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Comparators and Schmitt Triggers — MCQs – EE

1. A comparator is a circuit that:

(A) Amplifies the difference between two signals


(B) Compares two input voltages and produces a digital output


(C) Integrates the input signal


(D) Differentiates the input signal



2. The output of a comparator is usually:

(A) Analog


(B) Digital


(C) AC


(D) Triangular



3. A comparator operates mostly in the:

(A) Linear region


(B) Saturation region


(C) Active region


(D) Cut-off region



4. In an inverting comparator, the reference voltage is applied to the:

(A) Inverting input


(B) Non-inverting input


(C) Output terminal


(D) Ground terminal



5. In a non-inverting comparator, the reference voltage is applied to the:

(A) Inverting input


(B) Non-inverting input


(C) Output terminal


(D) Power terminal



6. The output of an ideal comparator is:

(A) Infinite


(B) Constant


(C) Either high or low


(D) Linear with input



7. The threshold voltage of a comparator is the voltage:

(A) At which output switches


(B) Always equal to zero


(C) Of the Op-Amp power supply


(D) That controls bias current



8. A comparator can be used to convert:

(A) Digital to analog signal


(B) Analog to digital signal


(C) DC to AC signal


(D) AC to DC signal



9. A comparator circuit with hysteresis is called a:

(A) Integrator


(B) Differentiator


(C) Schmitt Trigger


(D) Amplifier



10. Hysteresis in a Schmitt Trigger helps to:

(A) Reduce noise and false triggering


(B) Increase gain


(C) Decrease speed


(D) Increase offset voltage



11. A Schmitt Trigger is a type of:

(A) Differential amplifier


(B) Comparator with positive feedback


(C) Integrator with capacitor


(D) Low-pass filter



12. The two threshold voltages in a Schmitt Trigger are known as:

(A) High and low bias voltages


(B) Upper and lower trigger points


(C) Positive and negative peaks


(D) Supply limits



13. The region between upper and lower trigger voltages is called:

(A) Hysteresis band


(B) Gain region


(C) Feedback loop


(D) Dead zone



14. In a Schmitt Trigger, the output changes state only when:

(A) Input crosses a threshold voltage


(B) Input is zero


(C) Output reaches maximum


(D) Feedback is removed



15. A Schmitt Trigger converts a noisy analog input into a:

(A) Ramp output


(B) Smooth DC signal


(C) Clean digital pulse


(D) Sine wave



16. The feedback used in a Schmitt Trigger is:

(A) Negative feedback


(B) Positive feedback


(C) No feedback


(D) Capacitive feedback



17. The main application of a comparator is in:

(A) Signal amplification


(B) Signal comparison and threshold detection


(C) Current regulation


(D) Filtering



18. The main application of a Schmitt Trigger is in:

(A) DC amplification


(B) Wave shaping and noise elimination


(C) Power control


(D) Frequency modulation



19. The output of a Schmitt Trigger for a sinusoidal input is:

(A) Sine wave


(B) Square wave


(C) Ramp wave


(D) Triangular wave



20. In a comparator circuit, the speed of operation is limited by:

(A) Slew rate of the Op-Amp


(B) Feedback resistance


(C) Input offset voltage


(D) Power supply



21. A comparator is also known as a:

(A) Level detector


(B) Current amplifier


(C) Voltage follower


(D) Buffer amplifier



22. The output of a comparator saturates at approximately:

(A) Reference voltage


(B) ± supply voltage


(C) Ground potential


(D) Zero volts



23. A Schmitt Trigger can be used as a:

(A) Memory element


(B) Multivibrator


(C) Pulse generator


(D) All of the above



24. In a non-inverting Schmitt Trigger, the input is applied to:

(A) Inverting input terminal


(B) Non-inverting input terminal


(C) Output terminal


(D) Feedback network



25. The hysteresis width of a Schmitt Trigger depends on:

(A) Supply voltage and resistor ratio


(B) Input offset voltage


(C) Bias current


(D) Input capacitance



26. A zero-crossing detector is a type of:

(A) Integrator


(B) Differentiator


(C) Comparator


(D) Amplifier



27. The zero-crossing detector changes its output when:

(A) Input crosses zero volts


(B) Input reaches peak value


(C) Input equals output


(D) Input saturates



28. The output of a comparator without hysteresis can:

(A) Oscillate due to noise near threshold


(B) Remain stable at all times


(C) Never switch


(D) Always stay high



29. In a Schmitt Trigger, positive feedback causes:

(A) Hysteresis


(B) Stability


(C) Negative gain


(D) Phase shift



30. A Schmitt Trigger is preferred over a simple comparator when:

(A) Input is noisy or slowly varying


(B) Input is pure DC


(C) Input has no fluctuations


(D) Input is at high frequency only



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