NOT the purpose of this thread.

I have gotten too caught up explaining Why I Care about PWM. Im not going to do that any more. Im going to respect that people who do not care about PWM have their reasons, and Im not going to try and convince anyone they are wrong or should change their mind. 

Similarly, please respect those of us to Do Care about PWM for our own Personal reasons. No need to attack each other personally, for having differences in our personal preferences.

I Choose not to buy lights with PWM. I have a few reasons I wont argue about. If someone Chooses to buy lights with PWM, I respect their choice too.

Please dont use this thread to argue the pros and cons of PWM. There is a Sticky about PWM where all those issues could be discussed.

This thread is only about listing lights that use Constant Current. Not about our opinions regarding whether PWM matters to one person and not to another.

Please, dont shoot the messenger. Merry Xmas!


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## rookiedaddy (Jan 12, 2017)

@jon_slider, my sincere apology for causing so much negativity with the photo I shared... and referring to one member's post here, it's captured using cheap (phone) camera... 
so, for full disclosure (actually it's available with the image's metadata -- exif info), I'm using Samsung S7 Edge's camera to capture that image... below is the image again... all TIP in med mode...





NitecoreStore has already posted that these "wave lines" are not PWM, so let's leave it at that.
I'd captured the same "wave lines" at high mode too, which may cause disbelief to some, but let's leave it at that too.

now that I have some free time on hand, I have decided to try capturing the "wave lines" using another "cheapo camera" -- Sony RX100 video mode, and varied the shutter speed variable from 1/10 to 1/2000, as the video is posted in *Full HD*, please watch it in *Full HD* mode to appreciate the full glory of the waves... 

again, please be reminded to watch it in *Full HD mode... *

for what it's worth, unlike some light that "truly" uses PWM (e.g. the old Fenix LD05 Penlight, which happens to be the worst Fenix flashlight I ever purchased), I cannot detect the "wave lines" of these TIP in all modes in usage...


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## jon_slider (Jan 12, 2017)

thank you
I took a screenshot of the video


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## Mr. Tone (Jan 13, 2017)

I saw a post in this thread that mentioned the new 2017 Streamlights are not using PWM. Is this really true and confirmed? I really like Streamlight's designs and have used several on duty in the past. However, the PWM on the lower modes was very noticeable and drove me nuts. It was obviously a very low frequency, because it really was noticeable with even slight movement. The models I was using were probably made 2012 to 2014.


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## jon_slider (Jan 20, 2017)

Added Manker LAD (not pure PWM, also imo not pure Constant Current)


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## ElectronGuru (Jan 20, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

FYI
Oveready / TorchLAB v5 are constant current. This includes both Wasp and BOSS.

Elzetta may also be non pwm. Many configurations are single level heads + two mode resistor in the tail cap.


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## jon_slider (Jan 23, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



ElectronGuru said:


> FYI
> Oveready / TorchLAB v5 are constant current. This includes both Wasp and BOSS.
> 
> Elzetta may also be non pwm. Many configurations are single level heads + two mode resistor in the tail cap.



thank you. I agree that single mode lights, and 2 mode resistor lights, do not use PWM.

where did you get the info about the Boss and Wasp? have you tested those lights with a camera?

fwiw, Manker Lad, Nitecore Tip, and Zebralight, all claim to use NoPWM, but they are also not constant current, and this can be demonstrated by the presence of scan lines in photos I have posted.

fwiw, Zebralights do not use PWM, but they use pulses. I do not consider Zebralight a Constant Current light.

Here is a photo of Low1 on an SC52 (photo from Samsung Galaxy S7)


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## nbp (Jan 23, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

EG is part of the team that MAKES the BOSS and Wasp, so he knows a lot about the design of the light engine.


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## jon_slider (Jan 23, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



nbp said:


> EG is part of the team that MAKES the BOSS and Wasp, so he knows a lot about the design of the light engine.



good to know, thanks

Then this might be a great opportunity to hear whether the light uses any type of pulses, even pulses that do not drop to zero, and are technically not PWM, but also not Constant Current. HDS for example uses a hybrid system that is neither PWM, nor constant Current, so does Zebralight.

Many manufacturers report their lights are NoPWM, Zebralight, Eagletac, Tip, LAD, yet the lights still use pulses that produce scan lines in photos.

I just bought a LAD on the manufacturers say so that it has no PWM, and technically it does not, but it does use pulses. Here is a photo of the Manker techically not PWM. I think we could at least all agree that this photo does not show a Constant Current light.





The manufacturer of Zebralight also claims their lights use no PWM, which technically is correct, but as you can see in the photo, Zebras also do not seem to use Constant Current:





Im guilty of using a broader definition of the term PWM, to include pulses that dont drop to zero, but are not constant current. fwiw, Zebralight insists their light IS constant current.. so maybe Im just confused about the technical terms, but the photo tells the story.


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## jon_slider (Jan 25, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Added Oveready Boss

extreme closeup photo I requested, courtesy of run4jc. no "circuit noise" of any kind.. Outstanding Flashlight imo!


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## jon_slider (Jan 27, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Added Astrolux M01 and M03


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## Lex Icon (Apr 8, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Never having noticed any PWM on my MecArmy PT-18, I found this review and photo on another forum claiming lack of PWM.
http://forum.fonarevka.ru/showthread.php?t=31563


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## ssanasisredna (Apr 9, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Constant current does NOT mean no ripple (or pulsing or whatever term you want to use). It just means a regulated average current.

Zebralight IS constant current. It is likely (but not a given) that their regulation scheme uses something called peak mode current control, and how they have sized the components, likely for cost, size, efficiency, has some ripple at the switching frequency.


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## jon_slider (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



ssanasisredna said:


> Constant current does NOT mean no ripple (or pulsing or whatever term you want to use).



thanks for the education
so, what do you call it when a light shows interference in a photo, and why does Zebra show blurry dots, and why does maukka report it as PWM(Zebra on far left)






also, why does Tip and Lad claim constant current, yet they produce these effects in a photo:





Manker Lad





Lastly, here is a Lumintop Copper Worm, which also claims Constant Current, like Zebra, Tip, and Lad. Why does the Worm show no photo interference and the others do?:


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## scs (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

jon, I might have missed mention of the Olight S1A. I have it and can't detect PWM using all the layman's test: shower, fan, and camera. Consider including it in the list?


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## Tachead (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



scs said:


> jon, I might have missed mention of the Olight S1A. I have it and can't detect PWM using all the layman's test: shower, fan, and camera. Consider including it in the list?


Did you try the tests on the moonlight mode? The S1, S1R, Smini, H1, and H1R all have PWM but, only on their moonlight modes. Considering the S1A is basically an AA powered version of those lights, I would guess it does as well.


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## scs (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



Tachead said:


> Did you try the tests on the moonlight mode? The S1, S1R, H1, and H1R all have PWM but, only on their moonlight modes. Considering the S1A is basically an AA powered version of those lights, I would guess it does as well.



Yup.


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## scs (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

jon, how's this review: http://www.candlepowerforums.com/vb...1A-amp-S2A-(TIR-Optic-XM-L2-1xAA-2xAA)-Review


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## Tachead (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



scs said:


> Yup.



Interesting. We would need an oscilloscope reading to know for sure though. If so, too bad they didn't follow suit with all the other models. Although they use a high enough frequency that it doesn't matter much in practice anyway.


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## maukka (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

No PWM on the S1A on any battery (AA NiMH, AA Lithium, 14500 LiIon).


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## jon_slider (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



scs said:


> jon, how's this review: http://www.candlepowerforums.com/vb...1A-amp-S2A-(TIR-Optic-XM-L2-1xAA-2xAA)-Review





maukka said:


> No PWM on the S1A on any battery (AA NiMH, AA Lithium, 14500 LiIon).



thank you both!
added to page 1


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## scs (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Also, Jon. It's been a long while since anyone has done a thorough review on any of the Armytek lights. I believe all current Armytek models are CC without PWM. Be great if someone could confirm or show otherwise.

I have a Prime A1 Warm v2, I think, a first batch Wizard Pro XHP50 warm, a 2nd batch Dobermann Pro XP-L HI white. None has visible PWM based on previously mentioned tests. I'm not aware of any formal review that supports my observations though.


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## Woods Walker (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



scs said:


> Also, Jon. It's been a long while since anyone has done a thorough review on any of the Armytek lights. I believe all current Armytek models are CC without PWM. Be great if someone could confirm or show otherwise.
> 
> I have a Prime A1 Warm v2, I think, a first batch Wizard Pro XHP50 warm, a 2nd batch Dobermann Pro XP-L HI white. None has visible PWM based on previously mentioned tests. I'm not aware of any formal review that supports my observations though.


I could do a cellphone camera test on a bunch if anyone is interested. Cellphone camera
is really good at detecting any discepancy IMHO.


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## scs (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



Woods Walker said:


> I could do a cellphone camera test on a bunch if anyone is interested. Cellphone camera
> is really good at detecting any discepancy IMHO.



WW, I used a cellphone camera as well, but please test your newer samples.


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## Woods Walker (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Ok I can test a V3 plastic harness not pro wizard and V3 Pro Viking. Both XP-L Out
of curiosity will check the others as well. Tonight I am going on a night run so it will be late.


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## Tachead (Apr 10, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Armytek Tiara Pro V2 XP-L(Warm), Viking Pro V3 XP-L(Warm), and Prime Pro V3 XHP-35(Warm) have no PWM or flicker on any mode that I can detect.


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## jon_slider (Apr 11, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



Tachead said:


> no PWM or flicker on any mode that I can detect.


thanks, if you post some closeup photos of the LED I will link to your pics and add them to the first post


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## Pinarello (May 11, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Didn't see any review for the modders lights. Does, for example, Tana, Pflexpro, Adventure Sport..use PWM? They are "top"lights and pricey too, so I would be glad to know more about them. Also, Muyshondt lights are fantastic in every sense, but..are they PWM or CC?
Very grateful for enlightened me in the matter.
"Long as I can see the light"


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## scs (May 11, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



Pinarello said:


> Didn't see any review for the modders lights. Does, for example, Tana, Pflexpro, Adventure Sport..use PWM? They are "top"lights and pricey too, so I would be glad to know more about them. Also, Muyshondt lights are fantastic in every sense, but..are they PWM or CC?
> Very grateful for enlightened me in the matter.
> "Long as I can see the light"



Pflexpro uses linear drivers with 7135 chips.
Listed as CC but with PWM in the high kHz range.
Somehow CC does NOT mean no PWM so beware of that as well.


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## scs (May 11, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Others please correct me if I'm wrong. Is it safe to say that all linear drivers or drivers that use 7315 chips use PWM?


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## jon_slider (May 11, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

I do not know the answers to the questions about unlisted lights, driver types, etc
I try to list lights as I receive info on them, from people posting here, and in other threads

if you have a light that you think belongs on this list, post it, with some evidence

Constant Current can also have feedback loops that create brightness fluctuations, and show up in photos as interference. It is not technically PWM, but it can interfere with photos.

Zebralight, correctly claims to use Constant Current, and correctly claims to not use PWM, yet their lights still produce changes in brightness that can be measured on a strobe and can be detected with a cell phone camera, although it is almost undetectable when waving the light. I call Zebralight powermanagement a form of hybrid PWM, but technically it is a feedback loop in a constant current circuit. I have listed Zebralight in both the yesPWM and the NoPWM threads, with this explanation.


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## scs (May 11, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*



KITROBASKIN said:


> Please specify what is "Listed as CC...". PFlexPRO is one of the very few makers who details the nature of their engines. Some light levels are called direct drive, most modes use PWM, stating the frequency as well. I can't detect the high rate of pulse of any kind with my PFlexpro and do not consider phone camera images meaningful.



Select any of the dropins, click on the Technical Specs tab. It says "constant current" and below lists the PWM frequency.


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## Arizona_Mike (May 11, 2017)

Keep in mind that all efficient DC-to-DC regulation is high frequency PWM (which gets integrated/rectified). Rectification can be done by capacitor, stray capacitance of the LED junction, or your retina 

Linear regulation (voltage or current) involves running a gate of some kind (usually a MOSFET) in its liner range. Transistors don't consume much power fully on or fully off. When partially on they emulate a variable resistor and consume power (and add more battery drain and flashlight head heat). The larger the voltage difference the more inefficient linear regulation becomes.

Mike


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## 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 on the List of lights with PWM or Pulsed circuitry. I personally am very disappointed, as I was tempted to buy a new High CRI Zebra, but I do not consider it to be a true NoPWM, NoPulsed power circuit..


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## ssanasisredna (May 30, 2017)

-----


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## TCY (May 30, 2017)

jon_slider said:


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



I'm confused, as I remember selfbuilt's reviews claiming that all the ZL lights he tested have no PWM.

From selfbuilt's Zebralight SC600-III (XHP35, 1x18650) Review:
"As with my other Zebralight lights, I don't see any signs of pulse width modulation (PWM) on any the lower output modes. The light appears to be fully current controlled at all levels."


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## jon_slider (May 30, 2017)

TCY said:


> I'm confused


there is a lot more detail available if you read the other posts in this thread
selfbuilt and maukka have different perspectives and test instruments

it may also help you to read this, and this


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## TCY (May 30, 2017)

jon_slider said:


> there is a lot more detail available if you read the other posts in this thread
> selfbuilt and maukka have different perspectives and test instruments
> 
> it may also help you to read this, and this



Thanks. I remember asking ZL about PWM when I saw this thread, I got their reply and totally forgot about this whole thing exists.

Here's their reply from 16/11/2016:
"_Constant current regulators always use a feed back circuitry to measure the output current (that passes through the LED) and adjust the supplying power (up and down) to the LED accordingly. The action itself has (up and down) ripples. Good circuitry designs usually make the ripples so minuscule and/or fast enough, relative to the LED output, that they won't be seen by human eyes. You'll need a digital camera with a global shutter (rather than a typical rolling shutter) or a traditional film camera to detect flashlight PWMs properly._"

So according to them the current ripple is supposed to be there if a constant current regulator is used.


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## sbslider (Jun 18, 2017)

I nominate the manker e02 based on the manufacturer's website and the pictures above.

A couple more requested images.


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## Pinarello (Jul 1, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

Missing Surefires! What about their range of lights? I think many of us would appreciate SF testing on PWM


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## jon_slider (Jul 1, 2017)

*Re: List Lights that use NO PWM, nor pulses, and are true Constant Current*

#107


Pinarello said:


> Missing Surefires! What about their range of lights? I think many of us would appreciate SF testing on PWM



feel free to post any tests you do, include a photo please

Im just a consumer, nobody gives me free samples, but if you want to send me some lights, feel free 

I post lights that I research out of personal interest, and anyone can post their own tests from their personal interests.

you can also google surefire flashlight PWM by clicking here
or add the specific model name to your search for more accurate info.


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## ank (Oct 29, 2017)

Acebeam K70


















Doesn't seem to use PWM but there's a strange hissing sound on the highest mode


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## ank (Oct 29, 2017)

Acebeam K70


















Doesn't seem to use PWM but there's a strange hissing sound on the highest mode


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## jon_slider (Oct 29, 2017)

thanks for contributing ank, 
selfbuilt agrees with you that the K70 does not use PWM
the whine is a known behavior, mentioned here but is not PWM caused.


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## RCS1300 (Apr 7, 2018)

jon_slider said:


> this thread is not meant to debate whether PWM matters or not. And Im not recommending for or against PWM. Im just trying to list lights in this thread that do NOT use PWM. Basically, just the Facts.



Jon, unless you can prove otherwise I believe that virtually ALL LED flashlights that change brightness levels use PWM. I believe the standard for determining whether a flashlight design is good or bad regarding PWM is whether one can see the pulses with an unaided human eye.

The two threads you have going on this subject that categorize flashlights on PWM is very likely doing a disservice to the flashlight community as you are not categorizing these lights by whether one can see the PWM with the unaided human eye. 

I could see going forward with these threads if, for each flashlight on one of these lists, you took a poll of 25 owners and users to determine whether or not they notice PWM with their unaided human eye. Otherwise, in my opinion, these lists are inaccurate and misleading and should be removed from the perceived endorsement of CPF.


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## Modernflame (Apr 7, 2018)

Forgive me if this has already been stated somewhere on this thread, but I thought some clarification would be in order. Regarding Malkoff flashlights, the multimode MDC products use PWM. However, the other devices do not, as they are either single output devices or they achieve low beam by means of a resistor (i.e. current regulation).

The following Malkoff devices do not use PWM:

MDC SHO
Single mode E1, E2 variants
Maglite upgrades
M31 variants
M61 variants
M91 variants
Wild Cat
Hound Dog 18650
Hound Dog XML
Hound Dog Super


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## DavidRZ (Apr 11, 2018)

RCS1300 said:


> Jon, unless you can prove otherwise I believe that virtually ALL LED flashlights that change brightness levels use PWM. I believe the standard for determining whether a flashlight design is good or bad regarding PWM is whether one can see the pulses with an unaided human eye.
> 
> The two threads you have going on this subject that categorize flashlights on PWM is very likely doing a disservice to the flashlight community as you are not categorizing these lights by whether one can see the PWM with the unaided human eye.
> 
> I could see going forward with these threads if, for each flashlight on one of these lists, you took a poll of 25 owners and users to determine whether or not they notice PWM with their unaided human eye. Otherwise, in my opinion, these lists are inaccurate and misleading and should be removed from the perceived endorsement of CPF.



Agreed!


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## parametrek (Apr 11, 2018)

RCS1300 said:


> Jon, unless you can prove otherwise I believe that virtually ALL LED flashlights that change brightness levels use PWM.



What do you consider sufficient proof to change your mind? What amount is "virtually ALL" anyway? Are you counting by flashlights made or by product lines? If you are counting individual flashlights sold then maybe the majority of lights use PWM but <i>only because of the millions of SK68</i> flashlights out there. If you are counting product lines do all of the numerous fly-by-night chinese clones count as a single product or a hundred?

Constant current is not difficult to do. Extremely cheap lights will use a resistor or direct drive. Slightly nicer lights will use an AMC7135. Still nicer lights will use a buck or boost regulator. Single mode lights of course have no reason to use PWM and there are still a lot of single mode lights out there.

Of course nearly all of the extremely inexpensive generic multimode chinese lights will use PWM. You get what you pay for. But we as a community don't really care about those lights except as modding hosts.



> I believe the standard for determining whether a flashlight design is good or bad regarding PWM is whether one can see the pulses with an unaided human eye.



This thread isn't about passing a good or bad judgment. Using PWM is a technical aspect. Either a light does use it for some modes or does not. I don't agree with everything about Jon's methodology but it is close enough most of the time. (Not everyone can use the dictionary definition of PWM or spend $30 to put together a system to accurately measure PWM.)



> The two threads you have going on this subject that categorize flashlights on PWM is very likely doing a disservice to the flashlight community as you are not categorizing these lights by whether one can see the PWM with the unaided human eye.



So? If it shows up on a camera then it means that I can't use the light for taking pictures. That is unacceptable. I completely disagree with his assessment of Zebralight but I wouldn't consider him to be doing a "disservice."



> I could see going forward with these threads if, for each flashlight on one of these lists, you took a poll of 25 owners and users to determine whether or not they notice PWM with their unaided human eye. Otherwise, in my opinion, these lists are inaccurate and misleading and should be removed from the perceived endorsement of CPF.



How does someone on the internet saying something come across as endorsement of CPF? But who am I to argue with David Martin, mayor of Stamford Connecticut. As a resident your statements are the perceived endorsement of the entire city and its governing body.

The majority of serious flashlight manufacturers don't use PWM of any kind according to their own statements. The majority of flashlights that I've bought don't use PWM. All of my lights that claim to not use PWM (90% of them) really don't have any PWM observable by eye or camera or meter.

On a related question, should I add a PWM field to my database of flashlights? It would be a LOT of work to go back and add it to the existing 1900 lights but if people feel strongly enough about it I'll do it


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## sbslider (Apr 11, 2018)

x2 to what parametric said


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## RCS1300 (Apr 11, 2018)

parametrek said:


> Constant current is not difficult to do. Extremely cheap lights will use a resistor or direct drive. Slightly nicer lights will use an AMC7135. Still nicer lights will use a buck or boost regulator.
> 
> Of course nearly all of the extremely inexpensive generic multimode chinese lights will use PWM. You get what you pay for.






parametrek said:


> This thread isn't about passing a good or bad judgment.



In the first statement above, you just did!

Many people that want to learn about flashlights, especially before purchasing one, come to this site looking for informed information and opinions. I do. What I found are these two lists that cast doubt on the value of $400 flashlights, not inexpensive Chinese lights. And, the information on these lists was not correct!

If one wants a flashlight for photography one knows in advance that the camera slows down action and as a result, your needs are different than if one is purchasing a flashlight for personal use with the unaided eye.

These lists would be more meaningful for people considering a flashlight purchase if the lists were based on surveys of 25 CURRENT real owners and users per light on the list to confirm PWM exists or does not with the unaided eye.


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## User 0815 (Apr 12, 2018)

Would like to add two lights to the List:

1st. Manker T01 II NW, tested in front of oscilloscope with led - no sign exept the DS0201 itself (the force is strong in this device, see ripple on display.)




Sorry, no pic of DSO itself - due to not saving to card. None of mine.

2nd. Sunwayman V11R révolution NW
same curly line of DSO. Pic of evidence must be given later - battery went down  Of course not the one in the light, the one in the camera.

Regards Peer


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