avionic Posted February 9, 2006 Report Share Posted February 9, 2006 Hi,my first post here,Im just looking for a bit of help with a project,im building a thermocouple using the AD595 IC powered from a 9V battery,i have a problem with 2 things,1 is the circuit must have a timer built in so it will automatically shut off after about 10 mins,i tried the 4060 IC but no result,can anyone help with this?? The second problem is looking for a single rail op amp which is to amplify the output of the AD595 to the display im using (OEM22),Would the AD8565 or LM324 be suitable??Thanks Quote Link to comment Share on other sites More sharing options...
ante Posted February 9, 2006 Report Share Posted February 9, 2006 Hi avionic,Welcome to our forum,Please post your schematic so we can see what you are up to! ;) Quote Link to comment Share on other sites More sharing options...
avionic Posted February 9, 2006 Author Report Share Posted February 9, 2006 hi thanks for the reply,well the thing is all i have set up is the ad595 in single supply config,i have to design the rest but i have some of the data sheets for the AD595,http://www.google.ie/search?hl=en&q=ad595&meta= Pin 9 will be fed to the op amp i am looking for.but i need to find the correct op amp. Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 9, 2006 Report Share Posted February 9, 2006 Hi Avionic,The AD595 already has an opamp for its output so why add another?Just connect its pins 8 and 9 for an output that is 10mV/degree C. The load should be a high resistance to prevent the IC from heating. Quote Link to comment Share on other sites More sharing options...
ante Posted February 9, 2006 Report Share Posted February 9, 2006 Yeah, that seems like the sensible thing to do! Quote Link to comment Share on other sites More sharing options...
avionic Posted February 10, 2006 Author Report Share Posted February 10, 2006 yea thanks ive that done.now the probelm is driving the display,im using the OEM22 3.5 LCD or maybe the OEM24L(http://documents.rs-components.com/rs-bin/RightSite.dll/getcontent/data.pdf?DMW_FORMAT=pdf&DMW_OBJECTID=0900766b80657512&DMW_DOCBASE=techlib).Both work on full scale deflection from 0 to 200mV,so above 20 degrees on the thermocouple im just going to get a 1 on the lcd screen???how can i fix this? Quote Link to comment Share on other sites More sharing options...
audioguru Posted February 10, 2006 Report Share Posted February 10, 2006 When the AD595 circuit gives more than 200mV when it measures more than 20 degrees C then just use a simple two-resistors voltage divider at the input of the meter for it to read higher voltages. Quote Link to comment Share on other sites More sharing options...
MP Posted February 10, 2006 Report Share Posted February 10, 2006 There should be jumpers on your display which allow for higher voltages. Check your data sheet.MP Quote Link to comment Share on other sites More sharing options...
avionic Posted February 10, 2006 Author Report Share Posted February 10, 2006 oh excellent,thats great thanks,its being ordered at the moment so il be going through the data sheet,thanks for the help. Quote Link to comment Share on other sites More sharing options...
MP Posted February 11, 2006 Report Share Posted February 11, 2006 avionic,Don't be discouraged if you find it does not have the jumpers. Most do.If yours does not have the jumpers, please note that the jumpers are just connections to on-board resistors for a voltage divider. In the case of no jumpers, it is a simple matter of using a voltage divider as audioguru suggested. Either way, you achieve the same goal.MP Quote Link to comment Share on other sites More sharing options...
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