A bistable multi-vibrator that functions as a voltage comparator with hysteresis is called

​A bistable multi-vibrator that functions as a voltage comparator with hysteresis is called ​Schmitt trigger

Explanation:

The circuit diagram of a Schmitt Triger is as shown:

Upper Threshold is given by:

\({V_{UT}} = \frac{{{V_{sat}} \cdot {R_1}}}{{{R_1} + {R_2}}}\)

The Lower threshold is given by:

\({V_{LT}} = \frac{{ - {V_{sat}} \cdot {R_1}}}{{{R_1} + {R_2}}}\)

The transfer characteristic will be:

VH = VUT - VLT → width of the Hysteresis loop.

From the above characteristic, we observe that Schmitt Trigger circuit’s triggering takes place at VUT and VLT

Therefore, as long as, noise amplitude (peak to peak) is in between VLT and VUT the triggering of the circuit does not takes place and our circuit is immune to noise.