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Circuit design for a 1W LED lamp project
This circuit prototype uses a rather uncommon but brilliant design that combines both simplicity and efficiency! (At least when power factor isn't considered). More details about this project [url=https://sites.google.com/site/vinceelectriclaboratory/home/homemadeledlamps1st]here[/url].

Instead of using a 3W resistor to limit the current I'm going to use a X2 class capacitor from an old power supply to limit the current by capacitive reactance to ~11mA. PF is horrible (22%) but even then this design remains twice more efficient than using a 3W resistor!

The final lamp is going to have 20 LEDs, but I only have 9 in stock at the moment LOL.
Keywords: Gear

Circuit design for a 1W LED lamp project

This circuit prototype uses a rather uncommon but brilliant design that combines both simplicity and efficiency! (At least when power factor isn't considered). More details about this project here.

Instead of using a 3W resistor to limit the current I'm going to use a X2 class capacitor from an old power supply to limit the current by capacitive reactance to ~11mA. PF is horrible (22%) but even then this design remains twice more efficient than using a 3W resistor!

The final lamp is going to have 20 LEDs, but I only have 9 in stock at the moment LOL.

102_1331.JPG 102_1314.JPG HPIM1369.JPG CGE_F26T8-CW_X3.JPG 102_1307.JPG
File information
Filename:HPIM1369.JPG
Album name:Vince / Miscellaneous
Keywords:Gear
Filesize:298 KiB
Date added:Apr 05, 2014
Dimensions:2000 x 1500 pixels
Displayed:274 times
Color Space:sRGB
Contrast:0
DateTime Original:2014:04:05 15:29:20
Exposure Bias:-1 EV
Exposure Mode:0
Exposure Program:Program
Exposure Time:1/30 sec
FNumber:f/3.6
Flash:No Flash
Focal length:7.5 mm
ISO:257
Light Source:Unknown: 0
Make:Hewlett-packard
Max Aperture:f/3
Model:HP DVC V5061u
URL:http://www.galleryoflights.org/mb/gallery/displayimage.php?pid=17274
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Comment 1 to 10 of 10
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streetlight98   [Apr 06, 2014 at 04:26 PM]
Nice! Really cool project. I wonder if white LEDs will be better than the red. There are some old incandescent exit signs at my school and the whole front is a white diffuser with EXIT painted in red letters. and they used RED LED RETROFITS! So the face of the exit sign is just a red blob that barely glows. I think if they were going to go LED, at least use candelebra LEDs for chandeliers. At least you'll get the right color and they'll be a little brighter than these foolish things my high school used.
joe_347V   [Apr 06, 2014 at 05:55 PM]
Nice project!

@Mike, your school schould have used this instead lol.
lite_lover   [Apr 06, 2014 at 08:08 PM]
Cool project Vince. Cool
TiCoune66   [Apr 06, 2014 at 09:01 PM]
Mike: Probably not xD But the challenge with this project is to use as many salvaged components as possible. I don't have that many red LEDs (bright ones, that is), but I do have a bunch of white ones LOL.

Weird, those retrofit lamps you linked are usually pretty good. I have a few pictures of exit signs with horrible retrofit lamps, transparent tubular ones with little 3mm LEDs.
streetlight98   [Apr 06, 2014 at 11:54 PM]
@ Joe; Yeah they would have worked better lol.

@ Vince; The retrofits work but they're so dim. On a sunny day and when all the hallway lights are on (sometimes every third light is off for whatever reason lol) you can't even tell the signs are lit. Plus a good portion of the exit signs at my school look like this one here. As you can guess, the red light behind the face makes the EXIT face illegible so it's actually even harder to read. I don't know how they even pass fire code.

The Cranston Public Schools is trying to get a $15 million grant for the schools and half of that will be getting the schools up to fire code. So if the exit signs aren't up to par they'll probably just replace them. And since it's a grant they'll smash up the old exit signs even though they're probably worth a hundred bucks each and I'd probably kill somebody to get my hands on one lol.
rjluna2   [Apr 07, 2014 at 12:37 AM]
Nice project, Vince Smile
TiCoune66   [Apr 07, 2014 at 12:47 AM]
Ah, the fire code! The school I'm going to at the moment is FAR from being up to code as well! A bunch of ionization smoke detectors are almost 30 years old, they should've been replaced since the early 90s, and again in the 2000s. And AGAIN in the last few years! xD

When it comes to exit signs it seems everyone maintains them their own way LOL. I've seen some very well maintained and regularly relamped, others not taken care of at all! In my school again, I know a few exit signs that never got relamped since my first day in that building, in 2010! But that building's exit signs aren't the best maintained anyway LOL.
streetlight98   [Apr 07, 2014 at 01:47 AM]
my elementary school was the only school that didn't have LEDs when i was at it. It had two lamp PL5s or PL7s in each exit sign. I loved the buzz from them. It seemed one always had a stuck starter somewhere in the building and would do that non-stop flicker thing lol. Normall they'd wait for both lamps to EOL before replacing the lamps. Sometimes they fixed the sign if only one lamp was out, probably if they knew an inspector was coming lol.

as for my middle school, i actually forget what kind of exit signs they used. I know they were LED though and they must not have been very attention-worthy or I'd remember them more lol.

Some parts of the school that were added in the 90s have plastic LED exit signs and I SWEAR they don't light up. I bet they were brighter when new but you seriously cannot tell they're lit unless you really study them closely. Some have missing front covers too so it's just an open box with a faint red light lol. They replaced one exit sign in the gym that was victim to a ball I suppose and it's nice and bright! though it too has no cover and simply has an array of red LEDs on the bottom inside of the sign. At least you can see that it's lit lol.

I'd sure like to see your concept put into use. My guess is that red and blue LEDs are the cheapest and that's why they're used instead of white. (i heard green exit signs actually use blue LEDs, but have only ever seen red exit signs except for the green edge-lit signs at the Showcase near me).
A_lights   [Apr 07, 2014 at 03:50 AM]
those Plastic cooper LED fixtures are garbage, after a decade the red LEDs dim out so bad that they're not visible with store lighting on, but if you open them up they are lit so should be visible if power went out since the battery is still good in most units, we change the dead batteries too
streetlight98   [Apr 07, 2014 at 11:05 AM]
I don't know if the batteries are still good in the units but they at least have batteries lol.

Comment 1 to 10 of 10
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