Re: Looking for data on 1980s CDS cells - VACTEK VT212/VT212L

On 2024-09-10 01:55, John Robertson wrote:

On 2024-09-09 9:33 p.m., Chris Jones wrote:

On 29/08/2024 10:19 am, John Robertson wrote:

I'm trying to find a modern CDS cells to replace these old timers (1982) from the 70s, I did find a catalogue page for these CDS cells, but the details are not as useful to me as perhaps they would be to someone handy with using CDS cells.
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The ratings are:
VT212L - 6 R1, 5 R2
VT212  - 7.8 R1, 5 R2
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R1 defined as 2fc resistance in K Ohms (tolerance +/- 33.3% @ 2850K Source
R2 defined as min dark resistance (Megohms) in 5 sec.
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Having a heck of a time matching these to more modern cds such as carried by DK or Mouser. I tried the NSL-06S53, but its light resistance is too sensitive and nothing else on DK was better.
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Anyone have a VACTEK catalogue who could scan the pages that might help?
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I suspect that PerkinElmer bought out Vactek as they used similar part (VT200x) numbers as early as 2001 that I could find on web.archive.org, but that archive doesn't have the parts books captured.
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Bitsavers doesn't list it, nothing on ebay either...
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Why am I bothering? I have a rifle gallery (http:// www.bonanzagallery.com/) that uses flash tubes in the rifles to trip the cds cells in the targets and there are around 70 cds cells. A number of them are failing so I want to replace them with something that will work reliably.
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Thanks as always for your time!
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John :-#)#
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Did you see ths document?:
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https://www.worldradiohistory.com/Archive-Tele-Tech/60s/Electronic- Industries-1965-07.pdf
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Page 84/85 of the pdf, or page 82/83 printed on the original.
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It says
Type VT212
CdSe material
0.62 - 0.86 micron spectral limits (10% points)
0.74 micron peak sensitivity
0.21 inch diameter
0.146 inch depth
 >0.5Meg dark resistance, 25 deg C
7.8kOhm at 2 ft-c T 2850K
50mW dissipation
70 Volt rating
at 0.1 ft-c resistance is 67% of room temperature resistance at 65 deg C
6ms rise time, 5ms decay time at 10 ft-c
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Thanks!
 John :-#)#
 

I have a 1988 Clairex catalog that cross-references the VT212 and VT212L to a Clairex CL903L, which is
6k +- 2k ohms @ 2 footcandles, 40M dark, 100VAC (peak), TO18 case.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
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