BEE Digital Circuits 5

Question 1

What is the purpose of a schmitt trigger in digital circuits?

Accepted Answer

To provide hysteresis for clean switching on noisy or slow-transition inputs

Answer

A Schmitt trigger uses two different threshold voltages (hysteresis) to produce a clean, bounce-free digital output from noisy or slowly changing input signals.

Question 2

In which number system is the addition 1011 + 1101 performed, and what is the result?

Accepted Answer

Binary; result is 11000

Answer

1011₂ (11) + 1101₂ (13) = 11000₂ (24) in binary arithmetic.

Question 3

Which type of ROM can be erased by exposing it to ultraviolet light?

Accepted Answer

EPROM

Answer

EPROM (Erasable Programmable ROM) is erased by UV light shone through its quartz window, resetting all cells to 1.

Question 4

A synchronous 3-bit up counter is currently in state 110. What is the next state?

Accepted Answer

111

Answer

110₂ = 6; the next count is 7 = 111₂ in a standard 3-bit synchronous up counter.

Question 5

Which logic expression represents the output of an XNOR gate for inputs A and B?

Accepted Answer

A·B + Ā·B̄

Answer

XNOR outputs 1 when both inputs are the same: A·B (both 1) or Ā·B̄ (both 0), which is the complement of XOR.

BEE - Bachelor of Electrical Engineering Practice Test

BEE - Bachelor of Electrical Engineering Practice Test

BEE Digital Circuits 5