Steve_hi Posted March 24, 2007 Report Share Posted March 24, 2007 Looking for schematic and parts list to make pH meter capable of measuring 0 to 14 ph preferably with a 12 vdc power supply Thank you Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 24, 2007 Report Share Posted March 24, 2007 Hi Steve,Look in Google for pH Meter Circuit. There are plenty. Quote Link to comment Share on other sites More sharing options...
Steve_hi Posted March 24, 2007 Author Report Share Posted March 24, 2007 I have one but there are some parts that when i try to order them from futurlec they dont seem to have them there are all kinds of resistors that dont have the same values and a diode too Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 24, 2007 Report Share Posted March 24, 2007 Digikey and Newark would have the parts.1) The opamps are Cmos from National Semiconductor.2) The "diode" is actually a 2.5V voltage reference IC that is much better than a zener diode.3) The resistors have 1% values. Quote Link to comment Share on other sites More sharing options...
Steve_hi Posted March 24, 2007 Author Report Share Posted March 24, 2007 I checked digi key for part LM4040D1Z-2.5but they have no listing for it is there some thing that could be substituted for itAlso the resistors that are listef for sale do not match those asked for by the schematic what does one do for this situation choose the closest one to it or is there a different solution. Thank you Quote Link to comment Share on other sites More sharing options...
Steve_hi Posted March 24, 2007 Author Report Share Posted March 24, 2007 also it is asking for 100k resistor + 3500 ppm Note 12style 144 I dont know what this means Quote Link to comment Share on other sites More sharing options...
audioguru Posted March 24, 2007 Report Share Posted March 24, 2007 Digikey has thousands of LM4040 2.5V reference ICs in stock. In different packages and from different manufacturers. Enter LM4040 in a search then enter 2.5V.Didn't you see the entire pH meter project on the datasheet for the LMC6001 IC? It tells you all about pH and why R1 is a temperature compensating resistor. I don't know where to get R1.The datasheet also tells you how to setup and calibrate the circuit. Quote Link to comment Share on other sites More sharing options...
Steve_hi Posted May 27, 2007 Author Report Share Posted May 27, 2007 A suggestion for new projects to whoever is responsible for this department!!A pH-METERThanks Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 27, 2007 Report Share Posted May 27, 2007 Hi Steve,Anybody can post a project.Why don't you? Quote Link to comment Share on other sites More sharing options...
Steve_hi Posted May 27, 2007 Author Report Share Posted May 27, 2007 I didn't know I could! I will try to figure out how, get it ready and do it.Thanks :) Quote Link to comment Share on other sites More sharing options...
audioguru Posted May 27, 2007 Report Share Posted May 27, 2007 Design a circuit or steal it from another site or from a datasheet.Make a clear schematic, parts list and description about its parts and how the circuits works.Then see "Publish Your Circuit" instructions on the Home page. Quote Link to comment Share on other sites More sharing options...
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