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Don Klipstein's Lighting Info Site!

Updated 10/18/2017.

The most efficient and brightest LEDs! (updated 10/18/2017)

The most efficient colored LEDs have overal luminous efficacy of approx. 70-170 lumens/watt at "full power". The most efficient white lighting LEDs at "full power", or even at any datasheet characterization current, in "real world practical" thermal conditions, achieve around 120-205 lumens/watt as of 7/18/2016 - 1/28/2017. Cheaper ones used in some flashlights sold in late 2013 achieved 30-40 lumens/watt.

For comparison:

"USA-usual" (now banned to manufacture in or import into USA) 100W 120V "A19" 750 hour incandescent - 17.1 lumens/watt. Lower wattages and longer lifetimes achieve less, mostly 10-16 lumens/watt. The halogen replacements have efficiency of 20.7, 19.8, 17.4, and 12-15.2 lumens/watt for 100W, 75W, 60W and 40W replacements respectively.
Compact fluorescents - mostly 45-65 lumens/watt including ballast losses, maximum in sub-45-watt range is 70 as far as I know.
32 watt T8 fluorescent in "average condition" - typically around 80 lumens/watt including ballast losses.

The most efficient LED incandescent-replacement light bulbs that I have seen in retail stores achieve 115-123 lumens/watt but few exceed 94 lm/W.

My LED top page, with links to manufacturers, etc. Updated 8/14/2017, external links noted to be updated 10/6/2016.

My page on LEDs that work usefully at low current of .04-3 mA. Updated 9/5/2015.

My page explaining where some big claims of LED efficiency come from, including applications where they are better at outperforming other light sources in efficiency. (updated 5/30/2016)

The Great Internet Light Bulb Book, Part I - Incandescent and Halogen Lamps
An FAQ style "encyclopedia" with answers to most of your questions and other interesting and possibly helpful information.
(Last major change April 1996, minor change 5/29/2006)

Compact Fluorescent Lamps - RESTRUCTURED 5/11/2009 - please see my Compact Fluorescent "Top Page" for links to my compact fluorescent pages. Updated 5/30/2010 (with news of one of the few dollar store models that don't outright rot). NEW NOTE 2/2/2017: LED light bulbs are now more economic and better than CFLs for most purposes. An LED light bulb page is coming here soon!

The USA federal incandescent lightbulb ban of 2012 to 2014 -
Including the wide range of exemptions.
(updated 1/2/2012)

NEW 2/15/2010 - s/p ratios of many light sources! (Updated slightly 2/27/2016)

Colors and spectral characteristics of fluorescent lamps.
Includes colored, specialty, UV, and white / whitish fluorescent lamps.
(updated 12/6/2006.)

The Discharge Lamp Article (Great Internet Light Bulb Book, Part II - Discharge Lamps, Volume I - Basic Info) is now here.
Lots of useful information about mercury, sodium, and metal halide lamps as well as "neon" signs and tubing is already here.
(update 12/28/99 V. 1.34)

Some more technical discharge lamp info including references is here! (Possibly A.K.A. The G.I.L.B.B, Part II, Volume II.) First written May 23, 1996 and nowhere near complete.
(Expanded slightly 8/19/2002)(28K)

Some bits of data and facts on some lamps and lighting, mostly but not entirely moderately technical, such as incandescent lightbulbs lasting a century, where to buy these, lower energy efficiency of longlife incandescents, and why higher wattage incandescents are more efficient and why lower wattage incandescents are often made to last longer. Updated slightly 1/14/2011.

Some bits of data and facts on some lamps and lighting, more technical, such as bulb surface temperatures, fixture heating, and number of lumens in a watt of white light. Updated slightly 4/4/2015.

The Sulfur Lamp Document
Much of the knowledge of these lamps that you will find anywhere on the web. (Updated 3/24/98)

Lots of fluorescent lamp stuff by Sam Goldwasser and myself. Includes some info on fluorescent blacklight and other UV lamps, even fluorescent-style germicidal lamps.
(slight update V. 1.90 12/26/99) (long, 99K)

Dimming Fluorescent Lamps! Why it's easy to dim them a little, and why it takes a lot to dim them a lot, especially in a way that is not hard on the bulb. Also a few loopholes.
(updated 6/67/2001)

Electronic ballasts! Lots of links, especially for powering fluorescent lamps from low voltage DC. A bit on-site, including a way to power mercury lamps from low voltage DC (built and tested). Links include electronic ballast stuff in general including line powered ballasts. (updated 12/11/2006)

Now, a UV and UV lamp document! Includes EPROM erasing lamps and (roughly) effectiveness of alternatives. Also includes notes on blacklights, sunlamps, and other UV lamps.
(Updated 11/16/2006.)

Carbon arcs for fun and danger!
Some basic info about carbon arcs. For information and your web reading pleasure! These have hazards, and you might not want to try this at home.
(Last change 9/24/96)

Short Arc Lamps - you're wondering about these? They have a small, very intense arc in mercury and/or xenon. Due to high cost, short life expectancy, hazards and often fussy operating requirements, they don't make good toys for casual experimenters. Some of the messy details are here!
WITH MANUFACTURERS, updated 3/1/2010

Xenon flashlight lamps / bulbs and others that are actually incandescent ones with a xenon gas fill. Updated 10/5/2000.

Some odd lamps desribed here including how to make them work. Green "neon" lamps, multicolor "neon" tubing, electroluminescent lights, and spectrum tubes are mentioned here in great detail. Look for more here in the future! (updated 4/26/2008)

I have tested some night lights and lower wattage energy saving odd sorts of lights - and at times I was disappointed. Go to my Night Light Test Results Page to find out how some are less than they lead you to think that they are. (Updated 3/29/2011)

Where to get lamps / lightbulbs!
Get decent plain ones for less, get UV lamps and specialty ones. Info on retail chains in the USA and a few suppliers with web sites.
(Minor update 10/5/2017)

Troubleshooting things that go wrong! Lightbulbs burn out too quickly? Fluorescent lamps acting up? Look here! (updated 11/20/2006)

My top page for all my xenon stuff such as strobes, flashes, xenon arc lamps, strobe hacking, etc. (updated 7/23/2011)

Automotive HID lamps, AKA xenon headlights, etc. New file 2/15/2000 updated slightly 12/3/2011, not much since 2000.

Electrical characteristics of HID lamps for experimenters, hackers, ballast homebrewers and basement bombers. Includes normal operating arc voltage, minimum arc voltage during warmup, starting voltages, and allowable warmup currents for many popular HID lamps.

My discussion of low wattage HID lamps - why there is no 5 watt or 1 watt HID lamp. (updated slightly 3/23/2009)

How long can a lightbulb last? How easily can they be made to last longer? Why they don't? (updated 4/13/2010)

updated significantly 4/30/2012.

Performance of incandescent lamps at various voltages. So far, current, color temperature and light output as a function of voltage for the 100 watt 120V 750 hour 1750 lumen A19 as well as current as a function of voltage for vacuum T12 and gas filled A19 25 watt 120V lamps. New file 1/2/2006, major update 12/29/2006, minor update 1/16/2011.

Please read my Copyright Info and my Disclaimers.

Links to other sites I consider worthwhile:

A notable light bulb collector's site at clubsilicon.com. Shows photos of a variety of lamps, even short arc and deuterium. With a link to the Modern Light Bulb Collector's webring.

A notable piece of light bulb history online at the notable Kilocat's Antique Light Bulb Site, which now even has a forum!

James Hooker's Online Museum of Historic Discharge Lamps

Daniel Stern's automotive headlight site.

JKL Lamps, a maker of miniature cold cathode fluorescent lamps and other miniature lamps.

Tomi Engdahl's Lights and Electronics Page.

Philip G. has lots of stuff, much is interesting! NOTE - This site is supposedly being decommissioned and most of the info there is now available at http://www.repairfaq.org/

The Lighting Resource has some interesting and maybe useful information, including a large list of links to lighting related manufacturers, wholesalers, retailers, and other lighting related sites.

Another good site with lots of links! Lots of basic and moderately advanced info.

Another route to this page.

The site of Ioannis Galidakis, with spectra stuff!

The Lightbulb section of Jim Evan's home repair site.

Electric Lights - the site of a fellow light bulb nut, Chris Millinship in England.

Sylvania's lighting site. Great site, with an online catalog and brief sheets of probably thousands of lamps.

Philips Lighting, with an online catalog.


American Light, which supplies many kinds of specialty and custom fluorescent, mercury, and metal halide lamps

The Lighting Research Center at Rensselaer Polytechnic Institute.

Another large list of mostly entertainment-related lighting links, in Australia.

An interesting web page by the Lamptech.co.uk largely-an-online-museum that in that page appears to me to promote and to be somewhat biased towards low pressure sodium lamps. There is an interesting graph showing current and historic maximum commercially successful lamp luminous efficacy over the years for several different lamp technologies.

The Lamptech home page.

FX Lighting.

As for references for lighting related stuff, I learned a good portion of what I know from books with Library of Congress call numbers around TK4000.

I appreciate feedback. Go ahead and drop me a line! I read all non-"SPAM" e-mails, but sorry I can't reply to all legitimate e-mails!

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