List Lights that use NO PWM

[rookiedaddy]

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...

 

[WarriorOfLight]

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.

 

[vadimax]

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...

 

[WarriorOfLight]

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.

 

[LeanBurn]

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

 

[Lexel]

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

 

[Lexel]

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...

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

 

[jon_slider]

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.

 

[Lexel]

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

 

[rookiedaddy]

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
...

Thank you for the detail explanations. :twothumbs

 

[NitecoreStore]

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?

 

[jon_slider]

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

"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."

 

[chillinn]

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.

 

[ven]

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

 

[chillinn]

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.

 

[chillinn]

duplicate
.
.

 

[jon_slider]

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.

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

 

[chillinn]

"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.

 

[TheBelgian]

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.

 

[jon_slider]

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