Junaid Posted May 1, 2005 Report Share Posted May 1, 2005 Hello Buddies!I've made a project which get data from temprature sensor from LM35 (ratings 10mV with the increment of 1 degress celcius) having voltage output then convert this analog data in digital by using ADC0804 then by using microcontroller 89C51 i phussed it to the serial port.Now i wana get temprature from PT100 which is a temprature controlled resistor (rating 100 Ohms at 0 Degree Celcius and 0.3846 Ohms/degree). i've made a voltage divider circuit and place a constant current source, now what is happing in calculation and in practice lets suppose the voltage at 34 degree Celcius is 1.1254 and the voltage is at 36 degree ceicius is 1.1258 this means the step voltage is of 4 mili Amps now tell me how can i increase this 4 milli upto 20 mili or 10 mili, so i can sense it through ADC, if any one have any knowledge about it then please help me!thank You!Junaid Quote Link to comment Share on other sites More sharing options...
MP Posted May 3, 2005 Report Share Posted May 3, 2005 First, you will need a precision resistor with a tolerance of .01% or you will have drift all over the place. Then run the resistor from the excitation voltage to the input of the AD converter. Then connect the temp sensor between the input of the AD and common. Then you will calculate the resistance to give you the correct voltage scale. This is determined by the voltage you use and the value of the resistor. Use your chart that came with the temp sensor to calculate the voltage divider.MP Quote Link to comment Share on other sites More sharing options...
Junaid Posted May 4, 2005 Author Report Share Posted May 4, 2005 I want to know the Schematic please help me! Quote Link to comment Share on other sites More sharing options...
Junaid Posted May 4, 2005 Author Report Share Posted May 4, 2005 Please Help me as Soon as possible........... Quote Link to comment Share on other sites More sharing options...
hotwaterwizard Posted May 5, 2005 Report Share Posted May 5, 2005 http://www.samson.de/pdf_en/t52030en.pdf Quote Link to comment Share on other sites More sharing options...
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