Constant Current incan modes. Why not?!!?

chillinn

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Went off the topic in another thread. Starting here fresh. I think this deserves examination.

Naive and young for my age, I was seduced by Computer Science. FYI, CS has nothing whatsoever to do with computers. The "computer" in "Computer Science" is in fact a person, i.e. one who computes, or one who reckons. They should have called it "Reckoning Science." Only when it was too late did I discover that Electronic Engineering was a thing. That was what I should have studied.

Unfortunately there's no such thing as current controlled Incan. They're controlled by voltage and pwm.

I see this repeated, that incan can't do CC.

What I want to know is not if "there are no CC incans," but if it is absolutely logically and physically impossible in this Universe for incan to do CC, or if it is rather the case simply that no one has yet attempted, or no one clever enough has come along to create it. Aren't there three mode lightbulbs? Aren't they CC? Isn't the round fader on my mother's dining room chandelier CC? Why not an incan flashlight? If it is impossible, there are likely good reasons. But if it is merely difficult, then a little elbow grease, ingenuity, and perseverance could bring this into the world. So which is it? Impossible? Or merely difficult, and so far has not been attempted?

Let's try to avoid discussing or promoting the idea that PWM incan modes don't suck. PWM sucks, period, and it doesn't matter if you personally don't mind it. That it doesn't bother you personally is in no way a positive argument for PWM, but instead that is merely a positive argument for apathy. Also, even if something cannot be seen or detected does not eliminate the possibility that it can harm you or others. PWM is harmful to me, even when I can't visually detect it. So I want to head off at the pass those that are prodigiously loyal to their favorite flashlights despite the fact that they utilize PWM.

I really appreciate the sharing of knowledge by those that understand the stuff I don't. Thanks.
 
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chillinn

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Well, it would be even more awesome to have an incandescent flashlight with modes that is regulated for constant brightness and is also a constant current circuit. And while we're at it, let's add a low voltage cut off to protect the cell and the user. I can't imagine that anyone that appreciates incan would be opposed to the idea.
 
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bykfixer

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If it could be done PK or Pentagon probably did at some point.

Matter of fact I do remember PK talking to Scout24 about why one of the SureFire switches wouldn't work on his PR-1 due to the switch being hi/lo. That was somewhere in the PKDL thread. Then the other day I saw where Pentagon had a hi/lo tape switch on the MD2 or something... It was one of their weapon lights.

So yeah I think it can be repeated, but is there enough demand?
 
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chillinn

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Demand is irrelevant, imo, just like the height of a mountain is irrelevant to the reasons for climbing it. My intention is not to evoke a resurgence in market demand for incandescent flashlights (though this would not bother me in the least). But if the design and creation of such a modern driver for incan is not unfeasable economically for a dozen or a hundred to be produced and funded by the rarer incan consumer, that it should be attempted and completed simply because it can be done. Such a rare batch would have inherent value, and it's market value would increase with age, assuming MagLite or any other brand still manufacturing incan flashlights didn't pick up the idea and mass produce it (which, again, would not bother me in the least).

Also, not for nothing, I have already been shot down and educated in another thread regarding a McE2S-style hi/lo switch for incan in another thread. I confess I exaggerated a bit there. The truth is I had won an auction for an E2E with incan head that advertised it came with a hi/lo switch, and made the poor assumption that it would work. When the light arrived, I discovered it was not a hi/lo switch, but probably a McClicky, and the seller made an honest mistake. The seller never got back to me, but being that the deal was still a great bargain, I'm not going to complain or pursue it.

Still it makes me wonder if it could possibly be as simple replacing the resistor in a hi/lo switch with some other kind of electrical doodad to make an incan hi/lo switch viable and operable for a couple incan modes. But I don't know what I am talking about. ><
 
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vicv

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Another great part about constant current is it would also provide soft start. Now constant current is actually voltage controlled. An led's VF changes as it's temperature increases which is why it can't be controlled by voltage regulation. Also an led will increase its current exponentially from a small increase in voltage. An Incan bulbs current draw rises evenly with voltage. The reason why we don't have current controlled Incans is the same reason we don't have voltage controlled ones. Lowering the voltage for a lower output cause a big tint and efficiency shift in the wrong direction. Most people don't want that. So modes are out. You could have a voltage regulated circuit for one mode but most seem.to be pwm. A simple DC DC switching regulator. No idea why pwm is always used. The circuit would use pwm on the source side and filter it to get a constant DC output to the bulb. It's easier to rapidly turn a fet on and off I guess.
Your dimmer in your house uses a potentiometer to lower the voltage to the bulb to dim it. For a 120v bulb tint shift will not be too sever. For a bulb under 10V it will which is why it's not used for modes on a flashlight. Also as the cells drain it would get worse and worse and you'd just be wasting the extra voltage as heat
Those 3 mode light bulbs contain 3 different elements inside
 
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chillinn

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It would be pointless, I suppose, to have a multi-mode incan where the lower modes did not stretch the battery capacity. I hope this is not the only possibility if designing CC for incan.
 

vicv

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It would stretch the runtime a bit but not as much as pwm does. Did you try the 9v bulb on a single cr123 or 2xaa like I suggested in the other thread? That's how a dimmed Incan on anything other than pwm will look.
 
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chillinn

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It would stretch the runtime a bit but not as much as pwm does. Did you try the 9v bulb on a single cr123 or 2xaa like I suggested in the other thread? That's how a dimmed Incan on anything other than pwm will look.

I did not try, though I take your word for it. Have you ever tried lighting your room with candles? I would not mind burning candles, but for the soot it puts into the closed atmosphere of a room and the inherent danger of an open flame. I don't mind tint shift at low modes. I love the colors of dawn, and I love an orange-red sunset (either golden hour is exquisite). I like the ambiance of that color. With dark adapted eyes, poor yellowy tint from an incan filament is not intolerable and in fact it can be rather romantic. In fact, I have full intention of having Vinh fix me up an LED flashlight with an amber X-PE. Amber is a good color for outdoors, espescially here in Florida, where there are a gazillion light-attracted flying insects per resident. vivc, I realize that it might be obvious to you, but you never detailed any reasons why you couldn't tolerate or enjoy yellowy incan... feel free to bash it, but what are your personal reasons for despising it?
 
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vicv

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Oh I love incans and I love the tint. I do prefer overdriven ones but one of my most used light is my maglites solitaire and it's quite yellow and weak. Reasons why I like it. So when I tell you that light will look like a cool led compared to what you're asking for is what I'm talking about. Not just an under driven incan but a badly underdriven one. Ten times worse than a maglites on dead cells. That's why no one makes current controlled modes with incan lights
 

chillinn

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Back to the fader on my mom's chandelier... I know others have done this. When you turn the fader to the point where the light is almost off, and the filiment is barely producing any light. idky, I love looking at those badly underdriven lamps.

That said, little compares to a properly overdriven incan lamp.

That's why no one makes current controlled modes with incan lights

So is this the answer to my OP query? That a multi-mode CC incan driver is neither logically nor physically impossible, but instead it is impractical? If so, the follow-up question is "can the impractibility of a multi-mode CC incan driver be mitigated, either through trial and error or the brilliance of epiphany?"
 
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ma tumba

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Great thread!

And regardless of the answer to the original question I think that it would be great to have a regulated switch for incands, kind of aw type, but with regulated output. And compatible with smaller size tail caps, like that of a e2e.
 

chillinn

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Great thread!

And regardless of the answer to the original question I think that it would be great to have a regulated switch for incands, kind of aw type, but with regulated output. And compatible with smaller size tail caps, like that of a e2e.

AW's switch uses PWM. Get an incan A2 Aviator; has 2 modes, it is regulated and has constant brightness, though it is not thread-compatible with E-series. Tad Customs has a bipin socket available for A2 as well.
 

chillinn

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The a2 also used pwm

Yup, but it does have regulated output, and it is easier to come by than AW's switch replacement. But I suppose an even easier item to find, if unphased by PWM, is the LightSaver Miser tailcap for E-series, though it is not regulated for constant brightness.
 
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ma tumba

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I had no idea that someting like Light Saver existed for e-series lights. Will definitely try that offer from the bay.

Now, your issues with pwm, especially with that in the Lightsaver is an interesting case. I am very sensitive to any sort of flickering, like that in luminiscent lamps, CRT monitors etc. Having said that I have never had any issues with incand, including a2, aw 3-stage switch. So may I ask a few questions about your experience?

1. With the lightsaver, do you have the issues at all 3 levels, including the 100%, and are these issues equally bad for all levels?
2. Do you have any issues with traditional incand bulbs, fed by 60Hz mains?
3. Can the issues be associated with the sound, generated by PWM in the Lightsaver, rather than the light pulsations? Some people (including myself) just cant stand it even below the hearing threshold.

Now, regarding your (and my own) quest for ultra warm dim incand light. The best thing that I have found is a 2xaa maglite with a SF F04 diffuser. MiniMag is also a 1 inch light so F04 fits like a glove. The great thing about this setup is that it is effectively a multi-mode light. When you switch the light on you have a wall of light at about 15lm. When you unscrew the head further you have kind of more concentrated but still very diffuse hot spot. But when you unscrew the head even further you get, again, that wall of light which is much dimmer because a lot of lumens are lost now inside the light. I would say, that in this mode I have about 3lm at most. I am very happy about this setup for night time indoors. And it works for a long time.
 
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chillinn

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So may I ask a few questions about your experience?

1. With the lightsaver, do you have the issues at all 3 levels, including the 100%, and are these issues equally bad for all levels?
2. Do you have any issues with traditional incand bulbs, fed by 60Hz mains?
3. Can the issues be associated with the sound, generated by PWM in the Lightsaver, rather than the light pulsations? Some people (including myself) just cant stand it even below the hearing threshold.

Certainly,

1. I can't distinguish between the levels regarding the onset of headache. First it starts with something like tenitus, and that "noise" gets louder like a wave approaching, then normal levels of headache pain, but this leads to greater levels of pain in migraine eventually, and within minutes. But I do believe even the 100% first mode has the same or closely similar effect on me, leading me to believe the LightSaver is using PWM even on it's brightest and first mode.

2. No I don't, and I am aware they are actually flickering, if fed by 60Hz mains, at 120Hz. I speculate reasons why this may be here. But it is only speculation. I am not a neurologist nor do I play one on TV. ;-)

3. Good question! I don't hear any sound from it, but rather the "sound" I hear is of a tenitus-like ~14kHz audio effect that is surely internal to me. My ears are pretty sharp, and if it was producing sound, I should be able to identify that as the source of the problem. In fact, I have subsonic hearing, and quickly can identify that diesel bus going past is what is painful, when others near me can't hear the extremely low frequencies. This is one reason why thumping subs in compact cars is silly, because most people can't hear subsonic frequencies. Also, low frequency waves are far longer than the inside of those cars, so even the thumping sub lover can't hear those frequencies inside the car, because the sound waves can't fit in there.
 

ma tumba

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Chillinn, I finally got a multiple level tail switch for maglite mini (made by nite ize, based on the same IQ circuit as the lightsaver mizer) so I can now make informed comments to what you shared.

1. There is a clear and significant flicker at 25% and 50% levels, it is not PWM because it is very low frequency (few Hertz), but it is there. To see this flicker you need to illuminate an area so you can see low surface brightness. You would't see it when you stare at the hot wire since your retina is oversaturated. In this case you don't see it but are still affected by it.

2. There is a whining sound. It is not the low freq one you mentioned, rather it is a very high pitch tone, typical for pwm. It is higher that 5kHz, so, again, the PWM at 5+ kHz has nothing to do with the flicker which is 1000 times lower in frequency.
I can hear it when the switch is very close to my ear, not more than 10cm away, so I don't think that it may have caused your problem. When I put a silicone butt over the switch the sound was completely eliminated.
 
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