| Monsanto MV4H LED | |
| Written by AnubisTTP on 2019-03-15 |
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30 years before Phillips Lumileds became a household name among semiconductor engineers and flashlight fanatics, Monsanto produced what was likely the first attempt at a high power LED; the MV4 and MV4H. Differing only in the shape of the lens, the MV4 and MV4H try to solve the high output LED problem with comic book logic; take an MV1 and make everything bigger. The MV4H package is approximately twice the diameter of a Monsanto MV1, and contains a similarly engorged LED die. The maximum power rating of this LED is 2 watts; inside the die has been secured with three thick bond wires for increased current capacity. Instead of a pair of leads, the MV4H has a large threaded stud, which is designed to be bolted to a heatsink or other metal object to provide cooling. Due to the rarity of this part we were reluctant to test the MV4H to it's full 2 watt rating, but at 50mA the light output from this LED was "almost usable" ... it is certainly not as bright as even the crummiest mid-1970s 5mm LED, but it can at least be seen in a normally lit room. We have been unable to precisely date the release of this part, but given it's low part number, it seems reasonable to believe Monsanto released the MV4H sometime between 1969 and 1971. The MV4 appears in Monsanto's 1969 price guide with a single unit price of $10.00, but the MV4H does not appear to have been commercially available until at least 1970.
Special thanks to Patrick Hickey for providing this unusual part.
Monsanto MV4H LED, shown next to a MV1 for scale.
The top contact of the MV4H die is connected with three bond wires for increased current capacity.
THe MV4H is much larger than Monsanto's other early offerings, and has a threaded lug to help with heat dissipation.
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