>From the archives, on Tue, 18 Apr 2000 06:51:16, M. G. Devour wrote (Re: the TDS-1 meter)
> My experience has been that the circuit is stable over time and, if you calibrate it at, say, 50 ppm or so, it will deliver reasonably accurate and repeatable measurements in the range in which we are interested. Sounds like a winner. And just how do I go about calibrating it at, say, 50 ppm or so? Or better yet, at say 10 ppm? What do I use as a standard? Can I use a 1/4 watt resistor to calibrate it? Do I set it to read 50 at 50 ppm or is there a 'k' factor? What is the k? What value resistor ? After it is calibrated, is it in a 1:1k relationship from zero up to 50ppm? Does temperature affect the calibration? My Laboratory is located in an unheated (and uncooled) building that varies from 35 degrees in the winter to about 100 degrees for the next few months? For the record, I am now using a Collgen-2 unit with a fish tank bubbler and it allegedly cuts off at 5ppm. Convenient, but I won't have a warm feeling until I can measure the output. (and probably modify the circuit). Erwin -- The silver-list is a moderated forum for discussion of colloidal silver. To join or quit silver-list or silver-digest send an e-mail message to: silver-list-requ...@eskimo.com -or- silver-digest-requ...@eskimo.com with the word subscribe or unsubscribe in the SUBJECT line. To post, address your message to: silver-list@eskimo.com Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <mdev...@eskimo.com>
