Digital Design MCQs

Question 1

The ________ circuit overcomes the problem of switching caused by jitter on the inputs.

Accepted Answer

Schmitt trigger

Answer

astable multivibrator

Answer

monostable multivibrator

Answer

bistable multivibrator

Question 2

Why would a delay gate be needed for a digital circuit?

Accepted Answer

to provide for setup times and hold times

Answer

A delay gate is never needed.

Answer

to provide for setup times

Answer

to provide for hold times

Question 3

A Schmitt trigger has VT+ = 2.0 V and VT– = 1.2 V. What is the hysteresis voltage of the Schmitt trigger?

Accepted Answer

0.8 volt

Answer

0.4 volt

Answer

0.6 volt

Answer

1.2 volts

Question 4

Which of the following circuit parameters would be most likely to limit the maximum operating frequency of a flip-flop?

Accepted Answer

propagation delay time

Answer

setup and hold time

Answer

clock pulse HIGH and LOW time

Answer

clock transition time

Question 5

A 0.01-F capacitor is recommended by TTL manufacturers for ________ the power supply.

Accepted Answer

decoupling

Answer

filtering

Answer

rectifying

Answer

grounding

Question 6

Why is the Schmitt trigger needed in the 60-Hz TTL-level clock pulse generator?

Accepted Answer

to provide a sharp pulse waveform

Answer

to provide a triangle wave

Answer

to provide a sine wave

Answer

to provide a rounded pulse waveform

Question 7

The main concern when using a pull-down resistor is:

Accepted Answer

the high power dissipation of the resistor

Answer

the low power dissipation of the resistor

Answer

it will keep a floating terminal LOW

Answer

it will cause false triggering

Question 8

Look up the propagation delay from the clock to the output for the 7476. Are the HIGH-to-LOW and LOW-to-HIGH propagation delays the same?

Accepted Answer

no, tPLH = 25 ns, tPHL = 40 ns

Answer

yes

Answer

no, tPLH = 40 ns, tPHL = 25 ns

Answer

no, tPHL = 25 ns, tPLH = 40 ns

Question 9

What would be the output voltage of a 7814 voltage regulator?

Accepted Answer

+14 V dc

Answer

–14 V dc

Answer

–8 V dc

Answer

+8 V dc