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Subject: pH meters

pH meters

From: Walter Henry <whenry>
Date: Tuesday, March 7, 1989
Im also not certain whether crossing brands is problem free (ie corning
or beckman electrode with an orion meter.  but Im pretty sure that if
the plugs fit it should work.  someday we'll have a few scientists
available (they are *all* probably somewhere on the net (well, many
anyway, such as the people at carnegie if only we knew how to get to
them.  eventually...

ok here is the straightest of straight: I phoned ralph roessler, my
engineer friend at pti:

re: knobs versus buttons: in very dirty environments knobs may be better
than buttons, because they may have brushes that clean the connection
every time you turn them.  in a clean environment, which one assumes
your lab is, it shouldnt make any difference (dirty in this context
means things like aboard ship, out at an archeological site, etc).

re: analog versus digital: in high end instruments, analog may give
higher accuract (or perhaps it was precision, I forget (but Im pretty
sure it was accuracy) because they have a higher sampling rate. this is
not simply for ph meters but many kinds of electronic instruments (he
gave an example of miltimeters which to match the best analog
instruments you need to spend twice as much with a digital instrument).
however, for the price range we were talking about ($500) this does not

this is all opposite of what I imagined, so I am chastened.

                  Conservation DistList Instance 2:12
                  Distributed: Sunday, March 12, 1989
                        Message Id: cdl-2-12-003
Received on Tuesday, 7 March, 1989

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