PWM - What is it, How does it work and how to detect it.

[reppans]

Thank you! I ran into the dark bathroom waving half of my lights right after reading. My girlfriend was very confused.

JMHO, but I wouldn't go looking for it :shrug:.

http://www.candlepowerforums.com/vb...to-detect-it&p=4307784&viewfull=1#post4307784

 

[Cataract]

LOL, but it's a great method to find a way to improve one's collection

 

[feifei]

well done, thanks for sharing the post,I have no idea about this,but have learnt a lot after reading the post.

 

[Cataract]

Thank you, it is really my pleasure to share the knowledge.

 

[BrianHook]

Nice work, I must say. Various points discussed here about LED flashlights are genuinely very informative.

 

[Cataract]

Thank you sir.

 

[whiterabbit05]

Thank you. I found this very useful when recently purchasing a Streamlight Protac HL and seeing PWM being mentioned in reviews of the light's low mode.

 

[Cataract]

Kinda sucks that Streamlight would go the PWM way. Were you able to detect it? Is it really annoying?

 

[franksr]

As a newbie to both LED lights and this forum I much appreciate your description of PWM as it has enlightened me and cleared up a few questions I had regarding PWM.

 

[Cataract]

As a newbie to both LED lights and this forum I much appreciate your description of PWM as it has enlightened me and cleared up a few questions I had regarding PWM.

Thank you. There's nothing like knowing my article did what it was intended to

 

[RI Chevy]

This thread was one of the more informative and useful on this forum! :thumbsup:

 

[Cataract]

Whoa! Thanks a million! I definitely didn't expect that one

 

[Neosec]

Great job Cataract!!! :thumbsup:

Very well done and the photos really make the point.

One thing I'll note that has changed (which doesn't matter much for the content of this topic) that you may or may not be aware of, you said:

PWM is mainly used to control electric motors (like hybrid cars), but mostly step-motors like the ones in your hard-drive.

Hard drives (all?) no longer use stepper motors. The spindle motor is DC same as it's been and the armature motor is now a voice coil motor. Much faster.

Again, Great post!


Neo

 

[Cataract]

:thanks: AND :welcome:

Good to know about hard drives, I haven't been following computer technology evolution for a long while.

 

[Mr. Tone]

Kinda sucks that Streamlight would go the PWM way. Were you able to detect it? Is it really annoying?

My Streamlight has noticeable PWM on the medium and low modes.

 

[Cataract]

My Streamlight has noticeable PWM on the medium and low modes.

Bummer. Thanks for sharing

 

[RI Chevy]

My Streamlight has noticeable PWM on the medium and low modes.

Does it have the whine on the low modes as well? Or just the visual PWM? I really hate PWM! I am a digital linear kinda guy!

 

[Mr. Tone]

Does it have the whine on the low modes as well? Or just the visual PWM? I really hate PWM! I am a digital linear kinda guy!

I don't hear anything but it is visually obvious. That is an unfortunate design for an otherwise great LEO light.

 

[bpierce]

Great post. One question: is a circuit that supports higher frequency PWM more expensive to manufacture? Wondering why anybody would go with the lower frequency variety except maybe for cost reasons.

 

[jorn]

Some years ago i read that low frequency is more efficient. So i guess thats why. Dont know for sure, so dont quote me on that ;-)