The output of Schmitt trigger is:

Question

Question

This question was previously asked in

RRB ALP Electronics Mechanic 21 Jan 2019 Official Paper (Shift 3)

Answer 1

Schmitt trigger

Schmitt Trigger is a Bi-stable Multivibrator and its output remains in either of the two stable states i.e. +V_sat or -V_sat

The circuit gives +V_sat when the non-inverting input is greater than the inverting input.

The circuit gives -Vsat when the inverting input is greater than the non-inverting input.

As the output oscillates between the two states, the Schmitt trigger always generates a square wave.

Working of Schmitt trigger

F4 S.B Madhu 13.03.20 D 6

When V_ref > V_in, the output is +V_CC

When V_ref < V_in, the output is -V_EE

The reference voltage is either V_UT or V_LT.

Upper threshold voltage \((V_{UT})=+V_{CC}({R_2\over R_1+R_2})\)

Lower threshold voltage \((V_{LT})=-V_{EE}({R_2\over R_1+R_2})\)

F4 S.B Madhu 13.03.20 D 7