andemand80 Posted November 24, 2009 Report Share Posted November 24, 2009 I need help to which resistors that i should change to make the hysteresis Smaller in my schmitt trigger(Se picture). i use this as a temperature controller in my garage but now the hysteresis is equivalent about eight degrees celcius, which is Too much, i was hoping to get it to around half a degree... Best hopes from here:) Quote Link to comment Share on other sites More sharing options...
Hero999 Posted November 25, 2009 Report Share Posted November 25, 2009 I don't like that circuit myself, I prefer using a PNP and NPN transistor because the output voltage swing is greater.Look at the circuit where's the positive feedback?Try changing some of the component values.Why not use an IC comparator such as the LM311?http://www.silicontronics.com/index.php?action=ezportal;sa=page;p=17 Quote Link to comment Share on other sites More sharing options...
desolatordan Posted November 25, 2009 Report Share Posted November 25, 2009 http://www.play-hookey.com/digital/experiments/rtl_schmitt.htmlRaise RC2? Lower R2? Quote Link to comment Share on other sites More sharing options...
andemand80 Posted November 26, 2009 Author Report Share Posted November 26, 2009 Thanks a lot- desolatordan- for the link:)Apparently i can control the hysteresis by raising the resistance of RE- wupti! And it worked!!!Yei! :) Quote Link to comment Share on other sites More sharing options...
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