Constant Current incan modes. Why not?!!?

[ssanasisredna]

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. So the result is that I know very little about electicity, having dropped out of Physics early in the second semester, just as I was introduced to Maxwell.



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.

PWMing INCAN does not product visible effects and practically, does not produce any invisible effects either. It's a hot wire. It does not cool much between PWM cycles unless you were PWMing at a really low frequency which there is really not much practical reason to do..

Even for an LED, if the PWM is high enough frequency, again, there are no invisible effects.

 

[ssanasisredna]

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

Dimmers in houses are not potentiometers, they cut the waveform which does the same thing as lower the voltage and the shift in CCT is the same for any other incandescent bulb.

 

[chillinn]

PWMing INCAN does not product visible effects and practically, does not produce any invisible effects either. It's a hot wire. It does not cool much between PWM cycles unless you were PWMing at a really low frequency which there is really not much practical reason to do..

Even for an LED, if the PWM is high enough frequency, again, there are no invisible effects.

Apologies for my dissenting opinion, but concerning incan filaments and PWM, this often repeated theory looks good and sounds good, but a single counter-example proves it is nonsense. Whether or not it is true (about a hot wire fluctuating) has no bearing on whether it is detectable, and whether it is detectable has no bearing on whether effects are undesireable or harmful. Unfortunately, it is also a strawman fallacy to argue that PWM is harmless if it has no visible/invisible effects.

The PWM used by the LightSaver tail switch (for incan E) can under certain conditions cause me to get headaches and migraines, and I have finally discovered how to visually detect it. Also, LED lights with PWM rates in 17kHz range have caused me to get headaches. These facts you've posted about PWM are no longer facts as they are false, respectfully, sir.

 

[Timothybil]

Yes, there is a potentiometer in a household dimmer switch. But it does not have a direct effect on the light. It is used to control the amount of time that elapses after the beginning of the voltage cycle before the semiconductor switch turns on and applies voltage to the light. At one end of the potentiometer's range the semiconductor turns on almost instantly in the cycle, and essentially all of the input voltage is applied to the output. As the potentiometer is turn to dim the light, it causes the semiconductor to turn on later in the cycle, which effectively dims the light because current is flowing for a shorter period of time in each cycle, therefore not allowing the filament to heat up for as long and reducing the total output. Due to the way that A/C works, the output voltage does not start to fall until very late in the cycle. That is why the tint doesn't change very much until the light is down to less than about 30-40%. Just like in an undimmed light, the voltage to the bulb is going to zero 120 times a second, but the latency of the filament makes this much less noticeable then it would be if the light were an LED, with its instant on/instant off.

Now, if this has your brain going zzzt! zzzt!, :shakehead just ignore this and go to the next post.

 

[ssanasisredna]

Yes, there is a potentiometer in a household dimmer switch. But it does not have a direct effect on the light. It is used to control the amount of time that elapses after the beginning of the voltage cycle before the semiconductor switch turns on and applies voltage to the light. At one end of the potentiometer's range the semiconductor turns on almost instantly in the cycle, and essentially all of the input voltage is applied to the output. As the potentiometer is turn to dim the light, it causes the semiconductor to turn on later in the cycle, which effectively dims the light because current is flowing for a shorter period of time in each cycle, therefore not allowing the filament to heat up for as long and reducing the total output. Due to the way that A/C works, the output voltage does not start to fall until very late in the cycle. That is why the tint doesn't change very much until the light is down to less than about 30-40%. Just like in an undimmed light, the voltage to the bulb is going to zero 120 times a second, but the latency of the filament makes this much less noticeable then it would be if the light were an LED, with its instant on/instant off.

Now, if this has your brain going zzzt! zzzt!, :shakehead just ignore this and go to the next post.

... And there may not be a potentiometer. There may be a digital rotary dial, a capacitive strip, push buttons or a micro hooked up an RF link ... And the turn on or turn off may be delayed.

The point is the pot does not directly control voltage which I think was clear in my post.

The instant the voltage drops the CCT starts to change, not at 30-40%. It's always on the black body so one could argue there is no tint. Now you were not clear 30-40% what? Voltage? Total conducted phase angle? Losing the lowest voltage part of the AC waveform has the least effect this is true, but need to be clear about what you are communicating. The effective measure for and incandescent is RMS voltage. At 75% of the rated RMS the CCT of a 2700k incandescent has dropped about 320K ... Quite noticeable.

The flicker is similar to an undimmed bulb but with some higher harmonics that are mostly filtered out.

 

[ssanasisredna]

Apologies for my dissenting opinion, but concerning incan filaments and PWM, this often repeated theory looks good and sounds good, but a single counter-example proves it is nonsense. Whether or not it is true (about a hot wire fluctuating) has no bearing on whether it is detectable, and whether it is detectable has no bearing on whether effects are undesireable or harmful. Unfortunately, it is also a strawman fallacy to argue that PWM is harmless if it has no visible/invisible effects.

The PWM used by the LightSaver tail switch (for incan E) can under certain conditions cause me to get headaches and migraines, and I have finally discovered how to visually detect it. Also, LED lights with PWM rates in 17kHz range have caused me to get headaches. These facts you've posted about PWM are no longer facts as they are false, respectfully, sir.

If you think a 17khz pwm is giving you headaches than you are mistaken. The chemical processes/ neural receptors just don't respond at all at those rates. Nothing is getting through but the equivalent DC signal.

Far more likely with the flashlight is simple eye strain from either inability to focus and/or chromatic effects.

The only way 17khz PWM could impact you is if there is something in your environment that is modulating that 17Khz down to a much lower frequency.

I know you have convinced yourself this is the cause of your migraines but the reality is it is far far more likely to be something else and I suggest seeing an opthalmologist and/or doctor to determine if there is an underlying issue.

You do realize that Incandescent bulbs in the home are for all intents and purposes PWMed at 100 or 120hz right? Flashlights PWM even faster. With an incandescent that means almost no change in output level as the response time of the filament is slow.

With LEDS as noted they respond instantly.

 

[chillinn]

Apparently you have convinced yourself that PWM has no bad health effects. Unfortunate for you that you believe false things. PWM is unnecessary. It is an engineering shortcut indicative of half-assing. I don't understand why individuals insist on defending it. The virtues of PWM are small. It is not worth defending. It is crap. Constant current and voltage circuits are superior in nearly every application. If PWM disappeared from the earth, no one would cry about it. Tint shift at low levels solved by PWM does not outweigh the problems PWM causes for countless individuals, namely, fatigue, and intolerable, crippling pain. The heartless people that PWM doesn't bother seem to want to campaign about how great PWM is and deny that it is harmful to anyone, and they do this, irrationally, in the face of incontrovertible evidence to the contrary. This is absurd.

If you love PWM, that's great. But as for me, nowadays, I only invest in quality hosts and drivers, and I leave the inferior designs for the ignorant masses.

 

[vicv]

As stated already all AC light are are basically pwm because of the 60hz AC frequency. That being said it's also been said over and over it doesn't matter whether you like it or not I'm afraid to say. It's the only way to dim an incandescent/halogen/xenon bulb. Cc circuits limit the voltage to the led. That will not work for a filiment bulb. Period. End of story. What you want isn't beyond the scope of current technology. It's beyond the scope of physics

 

[chillinn]

As stated already all AC light are are basically pwm because of the 60hz AC frequency. That being said it's also been said over and over it doesn't matter whether you like it or not I'm afraid to say. It's the only way to dim an incandescent/halogen/xenon bulb. Cc circuits limit the voltage to the led. That will not work for a filiment bulb. Period. End of story. What you want isn't beyond the scope of current technology. It's beyond the scope of physics

AC lighting in fact oscillates at 120Hz, twice 60Hz. It is similar in theory to PWM, but not in practice. The dimming of the filiment in fixed lighting due to AC power is miniscule, as shown by slowed video (I've seen on youtube). If AC fixed lighting was the same as PWM, then it would have the same effects. It is not the same in effect, thus it is really not at all the same.

What you have explained before that you now left out is concerning the tint shift yellowing of the lamp at lower voltages. This is unacceptable to you and some others, but it still is a valid way to power a lamp, and this is proven by your own practice of on occassion using your primary cells until empty (why would you ever do that if you could not use the yellow dimmer light of the lamp?).

Everything you posted is true, but if and only if you preface it by "in order to run a lamp at the specified designed voltage in order to get the proper efficient output and color temperature, then..."

You must see your statements as false, otherwise. My dimmer switch proves it, unless it is magic.

 

[vicv]

Ok the install a pot in series with the bulb. I wouldn't consider it state of the art driver but will do everything you want
And no it's 60hz. It flips from +~170v to -~170v 120 times a second for an rms voltage of 120v but that's still 60hz

 

[chillinn]

fyi

Lamps operating on AC electric systems (alternating current) produce light flickering at a frequency of 120 Hertz (Hz, cycles per second), twice the power line frequency of 60 Hz (50 Hz in many countries outside North America). Essentially, the power is turning on and off 120 times a second (actually the voltage varies from +120 volts to -120 volts, 60 times or cycles a second and is at zero volts twice in one cycle).

Thanks, vicv. I think something similar has been done for LED, but smooth dimming isn't really what I'm after, just modes... and the reason is the pathetic capacity of secondaries. A 50% power mode to double capacity, and a 25% power mode to quadruple it, and implemented in a way that the light is reasonably constant output as it dims from the depleated cell voltage, and with the understanding that the lamp is not going to be ideally lit at those lower voltage levels, and I'd be very satisfied. Add softstart and regulation... and fit this all in a common E tailcap, and I'd need to find homes for all the kittens suddenly appearing on my seat.

 

[vicv]

That does all sound great. Only possible with pwm. Also realise that even cc LEDs are done with pwm. Any voltage regulator is called a switching DC-DC convertor. The switching part means turning off and on. That's pwm. It's just filtered before it gets to the emitter

 

[chillinn]

That does all sound great. Only possible with pwm. Also realise that even cc LEDs are done with pwm. Any voltage regulator is called a switching DC-DC convertor. The switching part means turning off and on. That's pwm. It's just filtered before it gets to the emitter

Interesting, but the only PWM of concern is the kind that messes with the light output level.

Also seems like this insurmountable request should not be so. Consider that a single mode incandescent flashlight will output x brightness when the cell voltage is 3.3V, and a lower y brightness when the cell voltage is 3.0V, and still yet a lower z brightness when the cell is 2.7V. If only there were some existing and well-understood engineering or science where we could introduce some kind of voltage resistence to effectively limit or buck the voltage of a fully charged cell without using PWM and without incurring too much disadvantage of losing the capacity of that extra voltage, and implement it in such a way that it was switchable between these modest couple extra lower modes. But of course this is the stuff of science fiction.

 

[ssanasisredna]

Apparently you have convinced yourself that PWM has no bad health effects. Unfortunate for you that you believe false things. PWM is unnecessary. It is an engineering shortcut indicative of half-assing. I don't understand why individuals insist on defending it. The virtues of PWM are small. It is not worth defending. It is crap. Constant current and voltage circuits are superior in nearly every application. If PWM disappeared from the earth, no one would cry about it. Tint shift at low levels solved by PWM does not outweigh the problems PWM causes for countless individuals, namely, fatigue, and intolerable, crippling pain. The heartless people that PWM doesn't bother seem to want to campaign about how great PWM is and deny that it is harmful to anyone, and they do this, irrationally, in the face of incontrovertible evidence to the contrary. This is absurd.

If you love PWM, that's great. But as for me, nowadays, I only invest in quality hosts and drivers, and I leave the inferior designs for the ignorant masses.

If you have read what I wrote, I know for a fact that PWM causes headaches in many people at low frequencies, generally sub 200Hz. There are visual effects with 100% modulated PWM up to 500Khz, and you can detect with perfect conditions up to 1KHz (i.e. cause sub-frequency modulation). At 17KHz, there is not. That is not me convincing myself, that is the body of evidence of people who have studied this, PLUS a fairly good knowledge of how the eye detects light and processes optical signals.

There is nothing "inferior" about PWM, in fact a truly superior driver will mix both constant current and PWM as it maximizes the efficiency of the LED.

Quite a few LED drivers for commercial lighting use PWM as well when dimmed. It is relatively common and is going to become more common as more fixtures incorporate white point tuning, color changing, etc. Planes with color changing LED lighting are also typically PWM. For many requirements it is a superior technique.

Incandescent off the AC mains IS effectively PWM, but without full modulation depth due to thermal mass of the filament. You can try to call it something else, but the effect is PWM, hence why there is 120Hz ripple in an incandescent lights output. When you hook up a dimmer, it really does become PWM, but again the filament has "heat storage". PWM of an incandescent bulb will behave EXACTLY the same. There is no difference. None, nada, nothing.

High frequency PWM of LED behaves the same too, but in this case, you have chemical storage (eye, etc.) that smooths out fast changes.

Vicv, the line frequency is 60Hz, but from a lighting standpoint, it's 120Hz.

 

[Kestrel]

I don't really have anything to add here, but if anybody here hasn't read up on the ph-d M6 regulated battery pack project for the M6, it really is fascinating reading. There are ~3 threads for about ~100 pages total; probably the finest work ever done with flashlight incan technology. Highly recommended reading.

 

[chillinn]

Thanks, Kestrel

ssanasisredna, the problem is that you believe these things, concerning PWM rates above 17kHz, even though I am telling you in fact these PWM rates (17.5kHz specifically) caused me to get headaches and migraines. The effect is not instantaneous, but cummulative. There is nothing else in the environment modulating anything, and nothing else to mitigate the plain fact that this is so, and yet, you resist the notion based upon idk what you're talking about, these unreferenced "studies." "Not possible," you irrationally and quite frankly, incorrectly and wrongly believe these falsehoods, even though I am telling you honestly, first person experience here, not something I heard or read about, supposedly, but in fact me the man himself and a source of grievance concerning this menace of a technology telling you in fact PWM rates are indeed actually a real health issue for me and likely many others. "No," you're going to eventually reply. What's the smiley for this?

To avoid the PWM battle and get back on track...

what I have gleaned so far is that the issue is unlike the way the problem is solved with LED, using a constant current, because lamps are voltage controlled. Further, lamps are designed to be efficient and have the ideal color temperature at a certain voltage, and lower voltages will cause efficiency to drop (please confirm), and color temp to dip warmer and yellower. PWM with incan attempts to solve this, but in my experience, and documented elsewhere on CPF by others, there is still tint shift with incan PWM implementation.

Ignoring the efficiency and color temperature issues, if anyone has the patience or inclination, I would not mind a better understanding of how the current is controlled (or not) in a simple incan as the cell voltage drops. What exactly decides what the current is in an incan without a driver? I realize current and voltage are going to be related, but I don't have my head around it.

Lastly, if the efficiency and color temp issues could be ignored or tolerated, by what method could voltage be limited in a couple different stages without pulsing the filiment with PWM or something like PWM?

 

[fyrstormer]

The basic answer is: Electronics that can regulate current flow at the amperage incandescent bulbs use would be too large for flashlights. It is much easier to pulse the power supply as a form of regulation, and an incandescent bulb won't show the pulsing because the filament takes time to cool down and stop glowing.

EDIT: There IS, however, a small amount of noise generated by the filament vibrating from the PWM effect, and it's possible you're hearing that noise and it's causing you to get headaches. But there is no way you are *seeing* the pulses, not with an incandescent bulb. It is physically impossible for you to see it because your eyes couldn't respond fast enough, even if the bulb itself were flickering at 17.5kHz.

 

[chillinn]

The basic answer is: Electronics that can regulate current flow at the amperage incandescent bulbs use would be too large for flashlights. It is much easier to pulse the power supply as a form of regulation, and an incandescent bulb won't show the pulsing because the filament takes time to cool down and stop glowing.

EDIT: There IS, however, a small amount of noise generated by the filament vibrating from the PWM effect, and it's possible you're hearing that noise and it's causing you to get headaches. But there is no way you are *seeing* the pulses, not with an incandescent bulb. It is physically impossible for you to see it because your eyes couldn't respond fast enough, even if the bulb itself were flickering at 17.5kHz.

Thanks fyrstormer, first part feels like another death blow, but an example would still help.

Second part there... concerning this business about seeing PWM. Whether it is seen is irrelevant. I cannot see 17.5kHz PWM. Using the Lightsaver tailcap (for incan), I generally cannot see the PWM in the lower modes. This is kind of a red herring bit of evidence trying to support the idea that PWM isn't bad. You can't see CO2, so it's not killing you. You can't see that cavity, so it must not be causing you any pain.

But I've read enough of your posts that I welcome anything you have to share. The bit about the amperage levels in incan and modern analog electronics... new to me... i mean, had some idea the amps were going to be greater in incan, but no idea that the hardware wasn't there for minature high amp apps.

 

[archimedes]

Have you tried QTC ?

 

[chillinn]

Have you tried QTC ?

I wonder if that could work in a momentary switch/twisty like the z52, to the effect of the momentary action and twisty action allowing the user to adjust the light level by pressure. I wonder if it could be that simple, to just stick some composite in a switch, around the inside lip where it contacts... I wonder if I could just contact Peak and have it made... :thinking: