So you and Dor's mom indeed represent 2 opposite ends of the "spectrum" of people's reaction to light sources CCT, and possibly light levels



My own light preferences :

To me proper indoor lighting is mostly the spectrum of Fluorescents. I do well with most FL from 640 to 765 and from 827 to 865. Some of the 827 is a bit borderline in terms of color preference (too pink), but in terms of seeing is ok. (827 varies a lot between manufacturers and lamp types, i noticed that most PL-type lamps 827 looks much better than what's typical for E27 CFLs)

For general area lighting my light levels are low. 11W/840 PL-S (and possibly with an opaque lamp shade that may reduce the level a lot) is sufficient to light a 3x4m room, and a few and far between 36w/765 T8's light up my workshop

On the electronics bench i do use more light. Currently in my workshop desk there is a 2x80W/840 T5 above the desk, which is over the top in light levels, but does indeed help looking at small SMD stuff

Incandescent/Halogen while i can see well, i would like a bit higher CCT. (Here 12V Halogens are indeed a little better)

LED anything >2700K does not look right - it appears to be deceiving in color rendering, and >4000K also makes for noticable extra load on the eyes. Not usable in any long term general or task lighting. No such problem with any FL, up to and including 765 and 865

LED 2000K (got a couple of those "vintage" filament lamps with gold-colored glass) does not look too bad, in particular because it does not appear to be trying to look like a white light source. It is "explicitly" a color light, its blue light content is as low as can be for a "blue and phosphor" LED



However, one setup with LED i installed very recently - a dark outdoor place around the workshop, where i installed lighting on a staircase timer (controlled by buttons from 2 ends from which you can walk there). Lamp is a 20W 1800lm 2900K snow cone in a white plastic posttop moon balloon lantern. It switches on to immediate full brightness, it won't melt a hole in the lantern if let to run for too long, and its life probably won't be cut short by the frequent starting

It is borderline in terms of preserving night vision (if i look under its light and then into the dark wilderness around), though being just 2000lm, in a 300mm moon baloon, on a 4m pole, its effect is minimized

I might convert it to Incandescent if i choose at some point to change to a metal/glass lantern, eliminating the risk of melting, but for now let's evaluate the setup as it is



I think the real definition of glare is by the perception of glare, which may involve quite some quirks of how our vision works. I think it comes down to 2 things :

 - Relation between brightness of the light source seen in the peripheral vision vs. the areas that are intended to be illuminated

 - Relation between brightness of the light source seen in the peripheral vision vs. the background area visible behind the light source

Reflected brighter areas from a wet road surface - I would intuitively not define it as glare, unless it is extreme. Maybe as non-uniformity in the appearance of the road ok, but then i think all the big rush for perfect uniformity is BS anyway, uniformity does not lead to better visibility

I asked a while ago about the specifics of SRS ballasting, and got a little bit of useful info. Since then I have looked at plenty of resources, but I have more questions. Here is a schematic of an SRS fluorescent ballasting circuit:

Here are my questions about it:

---

1) Construction Specifics:
The iron core shown has two isolated windings. I have heard this called a "double choke" before. In my eyes this is implying that both windings are equal. Are both windings the same? If not, what is the approximate turns ratio?

2) Working Principle:
I have tried to get a grasp on how this is supposed to work, but I am really having a problem. Can someone explain?

3) Abbreviation Meaning:
I think I heard somewhere that SRS stands for "Semi-Resonant Start", but I don't know for sure because everyone always just calls is "SRS". What does it mean?

---

Thanks!

Deja Vu?

https://www.lighting-gallery.net/index.php?topic=17737.0

did you not read the awesome technical pocket booklet I linked in that thread? that explains the fundamental theory/working of Semi-resonant-start quite well


(tho does not go into turns ratios or things like that)

I asked a while ago about the specifics of SRS ballasting, and got a little bit of useful info. Since then I have looked at plenty of resources, but I have more questions. Here is a schematic of an SRS fluorescent ballasting circuit:

Here are my questions about it:

---

1) Construction Specifics:
The iron core shown has two isolated windings. I have heard this called a "double choke" before. In my eyes this is implying that both windings are equal. Are both windings the same? If not, what is the approximate turns ratio?

2) Working Principle:
I have tried to get a grasp on how this is supposed to work, but I am really having a problem. Can someone explain?

3) Abbreviation Meaning:
I think I heard somewhere that SRS stands for "Semi-Resonant Start", but I don't know for sure because everyone always just calls is "SRS". What does it mean?

---

Thanks!

Alright, I just was able to go home and measure the voltage and current with my RMS meter.

On a 100W MH ballast
- 128V
- .99A

So it is pretty overdriven on a 100W MH ballast.

Does anyone have a 100W MV lamp and a 70W MH ballast that they are willing to measure and see? The MH ballast can be pulse-start, as long as you remove the ignitor.

Glare is defined by the surface brightness of the light source.

Higher color temperatures are associated with higher visual acuity, so your mother is right in noting she can see better with that kind of light. Just like with your hearing, your eyesight also can slowly degrade as you get older. I am 35 and still can do fine without glasses, but my parents and grandparents all needed some form of glasses at some point in their life.

I have noticed it myself. I used to light my old bedroom which doubled as electronics workshop with a 40w or 60w bare incandescent in the ceiling. When i switched to a long life incandescent with roughly the same light output, i felt like i couldn't see properly anymore. Those long life things run at a lower temperature so you get a lower CCT. With a 60w longlife i could see less than with a 40w normal one.

For me personally, any higher than 3000k doesn't feel like it has any benefits as workpiece lighting. In the lab at work we have color 830 fluorescents (for now, they'll be ledified in about a year's time...) and 6500k feels like i can't see colors properly anymore unless the light is particularly bright and of a higher CRI than your bog standard LED has to offer.


With regards to glare - how do you define it here? Reflected light from a wet road, or the visibility of the light source in your periferal vision?

The judging of lamp brightness by its glare is not result of damage, but simply of the appearance of high glare LED light sources, everywhere where the previous sources were not as glaring :

 - Flat panels with flat light distribution replacing highly directional reflector modular luminaires (4x18W)

 - Floodlights lacking any optics whatsoever replacing way bigger in size HID floodlights which did have optics

This had been going on, and actively abused for sales and promotion, since the earliest days of high power LED lighting, so way before anyone had the time to get vision damage

With additional vision damage the demand for bright light (which tends to correlate with being 6500K, probably to compensate for the degraded S cone cells) will remain the same or increase

Your mom is on one end of the scale, where for many it is the opposite effect. Of those who want bright light like your mom, i wonder how much of it is attributed to actual vision damage (whether from LEDs or just from age and other health factors), vs. how much when actually seeing the same "picture" as me (for example) but claiming that it is not bright enough, in the same cases where i would consider the light level adequate

The fact that lots of people judging the intensity of LED lamps by the glare of it, proves my thoughts about degenerate of the vision of people.
Also: My brother and my father and my mother all preferring >6000K, because they saying it is brighter than 2700K, and my mother because she don't see well with <4000K light.

Color temperature is very strongly correlated to cultural background here. In row homes where families are mostly from western european descent, 2700k.
In apartment blocks, where many of the turkush, morroccan and middle eastern people live, you'll find 4000 and 6500 more often because of the apparent correlation between living near the equator/in a very warm country, and wanting a cooler shade of light.

Always been like that only in the pre-led days, their only choice was 4000k circular (kinda rare) or linear fluorescents in the living room. CFLs we didn't have in 4000k, unless you went for PL but at hardware stores all PL fixtures were meant for outside use. So only the die-hard fans of cold white light would have a brightly shining fluorescent right in their living room.

The length of arc in air which this PZT ignitor can produce can give you an estimate of the order of magnitude of its output voltage

In uniform field, air requires 3kV/mm to break down with high probability, with some behavior properties :

 - ionization is always a statistical phenomena, dependent also on factors like photoelectric effect and radiation

 - The presence of a nearby surface of a different material, even if it is in itself dielectric, may sometimes facilitate the arc striking in a path from one electrode towards the surface, in a straight line on the surface layer, and to the other electrode

 - Some surfaces of solid materials may have additional insulation breakdown mechanisms such as tracking, which will happen at way lower field strengths. However, the initial starting of tracking is a relatively slow phenomena and unlikely to happen with the fast pulse of a PZT. Air by itself does not have such mechanisms, only the basic breakdown as result of applied field

 - If you are looking instead for a distance which is safe to NOT break down, that would be no more than few 100's V/mm, and that's without any surface related mechanisms. The AC voltage ratings vs. contact opening distance of small low current relays may give you an estimate here

In non uniform field, the electric field will be concentrated near sharp edges. This means that even if your real voltage and distance between electrodes would calculate as lower field strength, there still will be a region of field way above the 3kV/mm. Once a small region is ionized, it is easy for the arc to spread from there to anywhere else as needed to complete the circuit, even where initially the field is weak

The lamp glass wall have up to 10x the permittivity of air, alumina (HPS arctubes) also 10x, and quartz 4x. (abridged explanation : imagine the 1mm glass wall behaving as a 10mm air gap etc)

The atmosphere in the lamp outer is generally vacuum or nitrogen, which have permittivity same as air

With this said, try to imagine if the arc would reach the lamp electrodes if you would zap it as you do, from the same position, if there would be no lamp or arctube or outer envelope there, but just the PZT and bare lamp electrodes at the respective distances (with the extra air distances that represent the arctube and lamp walls)

If it does, odds are it can strike the arc. If it does not, it may still strike it, because there may be additional conditions which reduce the extra "push" the lamp needs in the 1st place