BEE Digital Circuits 4

Question 1

Which of the following is a universal gate because it can implement any Boolean function on its own?

Accepted Answer

NOR

Answer

NOR is a universal gate; using only NOR gates, you can construct NOT, AND, OR, and any other logic function.

Question 2

In an SR latch built from NOR gates, what happens when both S=1 and R=1 are applied simultaneously?

Accepted Answer

Q=0 and Q̄=0 (forbidden state)

Answer

With S=R=1 in a NOR-based SR latch, both outputs are forced to 0, which is the forbidden/invalid state because Q and Q̄ are no longer complementary.

Question 3

A binary ripple counter uses 4 T flip-flops. After 19 clock pulses, what is the counter output (MSB to LSB)?

Accepted Answer

0011

Answer

19 in 4-bit binary is 10011₂; a 4-bit counter truncates to the lower 4 bits: 0011 (19 mod 16 = 3 = 0011₂).

Question 4

What does the term 'fan-out' refer to in digital logic?

Accepted Answer

The maximum number of gate inputs that a gate output can reliably drive

Answer

Fan-out specifies how many standard gate inputs the output of a given gate can drive while maintaining valid logic levels.

Question 5

Which circuit converts a BCD (Binary Coded Decimal) input to a seven-segment display output?

Accepted Answer

Decoder

Answer

A BCD-to-seven-segment decoder takes a 4-bit BCD input and produces the 7 output signals needed to drive the correct segments of a seven-segment display.

BEE - Bachelor of Electrical Engineering Practice Test

BEE - Bachelor of Electrical Engineering Practice Test

BEE Digital Circuits 4