Comparator with SCHMIIT trigger oscillations

QSPICE
1

Hi everyone,

I need to use a comparator and, as explained by @KSKelvin (Confusion on understanding the Schmitt Inverter device - #3 by carlvanwormer), I’m using the HMITT function with the standard configuration; I don’t use VT and VH.
If I don’t introduce hysteresis, everything is fine, but if I use hysteresis, I get oscillations and I don’t understand where they come from.
Is there someone who can help me?

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Thanks for your help.

2

Hysteresis comparator is positive feedback!

3

Oops, yes of course :joy:, thanks a lot.