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I am looking for a circuit that allows the user to adjust the delta (= hysteresis window) between thresholds using 1 pot. and offset the thresholds using another.

For example - Using one pot. the user sets the window to 0.4V & using the second pot. the user sets the low threshold to 3.2V which means the high threshold is going to be 3.6V (3.2 + 0.4).

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  • \$\begingroup\$ Pots for threshold , offset or hysteresis? PLs define each range \$\endgroup\$ – Sunnyskyguy EE75 Jun 16 at 5:05
  • \$\begingroup\$ Please put a little more effort into your question next time. Readers shouldn't have to decipher what you're asking, especially for a simple question like this. \$\endgroup\$ – Drew Jun 17 at 0:24
  • \$\begingroup\$ You can easily do the threshold part with a POT. But changing the window would effect multiple resistor values. I think you would need to adjust POT1 and POT2 to set the window, then you could adjust POT2 to tweak the threshold. It may be possible to do what you want, but a solution doesn't immediately come to mind. \$\endgroup\$ – hekete Jun 17 at 5:44
  • \$\begingroup\$ @hekete In the classic comparator with hysteresis circuit the "feedback resistor" interacts with the voltage divider that sets the threshold so that's why I am looking for another circuit. \$\endgroup\$ – user733606 Jun 17 at 6:03
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Here is a simple idea, which is maybe stupid. But basically the idea is to cause the reference input to drop instead of causing the signal input to rise. Then it should be just a matter of controlling two dividers:

schematic

simulate this circuit – Schematic created using CircuitLab

This has some obvious problems. Like there is going to be a switching delay. Which may make it entirely unsuitable for your purpose. I haven't simulated or tested this in any way. But I don't actually know what you want to do other than control the two values.

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  • \$\begingroup\$ can you explain a bit about the circuit please? \$\endgroup\$ – user733606 Jun 17 at 19:08
  • \$\begingroup\$ @user733606 I've made a more simple circuit. I think this might do what you want, but I'm not totally clear on what you actually plan to do with it. \$\endgroup\$ – hekete Jun 18 at 5:37
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There is a design note from TI here that discusses hysteresis and threshold.
Another useful article is here.
You should be able to work out which resistors need to be adjustable.

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