Basic on/off circuit with hysteresis

Discussion in 'The Projects Forum' started by theasus, Jan 5, 2011.

  1. theasus

    Thread Starter New Member

    Sep 12, 2009
    16
    0
    Could you give an example for a basic on/off circuit with hysteresis?I searched the internet but I couldn't find what I exactly want.
    I guess there are two opamps in this circuit;first one is a comparator to campare the other value which is obtained from feedbak sensor(thermocouple or something like that.)and the second one is a circuit with opamp for determining hysteresis interval.But I'm not sure and I need an example circuit and its calculation for this operation.Could you offer something?
    Thanks.
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,103
    3,038
    Take a look at the datasheet for a comparator IC such as LM393. Example circuits will show how to add hysteresis to either an inverting or noninverting comparison. Briefly, the degree of hysteresis is controlled by how much feedback from the comparator's output is brought back around to mix with the input. Lots of feedback means the input signal will have a bigger fight to overcome that feedback and switch the state of the comparator.
     
  3. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
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