clinton writes:
<< You can take 100 OM-1/1n's of the same vintage, check the values of the
resistors, and you'll discover they're all the same from camera to
camera to camera!
>>
Hi Clinton,
you may well be right that similar vintage cameras have tight
tolerance cells, particularly within a manufacturing batch.
In my limited look at this when I was modifying OM1 circuits for silver oxide
battery use, the three examples I looked at, spaning a wide date range
(OM1,OM1MD,OM1N) all had somewhat different values and in at least one case a
different number of resistors as one of the resistors is optional (infinite
value!) in the circuit.
Most catalog CDS cells have a fairly loosely specified tolerance although the
requirements for photo use are rather loose too. (1/3 stop is a large %)
For example Silonex a current US domestic producer has most of it's standard
product with 33-40% tolerance specs see:
http://www.silonex.com/optoelectronics/optophotoc.htm
The small print on the specs is also interesting: a mionimum of 16 hour
light soak before testing the cell!
Regards,
Tim Hughes
>>Hi100@xxxxxxx<<
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