PWM on Solarforce L2P

I am learning about PWM on flashlights. Then I tried to test most of the lights that I have with the live view LCD monitor of the video camera, and also with the fan. I discovered that my L2P (R5 - 5 modes) has a very significant PWM on low and medium mode.

Does anybody know what is the frequency of the PWMs in L2P? or how to measure them? Thanks in advance.

Measure with a scope, but before you do ask yourself why. If you need fans and monitors to find out it even has PWM it obviously doesn't bother you so if i were you i'd just let it be.

RepProdigious, you are right. I am just curious about it. But by the way, what is the scope and how to measure? Thanks.

phonoe said:

RepProdigious, you are right. I am just curious about it. But by the way, what is the scope and how to measure? Thanks.

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Oscilloscope, its a big and quite expensive piece of machinery and if you have never heard about one im pretty sure that's not the way to go for you. An easier way would be to check what components the driver board has and go from there.

If the frequency of PWM is 100hz or higher you probably won't notice it. I have a Pelican 9410 and it uses PWM for the lower mode (300 lumen), I can only see it while looking at water exiting the bathroom shower head.

afdk said:

I can only see it while looking at water exiting the bathroom shower head.

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I guarantee you will never see a quote such as this, anywhere else except on this forum. From the mouths of flashaholics...

Oh dang! I just thought of the nerdiest way how you can calculate your PWM frequency:

Youll need a dark room and an assistant (or tripod) with camera. Set the camera to a nice long shutter speed and drop the flashlight from a known hight in such a way that you can see the entire drop traject whilst making the picture. With that picture you can pretty accurately calculate your PWM frequency and even duty cycle because all factors are known!

LOL, or just don't worry about it at all if you can't see it with the naked eye.

'Scopes, fans, time-lapse cameras, shower-heads - pffffff...why are we trying so hard to see something that we can't see?

Damn you Hans and Zaccharias Janssen. (Google them)

RepProdigious said:

Oh dang! I just thought of the nerdiest way how you can calculate your PWM frequency:

Youll need a dark room and an assistant (or tripod) with camera. Set the camera to a nice long shutter speed and drop the flashlight from a known hight in such a way that you can see the entire drop traject whilst making the picture. With that picture you can pretty accurately calculate your PWM frequency and even duty cycle because all factors are known!

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I don't see how that would work to calculate anything meaningful. You'd end up with a blur of light in your example. If instead of PWM it was in a moderate strobe mode with a short duty cycle, then you might get some individual beams of light.

Rather than an Oscilloscope, you could use a small handheld device called an optical tachometer. They're often sold for measuring RPM of rotors on hobby aircraft. They work by detecting changes in light intensity as the rotors spin in front of the optical element. I can't say I've ever tried this method, but it should certainly work.

So I'm not the only one to shower by the light of a flashlight? (so as not to wake the wife )

If I can see PWM while walking across the grass in the dark (a practical application, as opposed to all the others mentioned) then it's too low for me.

shane45_1911 said:

I guarantee you will never see a quote such as this, anywhere else except on this forum. From the mouths of flashaholics...

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CarpentryHero said:

So I'm not the only one to shower by the light of a flashlight? (so as not to wake the wife )

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Nope.

I use a light in the shower regularly. Not to wake the wife though... our house has one of those bloody vent fans patched into the light switch, so it's always on whenever the light is on. (I'm too lazy to do anything about it and I don't know electrical stuff too good.) So in the winter time, I freeze my keister off gettin out of the shower if the fan is running. So I just use one of my lights so I can keep the fan off, and then everything is toasty warm from the steam when I get out to dry off.

Remove the grille from the fan. Inside you'll see a two prong plug, just like on a table lamp cord; unplug it.