Ex-OR and Ex-NOR Gates MCQs

Question 1

In VHDL, macrofunctions is/are:

Accepted Answer

preprogrammed TTL devices.

Answer

digital circuits.

Answer

analog circuits.

Answer

a set of bit vectors.

Question 2

Which of the following expressions is in the product-of-sums form?

Accepted Answer

(A + B)(C + D)

Answer

(AB)(CD)

Answer

AB(CD)

Answer

AB + CD

Question 3

Which of the following is an important feature of the sum-of-products form of expressions?

Accepted Answer

All logic circuits are reduced to nothing more than simple AND and OR operations.

Answer

The delay times are greatly reduced over other forms.

Answer

No signal must pass through more than two gates, not including inverters.

Answer

The maximum number of gates that any signal must pass through is reduced by a factor of two.

Question 4

An output gate is connected to four input gates; the circuit does not function. Preliminary tests with the DMM indicate that the power is applied; scope tests show that the primary input gate has a pulsing signal, while the interconnecting node has no signal. The four load gates are all on different ICs. Which instrument will best help isolate the problem?

Accepted Answer

Current tracer

Answer

Logic probe

Answer

Oscilloscope

Answer

Logic analyzer

Question 5

The binary numbers A = 1100 and B = 1001 are applied to the inputs of a comparator. What are the output levels?

Accepted Answer

A > B = 1, A < B = 0, A = B = 0

Answer

A > B = 1, A < B = 0, A < B = 1

Answer

A > B = 0, A < B = 1, A = B = 0

Answer

A > B = 0, A < B = 1, A = B = 1

Question 6

A logic probe is placed on the output of a gate and the display indicator is dim. A pulser is used on each of the input terminals, but the output indication does not change. What is wrong?

Accepted Answer

The output of the gate appears to be open.

Answer

The dim indication on the logic probe indicates that the supply voltage is probably low.

Answer

The dim indication is a result of a bad ground connection on the logic probe.

Answer

The gate may be a tristate device.

Question 7

Two 4-bit binary numbers (1011 and 1111) are applied to a 4-bit parallel adder. The carry input is 1. What are the values for the sum and carry output?

Accepted Answer

4321 = 1011, Cout = 1

Answer

4321 = 0111, Cout = 0

Answer

4321 = 1111, Cout = 1

Answer

4321 = 1100, Cout = 1

Question 8

Each "1" entry in a K-map square represents:

Accepted Answer

a HIGH for each input truth table condition that produces a HIGH output.

Answer

a HIGH output on the truth table for all LOW input combinations.

Answer

a LOW output for all possible HIGH input conditions.

Answer

a DON'T CARE condition for all possible input truth table combinations.

Question 9

Looping on a K-map always results in the elimination of:

Accepted Answer

variables within the loop that appear in both complemented and uncomplemented form.

Answer

variables within the loop that appear only in their complemented form.

Answer

variables that remain unchanged within the loop.

Answer

variables within the loop that appear only in their uncomplemented form.