RED 640-700nm


Spectrum of a typical 660nm red LED.

Radio Shack # 276-0307 High-Brightness Red LED, $1.99
Purchased 04-05-09, tested on 06-06-09
This is a 5mm red LED in a water-clear epoxy package.


Beam photograph on the test target at ~12".


Measures 2,700mcd on a Meterman LM631 (now Amprobe LM631A) light meter.


Viewing angle is listed as 12°.

Mr. Meter sez Vf is 1.811 volts at an If of 19.28mA.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.


Beam cross-sectional analysis
Beam cross-sectional analysis.
Image made using the ProMetric System by Radiant Imaging.




Radio Shack # 276-0086 10mm Red LED, $2.79
Purchased 05-03-09, tested on 05-26-09
This is a 10mm red LED in a water-clear epoxy package.


Beam photograph on the test target at ~12".

Measures 4,444mcd on a Meterman LM631 (now Amprobe LM631A) light meter.

Viewing angle is not listed, but appears to be ~12°.

Mr. Meter sez Vf is 1.918 volts at an If of 19.28mA.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.


ProMetric analysis
Beam cross-sectional analysis.
Image made using the ProMetric System by Radiant Imaging.




Radio Shack # 276-0015 10mm Red LED, $1.79 (package of 2)
Purchased 04-26-09, tested on 04-29-09
This is a 10mm red LED in a water-clear epoxy package.


Beam photograph on the test target at ~12".

Measures 1,610mcd on a Meterman LM631 (now Amprobe LM631A) light meter.

Viewing angle is listed as 16°.

Mr. Meter sez Vf is 1.003 volts at an If of 19.28mA.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.


ProMetric analysis
Beam cross-sectional analysis.
Image made using the ProMetric System by Radiant Imaging.




Radio Shack # 276-0307 High-Brightness Red LED, $1.99
Purchased 03-29-09, tested on 04-01-09
This is a 5mm red LED in a water-clear epoxy package.


Beam photograph on the test target at ~12".


Measures 2,700mcd on a Meterman LM631 (now Amprobe LM631A) light meter.


Viewing angle is listed as 12°.

Mr. Meter sez Vf is 1.811 volts at an If of 19.28mA.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.



Radio Shack # 276-312 Red Blinking LED, $1.99
Purchased 03-29-09, tested on 04-01-09
This is a flashing red LED in a standard 5mm water-clear epoxy package.


Beam photograph on the test target at ~12".
Unable to measure intensity or If (forward current) because this is a blinking lamp


WMP movie (.avi extension) showing the LED blinking.
This clip is approximately 1.512 megabytes (1,627,530 bytes) in length; dial-up users please be aware.
It will take no less than eight minutes to load at 48.0Kbps.
I cannot provide it in other formats, so please do not ask.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.



Radio Shack # 276-0020 Red High-Flux ("spider") LED, $2.29
Purchased 03-26-09, tested on 03-31-09
This is a red LED in a four-lead high-flux ("spider") epoxy package.


Beam photograph on the test target at ~12".
Measures 1,080mcd on a Meterman LM631 (now Amprobe LM631A) light meter.
This is a wide viewing angle LED (130°), and if I've told you once, I've told you 31,054,500 times:
Wider viewing angles always, ALWAYS, ALWAYS equal lower mcd values!!!

Unable to measure Vf due to how my LED test set was constructed.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.



Radio Shack # 276-0008 Rectangular Red LED, $1.79
Purchased 02-27-09, tested on 03-05-09
This is a wide-angle rectangular red LED in a water-clear rectangular epoxy package.


This is what the LED itself looks like.


Beam photograph on the test target at ~12".


Measures mcd (yes, 3mcd! on a Meterman LM631 (now Amprobe LM631A) light meter.
The packaging materials indicate that this value is 80mcd; perhaps I simply ended up with a bum LED. Just by "eyeballing" it, the intensity does indeed appear to be quite low; I can stare directly into the lamp with no discomfort.

This is a very wide-angle LED; and if I've told you once, I've told you 2,458,770 times:
Wider viewing angles always, ALWAYS, ALWAYS equal lower mcd values!!!
Viewing angle is listed as 154°.

Mr. Meter sez Vf is 1.799 volts at an If of 19.28mA.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.



Radio Shack # 276-0309 Wide-Angle 5mm Red LED, $1.49
Purchased 02-27-09, tested on 03-01-09
This is a wide-angle red LED in a water-clear 5mm "through-hole" (round) epoxy package.


Beam photograph on the test target at ~12".

Measures 750mcd on a Meterman LM631 (now Amprobe LM631A) light meter.

Viewing angle is listed as 40°.


Vf is 1.799 volts at an If of 19.28mA.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 Spectrometer graciously donated by P.L.



http://www.ledsales.com.au..., Nichia 3mm oval red LED (NSPR346CST), retail AU 60¢ (US 55¢)
Received 11-05-07, tested 11-11-07
This is a 3mm oval LED in a diffused, red-tinted epoxy case. It produces a very wide, very smooth beam. The beam is typical for a diffused lens LED lamp.
It is a Nichia NSPR346CST "super oval" red LED.


Measures 880mcd at a drive current of 19.28mA.
Viewing angle is avertised at 110° by 50°
This is a very wide-angle LED; it also has a diffused lens, and if I've told you once, I've told you a million times:
Wider viewing angles always, always, ALWAYS equal lower mcd values!!!!!!!!!


Spectrographic plot
Spectrographic analysis of this LED.




LEDs International, red LED, L15WAR5HP
Received 02-20-07, tested 02-21-07
This is a 5mm round LED in a water-clear epoxy case. It produces a WIDE-ANGLE circular beam; the lens-end is noticeably shorter than the same part on regular 5mm LEDs.


Measures 1,540mcd at a drive current of 19.28mA.
Viewing angle appears to be ~120°.
This is a wide-angle LED, and if I've told you once, I've told you 100 times:
Wider viewing angles always, always, ALWAYS equal lower mcd values!!!!!!!!!


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 spectrometer graciously donated by P.L.




LEDs International, red super flux LED, C1SFWAR25
Received 02-20-07, tested 02-22-07
This is a super flux ("spider") LED in a water-clear epoxy case. It produces a mainly circular beam with an unusually smooth profile for a non-phosphor lamp. Since this is a wide viewing angle LED, the smooth beam was not at all unexpected - most wide angle LEDs will produce smooth beams.


Measures 1,880mcd at a drive current of 70mA.
Viewing angle appears to be ~75°.
This is a wide-angle LED, and if I've told you once, I've told you 100 times:
Wider viewing angles always, always, ALWAYS equal lower mcd values!!!!!!!!!


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 spectrometer graciously donated by P.L.




Manufacturer unknown
Received & tested on 07-03-04
A fan of the website (J.R. in Michigan) sent 11 LEDs (thank you!!!), and five of these red LEDs were among the goods. This is a 5mm round LED in a water-clear epoxy package. I don't know who makes the die (light-emitting chip) inside this LED, so please do not ask, thank you.
I believe this is a 660nm red LED.

The anode (+) connection is on the larger portion of the leadframe assembly inside the LED case, which is opposite of how most other LEDs are.


Measured 1,940mcd with a test current of 26mA, with a Vf of 1.86 volts.
Viewing angle appears to be 30 to 35 degrees; since I do not have the equipment for measuring viewing angles, this is an eyeballed value.



Radio Shack, part # 276-026, price $0.99/package
Received & tested on 02-18-04
This is a 3mm (T1) diffused red LED in a standard epoxy package. What makes this LED different than many other LEDs is that it works exceptionally well at very low currents. One user of this LED reports that he drives it at 0.66mA in a piece of computer equipment and gets an acceptable level of brightness from it.

This LED isn't very bright, so it wouldn't work well for high ambient indicators or in areas where the light must be visible in the sun. But it works very well at lower currents, and can be seen fine in normal room, office, or factory lighting.

According to the back of the package, this LED has the following specs:

Power dissipation: 45mW
Forward current: 15mA

Optoelectric characteristics (at 20mA)

Forward voltage: 3.0V
Luminous intensity: 2.5mcd
Peak wavelength: 700nm

I measured 2.17 volts across this LED with a drive current of approximately 17mA (using a Hosfelt LED Tester with the LED plugged into the 20mA receptacle). So that 3.0 volt figure on the package is a bit high. This LED isn't bright enough to get a picture of its beam. Since this is a DIFFUSED red, the viewing angle/viewability should be very wide. I don't have a lot of information about this LED other than what's on the back of the package, and viewing angle is not among that information.


Since I can't get a beam picture, I took one of the LED itself.
It's the one on the bottom, below the 5mm clear package LED.



Panasonic, model LN21CHP, price & availability unknown
This is an uncommon, but probably not very rare red GaP (gallium phosphide) red LED that comes in a water clear 5mm case. Brightness is low, probably in the 100mcd range, but what's interesting about this LED is its spectrum. Like most GaP reds, this LED has a very distinct and visible secondary band in the green region, as the following spectral image shows:

GaP red spectrum

Although my equipment really isn't set up to do spectral analysis, I did the best I could with a $150 digital camera and a pair of inexpensive diffraction grating glasses from Edmund Scientific's educational materials department. It clearly shows the green in the spectrum. This band does not show up with red LEDs using any other chemistry.

The LED itself is unremarkable, and would suit itself well for use as an indicator or pilot lamp. It isn't nearly bright enough to use for a flashlight or other light source. The lack of red dye in the case makes it possible to obtain the spectral image you see above.



Roithner Lasertechnik, model ELD-700-S24, price TBA
Cherry red Here's an LED with a very odd wavelength, right on the edge
of what is considered to be the visible spectrum.

At 700nm, this device appears to give off a not too bright,
deep cherry red light. This is as red as red gets, folks.

The LED puts out about 13mW, yet because it is all the way at
the end of the visible spectrum, it doesn't look much brighter
than the red indicator lights in your stereo or computer equipment.

At the rated current of 100mA, this LED has a Vf of 2.2 volts.

The viewing angle is quite wide, I'd guess about 60° or 70°.


Roithner Lasertechnik, model SHPL-660, price $35.59
big giant LED This red giant doesn't really even look like an LED, but trust me, it is.

With an optical output of 45 milliwatts at 660nm, it is easily the brightest single LED source you can buy, without having to go the route of buying assembled Prometheus arrays.

This LED has an array of six series-connected AlGaAs chips inside.


Since this LED is so powerful it overloads my new photometer, I measured it using an equally new photometric grade photovoltaic cell provided by Don Klipstein. Using this type of photometer, the LED generated a current of 22.2 mA in the cell, which works out to an optical power of 43.8 milliwatts.



This is one LED you probably don't want to jam in your eye and stare at.
The picture on the left is with 20mA, the one on the right with 100mA.


Spectrographic plot
Spectrographic analysis of this LED.
USB2000 spectrometer graciously donated by P.L.



Radio Shack TLR-147, circa 1980. Obsolete/no longer available through RS.
Here is one of those interesting LEDs that bring back some memories. This red model is packaged up in a custom case with a flat Fresnel lens moulded into it. It was designed to have a very wide viewing angle of 60 degrees or more.
Dim by today's standards, it packs a whalloping 5mcd or so of intensity which was pretty good by mid-late 1970s standards. This red model has an uncommonly broad spectrum even though it is in a red tinted case. Through the scope, it outputs from fairly deep red through orange. Then there's a gap (black area) before another band appears in the green region. It's not every day you see a red LED have an emission band in the green almost as strong as its natural red band.

This LED was designed to operate very well at low current. It continues to light up while other red models tested with it had nearly extinguished due to insufficient forward current.
These LEDs probably had broad applications in all sorts of battery powered equipment back then, when battery power was at a premium and battery technology wasn't what it is today. They aren't very bright, so they wouldn't work well for high ambient indicators or in areas where the light must be visible in the sun. But they work very well at lower currents, and can be seen fine in normal room, office, or factory lighting.

pic of LED
This LED isn't bright enough to get a photograph of its test firing. Note the Fresnel lens-end on this macro picture.


Chicago Miniature, model CMD 53SRC/E (price/availability not known)
This LED is a very wide beam, decently bright model in a clear T1 3/4 case.
It isn't quite as bright as some models I have come across, but is still very reasonably so. It's color is a very slightly orangish shade of red; not quite as orange as the HLMP-DD16 shown on the red/orange LED page. It casts a fairly even, wide 45 degree beam with a less pronounced "hot spot" than most clear LEDs show. It also has a faint corona surrounding the main beam, but because the beam is so wide to begin with, the coronal ring doesn't play a major role in how the beam appears from any distance beyond a few inches.

Through the spectroscope, this one has significant output well into the yellow, but most of it is concentrated in the red region around 640nm or so. If you're looking for a real blinder, you may be disappointed with this model; but it's still plenty bright enough to be seen in direct sunlight and so would lend itself well as a high ambient panel indicator - it may also serve well for use in those lights that people strap on to go out jogging at night.

profile
Beam profile.


Hewlett-Packard, HLMP-C116 (clear, red), estimated $0.40 apiece, Newark Electronics
This is a reasonably bright red LED in the usual clear, T1 3/4 standard case.
It puts out a well-defined beam about 15 degrees wide, surrounded by a fainter but still well-defined corona. A thin outer band appears about 75 or so degrees out from the central beam, and doesn't play a significant role in this lamp's output.

These are reasonably bright, but not anywhere near as bright as the best & brightest models available. They'd work fine in models, as indicators, and in consumer products such as bicycle lights or those lights that joggers wear on their bodies at night. I think the beam may be a little too narrow and their brightness a little on the low side for them to be useful as automotive taillamps, but the color is definately right.

Through the spectroscope, these have one of the narrowest spectrums of any LED tested so far. Most of the output is well into the red, and only a small amount appears in the yellow part of the spectrum. There is absolutely no output in the green, unlike many other red LED models.

profile
Beam profile. The outermost band falls well outside the target area.


Chicago Miniature, model CMD 535RD/G (diffused red), price/availability unknown
Here we have a rather ordinary looking red LED, packaged in a red, diffused case. For all intents and purposes, it looks like your garden variety red LED, packaged up like all LEDs were prior to the introduction of the first really bright models in the mid 1980's. But that's where the similarity ends.

This LED is uncommonly bright for a diffused package model. Its color is a very slightly orangish red, and it is bright enough to cast shadows even several feet away in only mildly subdued room lighting. It produces a very even, diffuse glow; with the brightest portion being around 40 to 50 degrees wide; but casting a visible glow nearly a full 180 degrees.

Fire a couple of these babies up in the kid's room, and they won't need no stinkin' nightlight. And just think of the energy savings over a conventional incandescent type bulb... that is, if you don't mind seeing red.

Use these where you would normally use a diffused lens LED, but beware they are brighter than you might expect.

profile
Beam profile. Notice the nice, diffused beam that covers the whole target.


Hewlett-Packard, model HLMP-8103 (clear, red), estimated $0.40 apiece, Newark Electronics
This lamp is a high-brighness, narrow-beam red model in a clear, T1 3/4 standard case.
It produces a somewhat irregular beam; essentially a bright central square region, surrounded by a dimmer, off-center ring and a somewhat "dirty" and slightly irregular coronal area outside of that. The central beam is around 7 or 8 degrees wide, making this model a true narrow-beam lamp. I am uncertain as to why the beam configuration is so irregular, but a manufacturing quirk or cheap construction may be to blame. The LED itself works fine though, and this should in no way prevent you from using it for anything but the most absolute precision applications.

Use these in models, keychain flashlights, or other applications where a very narrow and bright red beam is desired.

profile
Beam profile.


Radio Shack (bag of mixed parts), 20/$2.49
This is an unusual looking LED, packaged up in a custom case. The case, which is transparent but tinted a deep ruby red, has an inverse conical lens - that is to say it is deeply concave and cut in towards the LED chip in the center, rather than being rounded like a regular LED.

When lit, this LED produces a small spot of a deep red color and has a very wide beam of approximately 100 degrees. It was apparently designed to be visible off to the sides to the same degree that it is visible head-on. The only problem is, it's not very bright at all. Spectrographically, it shows a fairly wide range of colors from deep red all the way into yellow; but most of its energy comes from the red region.

This LED came in a package offered by Radio Shack, which consisted of about 20 mixed, unsorted LEDs of all types and colors. So its origin is unknown, and its intended use is also unknown - I haven't seen an LED of this type in service anywhere in the last twenty years; other than the ones I've ended up with and either lost or installed in hobby equipment. Anybody who's bought Radio Shack's 20 ct. LED grab bag has probably ended up with a few of these.

The one I tested was installed in a toy many years ago; when the toy broke, I cannibalized it for its electronic parts plus the LED I put in it myself. So this LED has just been clunking around in the bottom of a toolbox for who knows how many years before I put this website up.
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ULTRAVIOLET 370-390nm GaN 
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YELLOW 585-595nm
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RED 640-700nm
INFRARED 700-1300nm
True RGB Full Color LED
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