Looking for a specific LED

[Dave McGuire]

On Nov 29, 2009, at 8:50 PM, Brent Hilpert wrote:
>>>>> Stamped around the base is "842","M" & "701".
>>>>
>>>>    Monsanto MV2s.  Beautiful devices.
>>>
>>> (Minor correction to my own msg: "1842" instead of "842".
>>> Probably the IBM part number.)
>>>
>>> Are they so unique to id them as MV2s?, I think HP was using a
>>> similar package.
>>
>>    I have a handful of MV2s from my childhood days.  I've never seen
>> another LED quite like them.  There wasn't a whole lot of package
>> standardization (some, but not much) for LEDs in those days.
>
> This page suggests they were from HP, the 1842 part of the number  
> matches.
>   http://www.decadecounter.com/vta/tubepage.php?item=39&user=0
>   http://www.decadecounter.com/vta/articleview.php?item=525

   I agree; that stamped number cannot be a coincidence.

> The top contact on the ones I have is the star as shown there,  
> rather than the
> simple circle of the MV2.
> Something similar also shows up in the 1976 HP Optoelectronics  
> databook.

   Excellent.  This suggests that the small handful of these  
components that I have are  in fact a mix of HP 1842-7329 and  
Monsanto MV2 LEDs!  I have about 50/50 with and without that "star"  
top contact.

> The MV2 is further down the page; looks the MV2 is more significant
> historically.
> Also for the MV2: http://ledmuseum.home.att.net/1960.htm

   That is a fantastic web site...I lost several hours to it  
yesterday.  Further down that page, the 3L341V (which is almost as  
aesthetically pleasing to me as the MV2!) is an LED that I have  
several of; I bought them from a surplus dealer a few years ago.  I  
think I have about twenty of them.  They're really great looking  
LEDs.  I also have a few of the Western Electric dual-chip LEDs that  
are a bit further down.

              -Dave

-- 
Dave McGuire
Port Charlotte, FL