hallooooo all.please help with acircuit for teperature regulature using thermistor.temperature range 37+or _ 5degrees.currently ihave one with temperature range -20 to+50

 

Why do you need the additional circuit? You state the one you have is good to +50, which is well beyond the 37 deg. you say you want to regulate.

 

Beenthere,
I believe the O.P. wants a circuit that will maintain the temperature of the thermistor to within 5°C of 37°C; the circuit version he has now simply reads the temperature over the -20°C to +50°C.

That is, if I'm interpreting his request properly - but we need verification from the original poster if that interpretation is correct.

If that is in fact what they want, here's a link to a circuit that should do the trick:
http://www.solorb.com/elect/constemp/index.html