Difference between revisions of "Lightbulb notes"

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==Technical side==
 
==Technical side==
  
===Incandescent lamps===
+
===Incandescent and halogen lamps===
 
<!--
 
<!--
  
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'''Halogen lamps''' are a variant on incandescent,
 
'''Halogen lamps''' are a variant on incandescent,
 
the name referring to the [https://en.wikipedia.org/wiki/Halogen_lamp#Halogen_cycle halogen cycle] redepositing some of the freed filament metal back onto the filament.
 
the name referring to the [https://en.wikipedia.org/wiki/Halogen_lamp#Halogen_cycle halogen cycle] redepositing some of the freed filament metal back onto the filament.
This requires a halogen gas, and for the bulb to burn about twice as hot as is practical for most incandescent,
+
This requires a halogen gas, and for the bulb to burn about twice as hot as is practical for most incandescent, which is part of why these are usually higher-power bulbs and associated with bright lights (and also why they may use quartz glass, which deals with higher temperatures).
which is part of why these are usually higher-power bulbs and associated with bright lights.
+
  
 
Halogen can be driven from AC (e.g. just a transformer) or DC.
 
Halogen can be driven from AC (e.g. just a transformer) or DC.
Line 41: Line 40:
  
 
While in cold climates this may help heat your house electrically, in general and in warm climates it's a waste product that is avoidable.
 
While in cold climates this may help heat your house electrically, in general and in warm climates it's a waste product that is avoidable.
 +
 +
  
  
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====Neon glow lamps====
 
====Neon glow lamps====
 
<!--
 
<!--
'''Neon glow lamps''' [https://en.wikipedia.org/wiki/Neon_lamp] are a different design gas discharge lamp from neon tube lighting, much smaller and historically mostly indicator lights.  
+
'''Neon glow lamps''' [https://en.wikipedia.org/wiki/Neon_lamp] are a different design gas discharge lamp from neon tube lighting, much smaller.  
  
Most designs will glow above around 90 volts.
+
Mostly used as indicator lights.  
  
As they age, they start needing a higher voltage - which in most uses means they start flickering and turn off.
+
Most designs will glow above approximately 90 volts.
 +
 
 +
As they age, they start needing a higher voltage - which in most uses means they start flickering, and later turn off.
  
  
 
The most typical variant is orange.
 
The most typical variant is orange.
 
Other colors can be had with different gas mixtures, and more easily by using phosphors.
 
Other colors can be had with different gas mixtures, and more easily by using phosphors.
 +
  
 
Once more common, now probably most commonly seen as power strip switch indicators {{verify}}.
 
Once more common, now probably most commonly seen as power strip switch indicators {{verify}}.
  
: the breakdown characteristics means they can be used for voltage regulation, and as overvoltage protection.
+
Other uses
: voltage indicators -
+
: the breakdown characteristics means they can be used for voltage regulation
:: if you can see both parts, you can tell the difference between AC and DC, and polatity of DC
+
 
 +
: ...and as overvoltage protection.
 +
 
 +
: voltage indicators
 +
:: if you can see both parts of the bulb, you can also tell the difference between AC and DC, and polarity of DC
 +
 
 
: oscillators
 
: oscillators
 +
 
: simple photosensors.
 
: simple photosensors.
  
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===VFDs===
 
===VFDs===
<!--
+
{{stub}}
When you see displays with large-ish segments having fairly high contrast, and looking up close reveals a fine grid pattern, these are '''Vacuum Fluorescent Display'''s (VFD) [https://en.wikipedia.org/wiki/Vacuum_fluorescent_display].
+
  
They have a phosphor-coated anode, a cathode to generate electrons, and a mesh grid inbetween to switch themm and are in a low-pressure tube.  
+
[[Image:VFD.jpg|thumb|right|350px|VFD closeup]]
 +
<!--When you see displays that you suspect ''might'' be little text-shaped masks backlit with LED, but maybe a bit old or different, look closer.
  
So they resemble a [[vaccum tube]] triodes in how it is operated and a CRT in why they light up (see also [https://en.wikipedia.org/wiki/Cathodoluminescence cathodoluminescence]).
+
If looking close reveals a fine non-square grid pattern, they are probably '''Vacuum Fluorescent Display'''s (VFD) [https://en.wikipedia.org/wiki/Vacuum_fluorescent_display].
  
They are ~30V devices (order of magnitude), so by modern TTL standards,
 
they need somewhat unusual voltages, and a dedicated controller.
 
  
These often have a light blueish-green color (sometimes darker, using colored plastic in front), where the color comes from the choice of phosphor.
+
They have a phosphor-coated anode, a cathode to generate electrons, and a mesh grid inbetween to switch them, and are in a low-pressure enclosure (typically glass, often rectangular''ish'' because of what they contain) because air would make them stop working.
Red, orange, and yellow are also seen.
+
VFDs are seen on microwave clocks (there sometimes just 7-segment), audio gear (where little symbols light up as a whole), and there are also dot matrix variants (e.g. in older cash registers) which works out to be fairly cheap to do since the segments are typically multiplexed anyway.
+
  
 +
So yes, they resemble a [[vacuum tube]] triodes in how they are driven, and a CRT in why they light up (see also [https://en.wikipedia.org/wiki/Cathodoluminescence cathodoluminescence]).
  
In the seventies and eighties VFDs were a sensible and flexible choice - bright enough for lit environments and dimmable to be subtle in the dark; readable from all angles (unlike backlit LCD), fine detail and high contrast.  
+
They are ~30V devices (order of magnitude), so need their own voltage supply, and also a dedicated controller.
 +
 
 +
 
 +
They frequentlyhave a light blueish-green color (sometimes darker, using colored plastic in front), related to the choice of phosphor. Red, orange, and yellow are also common enough.
 +
 
 +
 
 +
Places you may see VFDs include microwave clocks (though those are now frequently 7-segment LEDs), audio gear (where little symbols light up as a whole).
 +
 
 +
But yes, there are also dot matrix variants (e.g. in older cash registers) which works out to be fairly cheap to do since the segments are typically multiplexed anyway (which is less blinky than LED because phosphors).
 +
 
 +
 
 +
In the seventies and eighties VFDs were a sensible and flexible choice - bright enough to be clear in lit environments and readable from all angles (unlike backlit LCD), dimmable to be subtle in the dark, fine detail and high contrast.  
  
 
7-segment is now frequently LED, being cheaper and more robust.
 
7-segment is now frequently LED, being cheaper and more robust.
 
These days there's also OLED doing fine detail, high contrast, more colors, smaller and less fragile, but VFD is still cheaper than OLED.
 
These days there's also OLED doing fine detail, high contrast, more colors, smaller and less fragile, but VFD is still cheaper than OLED.
 +
 +
<br style="clear:both">
 
-->
 
-->
 
  
 
===LED===
 
===LED===
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A lot of type of lightbulbs flicker,
 
A lot of type of lightbulbs flicker,
  
incandescent does, only a little because the glowing changes slowly
+
Incandescent does, only a little because being so hot, the temperature variation of the filament only changes so much (yet still perceptibly, because of small thermal mass).
 +
 
  
 
'''fluorescent tubes''' vary
 
'''fluorescent tubes''' vary
: choke ballasts present mains at mains frequency, and while the tube phosphors aren't instant, they are still fairly fast and flicker somewhat
+
: classic choke ballasts present mains at mains frequency, and while the tube phosphors aren't instant, they are still fairly fast and flicker somewhat
: modern ballasts can be seen as switch-mode supplies, at >20kHz, so the flickering in the tube is barely there
+
: modern ballasts ore more like switch-mode supplies, often at >20kHz, so the flickering in the tube is barely there
 
: e.g. Offices often specifically adopt modern ballasts, because some people are sensitive to to the older style.
 
: e.g. Offices often specifically adopt modern ballasts, because some people are sensitive to to the older style.
  
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* a phosphor layer that will glow when AC is closeby (due to excited electrons)
 
* a phosphor layer that will glow when AC is closeby (due to excited electrons)
 
* a protective layer
 
* a protective layer
* often also a colored layer (also further protection)
+
* often also a colored layer (also acts as further protection)
  
  
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It's quite energy efficient, and cold, though not very bright.
 
It's quite energy efficient, and cold, though not very bright.
  
EL wire wears due to use,  
+
EL wire wears from use,  
 
and from driving at higher voltages,
 
and from driving at higher voltages,
the colored sheath will probably fade with a lot of sunlight exposure,
+
the colored sheath will probably fade with a lot of sunlight exposure.
  
  
 
Safety:  
 
Safety:  
* Due to the low current capacity of almost any drive circuit, it's extremely unlikely to hurt you even if you do get through both sheathes.
+
* Due to the low current capacity of almost any drive circuit, it's unlikely to hurt you even if you do get through both sheathes.
: heat-shrink any connections
+
: heat-shrinking any connections is still recommended, though
  
 
* Designs may draw more current from batteries than they are comfortable with, causing them to heat up.
 
* Designs may draw more current from batteries than they are comfortable with, causing them to heat up.
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===Edison screw===
 
===Edison screw===
 
+
[[File:Edison screw.jpeg|thumb|right|370px|Edison screw (E27, E14)]]
 
Typical for lightbulb/pear shapes.
 
Typical for lightbulb/pear shapes.
 
The number is the outer diameter of the metal screw part in mm.
 
The number is the outer diameter of the metal screw part in mm.
Line 619: Line 639:
  
  
<!--
 
* There's a generally-less common, even-smaller variant E11 (Europe), E12 (US)
 
  
* There's also 'Mogul': E40 (Europe), E39 (US), e.g. used in older stage lighting
+
There are a handful of other diameters in use, e.g.
 +
: E10 (miniature) in older flashlights, indicator lights, bike lights
 +
: uncommon now in all those uses, because e.g. LED is more efficient than incandescent
  
And perhaps
+
: E39/E40 (giant/'mogul') in industrial / older stage lighting
* E10 - older flashlights, indicator lights, bike lights
+
: getting less common, because e.g. LED is more efficient than incandescent
+
-->
+
  
There are a handful of other diameters in use (christmast lights, industrial)
 
 
<!--
 
<!--
 +
* There's a generally-less common, even-smaller variant E11 (Europe), E12 (US)
 +
 +
The US also has E11, E26, and E39 ('mogul'), which are typically interchangeable with E10, E27 and E40 respectively
 +
 
E5 5mm Lilliput Edison Screw LES
 
E5 5mm Lilliput Edison Screw LES
 
E10 10mm Miniature Edison Screw MES
 
E10 10mm Miniature Edison Screw MES
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E40 40mm Giant Edison Screw GES
 
E40 40mm Giant Edison Screw GES
  
The US also has E11, E26, and E39 ('mogul'), which are typically interchangeable with E10, E27 and E40 respectively
 
 
 
https://en.wikipedia.org/wiki/Edison_screw
 
 
-->
 
-->
  
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{{stub}}
 
{{stub}}
  
Many of these are IEC 7004.
+
Many bi-post are IEC 7004 {{verify}}
 +
 
 +
You may like overviews from image searches for terms like {{imagesearch|light bulb socket types diagram}}
 +
 
  
 
The number specifies the pin distance.
 
The number specifies the pin distance.
Line 659: Line 678:
  
  
[[File:GU10 GX53.png|220px|thumb|right|GU10 (230V MR16), GX5.3 (12V MR16 bulb)]]
+
[[File:GU10 GX53.png|200px|thumb|right|GU10 (230V MR16), GX5.3 (12V MR16 bulb)]]
 +
[[File:G9.jpg|170px|thumb|right|G9 with its loops]]
 
'''Variants with smaller distances''' are typically small spots (classically halogen), for example:
 
'''Variants with smaller distances''' are typically small spots (classically halogen), for example:
 
* {{imagesearch|GU10}} - pins, 10mm distance, widened bayonet-style end (seems to be one of only a few G variants that has that bayonet)
 
* {{imagesearch|GU10}} - pins, 10mm distance, widened bayonet-style end (seems to be one of only a few G variants that has that bayonet)
 
* {{imagesearch|GX5.3}} - pins, 5.33mm distance
 
* {{imagesearch|GX5.3}} - pins, 5.33mm distance
 
* {{imagesearch|G4+bulb|G4}} - pins (4mm distance, thinner)
 
* {{imagesearch|G4+bulb|G4}} - pins (4mm distance, thinner)
These may be easy to find in supermarkets and such.  
+
* {{imagesearch|G9+bulb|G9}} - flat loops, 9mm between the centers of the loops
 +
These may be easy to find in supermarkets and such - though the exact set varies a little with where you live.
  
  
  
'''Larger variants''' like
 
* {{imagesearch|G23 socket|G23}} and {{imagesearch|G24 socket|G24}} are used in office lighting.
 
  
* {{imagesearch|G53 socket bulb|G53}} is used e.g. in larger [[PAR]] spots
 
 
 
See also overviews from image searches for terms like {{imagesearch|light bulb socket types diagram}}
 
  
  
  
 +
'''Larger variants''' like
 +
* {{imagesearch|G23 socket|G23}} and {{imagesearch|G24 socket|G24}} are used in office lighting.
  
 +
* {{imagesearch|G53 socket bulb|G53}} is used e.g. in larger [[PAR]] spots
  
  
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A few further details/associations are specified by the letters, e.g. G, GU, GX, GY, GZ.
 
A few further details/associations are specified by the letters, e.g. G, GU, GX, GY, GZ.
  
For example, GZ bulbs use dichroic glass, which dissipate most of the heat so lets out most of the heat at the back.
+
For example, GZ bulbs use [https://en.wikipedia.org/wiki/Dichroic_glass dichroic glass], which dissipate most of the heat so lets out most of the heat at the back.
 +
 
 +
Power and beam angle may wel be specified [http://en.wikipedia.org/wiki/Multifaceted_reflector#ANSI_designations] though have some inconsistencies in specification.
  
  
Once you get to products, there are more variations, and more is specified, e.g.
 
Power and beam angle can be specified [http://en.wikipedia.org/wiki/Multifaceted_reflector#ANSI_designations].
 
  
While endless combinations between socket, bulb, and voltage ''could'' exist, there is a lot of consistency in what is actually produced,
+
While endless combinations between socket, bulb, and voltage ''could'' exist, there is a lot of consistency in what is actually produced, so in practice most most further details are (only) implied from most specific references being unique{{verify}}.
so in practice most most further details are (only) implied from most specific references being unique{{verify}}.
+
  
 
For example:
 
For example:
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{{stub}}
 
{{stub}}
  
Yes, but only really for halogen bulbs, and then not all.
+
Yes, but only really for halogen bulbs, and then only a subset of them.
  
  
 +
In the realm of lightbulbs, halogen bulbs are one of a few that specifically uses quartz glass, because quartz can deal with higher pressure and temperatures.
  
'''Devitrification'''
+
Note that some quartz designs don't need to, or use an additional regular-glass envelope around the quartz envelope (in part to protect against large temperature differences), in which case the below doesn't apply.
  
The main reason is devitrification.
+
Apparently applies less to a lot of professional high-powered lighting, in that much of that uses hardglass.
  
For context: Vitreous means glass-like, here referring to a random-rather-than-crystalline structure (applies to any material you can get to do both, including water[https://en.wikipedia.org/wiki/Amorphous_ice]).
+
But unless you can reliably tell, it's good habit / rule of thumb to not touch anything that looks halogen.
  
Devitrification means something glassy returns to a more crystalline form.
 
This happens more easily with higher temperatures, and/or when there is a nucleation center for a crystalline structure to start growing.
 
  
Devitrification of clean quartz usually only happens noticeably above 1200 °C (in most typical glasses it's around 1400 °C{{verify}}), but with surface impurities can start happening below 1000 °C.
 
  
Because of crystal properties, it will look cloudier.
+
When using quartz glass, there are two extra things that can happen.
Which in high powered lightbulbs is just not useful.
+
  
 +
One is devitrification, a change of the crystal structure from a more random to a more crystalline form. In glass this happens more easily with higher temperatures, and/or when there is a nucleation center for a crystalline structure to start growing, which happens more easily when there are surface impurities.
  
 +
Because of crystal properties of clear quartz, this will easily make it look cloudier, which is not very useful in a lightbulb.
  
In the realm of lightbulbs, this mostly applies to halogen bulbs, because their direct envelope is likely to be quartz.
+
Devitrification by itself barely affects bulb life, though.
{{comment|(not all halogen bulbs uses quartz, as some don't need to. Some use an additional regular-glass envelope. But unless you can reliably tell, it's good habit / rule of thumb to not touch anything that looks halogen-bulby)}}
+
   
  
 +
The fat and protein from your fingers could create hot spots - which puts a temperature differential and thereby the amount of stress while it heats, probably breaking it sooner, sometimes much.
 +
 +
In theory, a little oil may just burn and sputter off soon enough - it's more that in some cases it could sort of etch itself in.
  
 
<!--
 
<!--
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The issue is that quartz can devitrify much more easily than regular glass - for a large part ''because'' they run hotter (mostly because halogen bulb's halogen cycle only works above ~250 °C) - on the order of 500 °C, while incandescent is usually on the order of 150 °C.  
 
The issue is that quartz can devitrify much more easily than regular glass - for a large part ''because'' they run hotter (mostly because halogen bulb's halogen cycle only works above ~250 °C) - on the order of 500 °C, while incandescent is usually on the order of 150 °C.  
 
 
Apparently applies less to a lot of professional high-powered lighting, in that much of that uses hardglass.
 
 
 
  
  
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https://en.wikipedia.org/wiki/Halogen_lamp#Halogen_cycle
 
https://en.wikipedia.org/wiki/Halogen_lamp#Halogen_cycle
 
-->
 
 
'''Hotspots'''
 
 
<!--
 
Devitrification by itself barely affects bulb life.
 
 
The other reason you hear is that they could create hot spots.
 
 
Say, if your hands were very fatty, though, the presence of oil while it heats up puts a temperature differential while it heats up, which can put enough force on that area of the quartz while it heats, that it ''could'' potentially break.
 
 
This too applies more to halogen, as they burn hotter.
 
 
Yet a little oil, if it doesn't do this quickly soon, will often mean it burn and sputter off soon enough.{{verify}}
 
 
 
(also e.g. why some drinking glasses shouldn't be used for tea, because pouring ~100C water to the side of a ~20C glass can do this).
 
 
  
 
-->
 
-->

Latest revision as of 15:54, 4 May 2021

Lightsource types

Technical side

Incandescent and halogen lamps

Gas discharge lamps (arc discharge, glow discharge)

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)


Carbon arc lamps

Fluorescent lamps

On ballasts

Mercury and sodium vapor lamp

Metal halide lamp

Neon glow lamps

Nixie tubes

Further notes

VFDs

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)
VFD closeup

LED

On flickering

On dimming

EL wire

Product side

Lightbulb sockets

Edison screw

Edison screw (E27, E14)

Typical for lightbulb/pear shapes. The number is the outer diameter of the metal screw part in mm.

There's quite a few of them, but by far most common are:

  • E26/E27 - common large screw variant
Apparently there's a correlation where E26 is for 120V countries and E27 for 230V countries(verify), but they're close enough
  • The more common small variant is usually E14 (Europe) and E17 (US)


There are a handful of other diameters in use, e.g.

E10 (miniature) in older flashlights, indicator lights, bike lights
uncommon now in all those uses, because e.g. LED is more efficient than incandescent
E39/E40 (giant/'mogul') in industrial / older stage lighting


See also: http://en.wikipedia.org/wiki/Edison_screw#Fittings

bi-post / bi-pin

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Many bi-post are IEC 7004 (verify)

You may like overviews from image searches for terms like light bulb socket types diagram


The number specifies the pin distance. Each distance tends to have a unique socket/plug design, in part to make them more easily identifiable.


GU10 (230V MR16), GX5.3 (12V MR16 bulb)
G9 with its loops

Variants with smaller distances are typically small spots (classically halogen), for example:

  • GU10 - pins, 10mm distance, widened bayonet-style end (seems to be one of only a few G variants that has that bayonet)
  • GX5.3 - pins, 5.33mm distance
  • G4 - pins (4mm distance, thinner)
  • G9 - flat loops, 9mm between the centers of the loops

These may be easy to find in supermarkets and such - though the exact set varies a little with where you live.




Larger variants like

  • G23 and G24 are used in office lighting.
  • G53 is used e.g. in larger PAR spots



A few further details/associations are specified by the letters, e.g. G, GU, GX, GY, GZ.

For example, GZ bulbs use dichroic glass, which dissipate most of the heat so lets out most of the heat at the back.

Power and beam angle may wel be specified [1] though have some inconsistencies in specification.


While endless combinations between socket, bulb, and voltage could exist, there is a lot of consistency in what is actually produced, so in practice most most further details are (only) implied from most specific references being unique(verify).

For example:

  • GU4 are often 12V MR11 bulb
  • GU5.3 are often a 12V MR16 bulb
  • GU10 are often mains-voltage MR16 (as are various others with >7mm pin spacing)
GZ10 is like GU10 but does not have a beveled base, which means you can't use GZ10 in GU10 sockets (but can the other way around). The reason seems to be a heat/safety restriction: GU reduces heat to to the rear/socket, GZ does not.
  • G6.35 (1mm thick pins)
  • GY6.35 (1.25mm thick pins)
  • GY6.35, G8, or G9 are more frequently JCD type.
G9 is often mains, G6.35 is often low-voltage



JC, JCD

Refers to a shape - just the small halogen bulbs, no reflector. Can be 12V, 24V, or mains voltage.

Comes in a few base sockets, often one of G6.35, G4, G8(verify)

Apparenly frequently semi-permeable glass, which is why you shouldn't touch it with your oily fingers.


MR, Multifaceted Reflectors

MR (e.g. in MR11, MR16) refers to a Multifaceted Reflector, which produces a more focused beam than simple parabolic reflectors. (see also PAR, which is more specifically an anodized reflector)

MR bulbs are mostly associated with G-style bases, including GU10, GX5.3, and G4.


The number in MRsomething is the bulb diameter - in eighths of an inch, so MR16 bulbs are 5.1cm in diameter, MR11 are 3.5cm.

The combinations of diameter and socket aren't unique - which means it's fairly easy to walk into a store and buy a MR16 and discover you needed one with a GU10 and GU5.3 base and got the other.


You sometimes see specifications of diameter as well as power and beam angle - see [2].



On voltage

Different MR bulbs may be 12V (most) or higher voltage (some), so never blindly assume.


12V may still be AC, though are often DC in practice.(verify) LED-based MR-series often won't care since they need to rectify anyway.

Some of the 12V (switch-mode) adapters designed for a string of halogen MRs will not like the low power draw of LED variants. You need a transformer that is not trying to be clever, one designed for lower draw, attach more lights on a single adapter, or get one designed with LEDs in mind.



Other notes

See also DIY_optics_notes#Stage_lighting.


See also

Other notes

On angle

See e.g. DIY_optics_notes#PAR_spot


"You shouldn't touch lightbulbs"

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Yes, but only really for halogen bulbs, and then only a subset of them.


In the realm of lightbulbs, halogen bulbs are one of a few that specifically uses quartz glass, because quartz can deal with higher pressure and temperatures.

Note that some quartz designs don't need to, or use an additional regular-glass envelope around the quartz envelope (in part to protect against large temperature differences), in which case the below doesn't apply.

Apparently applies less to a lot of professional high-powered lighting, in that much of that uses hardglass.

But unless you can reliably tell, it's good habit / rule of thumb to not touch anything that looks halogen.


When using quartz glass, there are two extra things that can happen.

One is devitrification, a change of the crystal structure from a more random to a more crystalline form. In glass this happens more easily with higher temperatures, and/or when there is a nucleation center for a crystalline structure to start growing, which happens more easily when there are surface impurities.

Because of crystal properties of clear quartz, this will easily make it look cloudier, which is not very useful in a lightbulb.

Devitrification by itself barely affects bulb life, though.


The fat and protein from your fingers could create hot spots - which puts a temperature differential and thereby the amount of stress while it heats, probably breaking it sooner, sometimes much.

In theory, a little oil may just burn and sputter off soon enough - it's more that in some cases it could sort of etch itself in.