Discrete Optoelectronics

Light emitting diodes were developed as a cheap, reliable solution for both indicator lamps and character displays, and were compatible with the rapidly evolving transistor technology of the 1960s. Pioneering LED manufacturers include General Instrument, HP, Monsanto and Texas Instruments.

AT&T ODL50
 AT&T ODL50

Devices included in this entry:

AT&T ODL50 TX 1252P transmitter (16-pin custom DIP; pictured in thumbnail)
AT&T ODL50 TX 1352P receiver (16-pin custom DIP; pictured in thumbnail)


The AT&T ODL50 Optical Data Link is a 50Mbps transmit/receive device pair designed for intrusion resistant, high reliability data communications for military and industrial applications. Both devices contain a CMOS integrated circuit which performs the data-handling functions, and are packaged in a gold-plated DIP package with an integral heatsink.

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CEMI CQYP 32A & CQDP 40
 CEMI CQYP 32A & CQDP 40

Devices included in this entry:

CEMI CQYP 32A LED indicator (pictured in thumbnail)
CEMI CQDP 40 LED indicator


The CEMI CQYP 32A and CQDP 40 are Polish-made 4mm LEDs which appear externally identical to the Monsanto MV1, but are internally more similar to a modern LED. The dies appear to be standard GaP and GaAsP construction from the 1970s or 1980s, and are mounted in a typical small reflector cup. Also unlike the MV1, the CQYP 32A and CQDP 40 have a tinted epoxy which matches their indicator color.

Special thanks to Zygmunt Flisak for identifying these obscure devices.

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Fairchild FLV-10x Series
 Fairchild FLV-10x Series

Devices included in this entry:

Fairchild FLV101 LED indicator (pictured in thumbnail)
Fairchild FLV102 LED indicator


Fairchild's first LED, the FLV-100, was a primitive 500ucd device intended as a fiber optic point source. As the FLV-100 made a poor lamp, Fairchild introduced the FLV-101 and subsequent FLV-102 to address the emerging LED indicator market. The FLV-101 has a diffuse lens to increase visibility and create a wide viewing angle. The subsequent FLV-102 has a less diffuse lens with a 30 degree viewing angle, and omits the vestigial third lead of the FLV-101, a remnant of its TO-106 ceramic transistor packaging. Both the FLV-101 and FLV-102 are brighter than the FLV-100; the FLV-102 is rated at 1mcd.

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Hewlett-Packard HEDS-1000 & HBCS-1100
 Hewlett-Packard HEDS-1000 & HBCS-1100

Devices included in this entry:

Hewlett-Packard HEDS-1000 optical reflective sensor (8-lead TO-5 metal can; pictured in thumbnail)
Hewlett-Packard HBCS-1100 optical reflective sensor (8-lead TO-5 metal can)


The Hewlett-Packard HEDS-1000 is a high resolution optical reflective sensor designed for various functions such as bar code scanning and edge detection. The HEDS-1000 contains a 700nm GaAsP point source and a transistor-amplified photodiode detector, mounted under a translucent red bifurcated aspheric lens. The lens images the active areas of the emitter and detector to a 0.19mm spot located 4.27mm in front of the package window.

The HBCS-1100 is identical to the HEDS-1000, but has a higher brightness LED point source, which results in a higher detector photocurrent and improves the reflected photocurrent to internal stray photocurrent ratio.

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Hewlett-Packard HLMP-DB00 & HLMP-DB15
 Hewlett-Packard HLMP-DB00 & HLMP-DB15

Introduced in 1993, the Hewlett-Packard HLMP-DB00 and HLMP-DB15 are among a small number of commercially produced silicon carbide (SiC) blue light emitting diodes. The two devices appear to be internally identical, the only difference being that the -DB00 has a slightly milky, diffuse lens, while the -DB15 is water-clear.

Hewlett-Packard HLMP-DBxx Series Datasheet

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Monsanto MV1
 Monsanto MV1

Introduced in 1969, the Monsanto MV1 is generally considered to be the first commercially viable visible LED. Unlike modern LEDs, the MV1 is packaged in a gold-plated metal canister with an epoxy lens. The MV1's internal construction consists of an 'anvil head' contact surface, upon which a square GaAsP die with a circular aperture is mounted. Like other early LEDs, the MV1 is an extremely dim device, only barely visible under indoor lighting.

Monsanto later introduced the MV2, a GaP green device.

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Motorola TO-92 Package LED
 Motorola TO-92 Package LED

This device is a mundane red LED die in a highly unusual translucent red TO-92 transistor package. Electronics lore states that Motorola made these parts-of-questionable-judgment under contract for use in camera rangefinders. The existence of such a device stands as a depressing reminder that, at one point in the not-so-distant past, it was actually economically viable to increase the gold content of your product by 50% if it would allow you to avoid changing your package tooling.

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Nichia NSHU550E & NSHU590E
 Nichia NSHU550E & NSHU590E

Devices included in this entry:

Nichia NSHU550E UV-LED (2-lead TO-46 metal can with flat window; pictured in thumbnail)
Nichia NSHU590E UV-LED (2-lead TO-46 metal can with spherical lens)


The Nichia NSHU550E and NSHU590E are the first commercially available UV-LEDs, featuring a 370nm peak wavelength and 1mW output. The NSHU550E and NSHU590E differ only in their optics: the NSHU550E has a flat glass window, while the NSHU590E has a spherical glass lens. The addition of a lens gives the NSHU590E a narrow beam output, but also reduces the diode's raw output power from 1mW to 0.75mW. These devices originally sold for over $30 each in 2001, when they were first being produced.

Nichia still manufactures improved versions of the NSHU550 and NSHU590, rated at up to 2.5mW output.

Roithner Lasertechnik NSHU550E Datasheet
Roithner Lasertechnik NSHU590E Datasheet

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Proton KIPD73A
 Proton KIPD73A

The KIPD73A is a Soviet-manufactured 12x12mm green LED prototype, produced at the Proton plant in Orel, Russia. This LED has a large water-clear bubble magnifier, heat-staked to a 10x10mm gold-plated heatsink. The die is mounted in a recess at the center of the heatsink. This device is notably brighter and of higher quality construction than most Soviet LEDs, but is still quite dim relative to its apparent thermal dissipation requirements.

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Soviet 2L101B
 Soviet 2L101B

Possibly the most primitive production semiconductor ever manufactured, the 2L101B is a rare Soviet military silicon carbide LED. The 2L101B consists of a silicon carbide die, sandwiched between two leads and packed in a minuscule droplet of glass. This device has a slightly greenish yellow glow compared to conventional GaAsP yellow LEDs, and is incredibly dim.

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Soviet AL102A
 Soviet AL102A

Much like other Soviet production LEDs such as the 3L341V, the AL102A is a dim red GaAsP device packed in a metal canister, with a clear lens which affords a direct view of both the emitter die and and various manufacturing contaminants. The AL102A is rated at a brightness of 0.4mcd.

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Soviet 3L341V
 Soviet 3L341V

The 3L341V is the de facto example of a Soviet-made LED. Manufactured in 1989, the 3L341V appears to be of standard GaP green chemistry, but is encased in a 1970s-style metal can package with gold leads. The included datasheet indicates that they emit no less than 0.15 microlumens Needless to say, you won't need special eye protection to handle them.

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Western Electric 530A
 Western Electric 530A

Introduced around 1975, the Western Electric 530A is an unusual epitaxial GaP red indicator LED with square wire wrap pins. Western Electric also manufactured the 530B, externally identical to the 530A but with a green output.

Western Electric 530A, D & G Datasheet

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Western Electric AC LED
 Western Electric AC LED

The Western Electric AC LED has two green dies of opposite electrical orientation, wired in parallel. The LED is normally operated at 60Hz, installed in a Western Electric Trimline telephone handset. This device has an unusual concave lens and large heatsink leads.

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Western Electric Green LED (Unknown P/N)
 Western Electric Green LED (Unknown P/N)

This green LED was used in telephone handsets and other equipment manufactured by Western Electric in the 1970s. Unlike the LED used in Trimline telephone keypads, this is a single-die DC-driven device. The construction style appears similar to that of the Western Electric 530A, but in a much smaller package. Like many Western Electric components, this LED is a robust device with large square wire wrap pins. This type of LED was also available with a red emitter.

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Early Red LED (Unknown Mfr.)
 Early Red LED (Unknown Mfr.)

This LED closely resembles a Monsanto MV1, but has a barely translucent red epoxy diffuser. The manufacturer and part number of this device are currently unknown.

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Flat Top LED (Unknown Mfr.)
 Flat Top LED (Unknown Mfr.)

This unusual LED point source, possibly manufactured by Phillips, appears to be a fairly standard GaAsP red emitter with a minimal epoxy coating protecting the die and bond wire.

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Green Epoxy GaAsP LED (Unknown Mfr.)
 Green Epoxy GaAsP LED (Unknown Mfr.)

This strange device is exactly what it appears to be: a standard GaAsP red LED in a standard 5mm green epoxy case. It is unknown whether this device is a manufacturing error, a failed attempt at producing a new color or some sort of marketing trick. The device produces a pure red light, only slightly dimmed by the green lens.

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N6L 002 (Unknown Mfr.)
 N6L 002 (Unknown Mfr.)

The N6L 002 is another device which emulates the basic Fairchild construction method, sharing a modified TO-106 package style with the FLV-102. The N6L 002 abandons the epoxy lens of the FLV102 in favor of a glass lens, and is also much brighter.

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