LM393 hysteresis

Discussion in 'General Electronics Chat' started by Audrey Win, Jan 20, 2014.

  1. Audrey Win

    Thread Starter New Member

    Sep 12, 2013
    3
    0
    I know this post is kinda long time ago. but i cant help but curious. why do you have to use both comparators. Can't it work with one comparator only? won't it work if U1a output connect to R4 directly?
    I will appreciate the explanation since I am new to circuit design and trying to learn. Thanks a lot.

    PS: I refer to the post "Thermal control with hysteresis" . I couldn't reply the thread since it was posted long time ago. So I create new thread.
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,003
    3,232
    Yes, you could use just one comparator. The top comparator is used to provide hysteresis of the trip point but that could be provided by a small amount of positive feedback around just the bottom comparator. Both comparators were used because they were both in one package so it was free to use.
     
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