You did not wire up the voltage source correctly. The negative terminal of the voltage source should be connected to ground, not to OUT.

Here is the circuit with the +5V node replaced by a voltage source V2, and closer to the layout of your circuits.

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![schematic](https://i.sstatic.net/oTFQqViA.png)

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With the parameters for SW1 set at V_T = 2.5 and V_H = 1.5, the output looks like this:

[![enter image description here][1]][1]

In the edited version of the question, there is a circuit similar to this, but with the parameters for the switch set at Vt = 2.5 and Vh = -0.75.  Try changing Vh to 1.5 as in the original circuit.


  [1]: https://i.sstatic.net/fzusQdF6.png