PSN-L Email List Message

Subject: Re: Not so simple photoelectrics
From: ChrisAtUpw@.......
Date: Mon, 28 May 2001 21:56:34 EDT


In a message dated 28/05/01, mlamb1@......... writes:

> I'd suspect that any matched cells would have a very high price 
> tag, although I've not obtained any prices.  

       Hammatsu make very good photocells. They are not too expensive 
http://www.hamamatsu.com/ . Silonex look interesting at 
http://www.silonex.com/ . There is also VacTec. I don't know much about other 
US makes. 
The ones I use are made by Siemens BPW34 BPX90 BPX48 etc. The dual BPX48 is 
matched to within 5%. See http://www.infineon.com/products/products.htm

       Allied at http://www.alliedelec.com/default.asp p563 & 565 have quite 
a few suitable products with planar technology. I use BPW34's which are 
similar to the VTD34 980 0150 @ $1.69 that George Harris recommended. I 
bought several cells and found that they all matched to a few %.

       You can get cells half the width and also in pairs on a common 
substrate. You can also get a range of areas from 1 to 100 sq mm. Do not use 
blue enhanced Si diodes. Their sensitivity is MUCH too low (by a factor of 5 
~ 10). The resolution that you can get improves with increasing photo 
current. I use the Mini DIP type cell with a clear moulded case. You do not 
want a lens or even a metal can - the chip is then rather far away from the 
shutter and you get internal reflections since the Mfgrs don't bother to 
blacken the inside of their cans.... The size of the can also prevents you 
placing two chips close together. I have not tried using the coated planar 
chips with connecting wires, but they should be quite OK if stuck onto an 
insulating heatsink with epoxy. A small piece of a black oxidised Al heat 
sink should be fine. A carefully broken new razor blade gives an excellent 
knife edge for the shutter.

   I 
> have some Centronic P/N OSD15-5T photovoltiac 
> cells, but I've no idea of their production quality control or standing 
> 

       Do you have a US Website for these devices please? I do not have a 
reference for -5T devices. Are they metal can types with flat glass covers? 
The Centronic cells that I have used were good.

         Hope that this helps,

       Chris Chapman

In a message dated 28/05/01, mlamb1@......... writes:


I'd su spect that any matched cells would have a very high price
tag, although I've not obtained any prices.  


      Hammatsu make very good photocells. They are not too expensive
http://www.hamamatsu.com/ . Silonex look interesting at
http://www.silonex.com/ . There is also VacTec. I don't know much about other
US makes.
The ones I use are made by Siemens BPW34 BPX90 BPX48 etc. The dual BPX48 is
matched to within 5%. See http://www.infineon.com/products/products.htm

      Allied at http://www.alliedelec.com/default.asp p563 & 565 have quite
a few suitable products with planar technology. I use BPW34's which are
similar to the VTD34 980 0150 @ $1.69 that George Harris recommended. I
bought several cells and found that they all matched to a few %.

      You can get cells half the width and also in pairs on a common
substrate. You can also get a range of areas from 1 to 100 sq mm. Do not use
blue enhanced Si diodes. Their sensitivity is MUCH too low (by a factor of 5
~ 10). The resolution that you can get improves with increasing photo
current. I use the Mini DIP type cell with a clear moulded case. You do not
want a lens or even a metal can - the chip is then rather far away from the
shutter and you get internal reflections since the Mfgrs don't bother to
blacken the inside of their cans.... The size of the can also prevents you
placing two chips close together. I have not tried using the coated planar
chips with connecting wires, but they should be quite OK if stuck onto an
insulating heatsink with epoxy. A small piece of a black oxidised Al heat
sink should be fine. A carefully broken new razor blade gives an excellent
knife edge for the shutter.

  I
have s ome Centronic P/N OSD15-5T photovoltiac
cells, but I've no idea of their production quality control or standing
among other makers.


      Do you have a US Website for these devices please? I do not have a
reference for -5T devices. Are they metal can types with flat glass covers?
The Centronic cells that I have used were good.

        Hope that this helps,

      Chris Chapman

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Larry Cochrane <cochrane@..............>