# Top 100 MCQs On Logic Gates with Answers

## Top 100 MCQs On Logic Gates with Answers

Here we share these Logic Gates MCQs and these questions are really help for you, my dear students MCQs On Logic Gates

1. The AND function can be used to and the OR function can be used to .

A. enable, disable

B. disable, enable

C. enable or disable, enable or disable

D. detect, invert

1. One advantage TTL has over CMOS is that TTL is __.

A. less expensive

B. not sensitive to electrostatic discharge

C. faster

D. more widely available

1. A 2-input NOR gate is equivalent to a __.

A. negative-OR gate

B. negative-AND gate

C. negative-NAND gate

D. none of the above

1. If a 3-input OR gate has eight input possibilities, how many of those possibilities will result in a HIGH output?

A. 1

B. 2

C. 7

D. 8

1. Fan-out is specified in terms of __.

A. voltage

B. current

C. wattage

1. The output of an AND gate with three inputs, A, B, and C, is HIGH when __.

A. A = 1, B = 1, C = 0

B. A = 0, B = 0, C = 0

C. A = 1, B = 1, C = 1

D. A = 1, B = 0, C = 1

1. If a 3-input NOR gate has eight input possibilities, how many of those possibilities will result in a HIGH output?

A. 1

B. 2

C. 7

D. 8

1. If a signal passing through a gate is inhibited by sending a LOW into one of the inputs, and the output is HIGH, the gate is a(n):

A. AND

B. NAND

C. NOR

D. OR

1. A device used to display one or more digital signals so that they can be compared to expected timing diagrams for the signals is a:

A. DMM

B. spectrum analyzer

C. logic analyzer

D. frequency counter

1. When used with an IC, what does the term “QUAD” indicate?

A. 2 circuits

B. 4 circuits

C. 6 circuits

D. 8 circuits

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## Logic Gate Questions and Answers

1. How many input combinations would a truth table have for a six-input AND gate?

A. 32

B. 48

C. 64

D. 128

1. What is the circuit number of the IC that contains four two-input AND gates in standard TTL?

A. 7402

B. 7404

C. 7408

D. 7432

1. The terms “low speed” and “high speed,” applied to logic circuits, refer to the __.

A. rise time

B. fall time

C. propagation delay time

D. clock speed

1. The NOR logic gate is the same as the operation of the __ gate with an inverter connected to the output.

A. OR

B. AND

C. NAND

D. none of the above

1. With regard to an AND gate, which statement is true?

A. An AND gate has two inputs and one output.

B. An AND gate has two or more inputs and two outputs.

C. If one input to a 2-input AND gate is HIGH, the output reflects the other input.

D. A 2-input AND gate has eight input possibilities.

1. The term “hex inverter” refers to:

A. an inverter that has six inputs

B. six inverters in a single package

C. a six-input symbolic logic device

D. an inverter that has a history of failure

1. How many inputs are on the logic gates of a 74HC21 IC?

A. 1

B. 2

C. 3

D. 4

1. The basic logic gate whose output is the complement of the input is the:

A. OR gate

B. AND gate

C. inverter

D. comparator

1. When reading a Boolean expression, what does the word “NOT” indicate?

A. the same as

B. inversion

C. high

D. low

1. The output of an exclusive-NOR gate is HIGH if __.

A. the inputs are equal

B. one input is HIGH, and the other input is LOW

C. the inputs are unequal

D. none of the above

## xor gate, and gate, nand gate, nor gate, xnor gate, xnor, not gate, universal gates MCQs

1. Which of the following gates is described by the expression?

A. OR

B. AND

C. NOR

D. NAND

1. What is the Boolean expression for a four-input OR gate?

A. Y = A + B + C + D

B. Y = A· B · C · D

C. Y = A – B – C – D

D. Y = A \$ B \$ C \$ D

1. How many truth table entries are necessary for a four-input circuit?

A. 4

B. 8

C. 12

D. 16

1. What does the small bubble on the output of the NAND gate logic symbol mean?

A. open collector output

B. tristate

C. The output is inverted.

D. none of the above

1. What are the pin numbers of the outputs of the gates in a 7432 IC?

A. 3, 6, 10, and 13

B. 1, 4, 10, and 13

C. 3, 6, 8, and 11

D. 1, 4, 8, and 11

1. The output of a NOT gate is HIGH when __.

A. the input is LOW

B. the input is HIGH

C. power is applied to the gate’s IC

D. power is removed from the gate’s IC

1. How many inputs of a four-input AND gate must be HIGH in order for the output of the logic gate to go HIGH?

A. any one of the inputs

B. any two of the inputs

C. any three of the inputs

D. all four inputs

1. If the output of a three-input AND gate must be a logic LOW, what must the condition of the inputs be?

A. All inputs must be LOW.

B. All inputs must be HIGH.

C. At least one input must be LOW.

D. At least one input must be HIGH.

1. Logically, the output of a NOR gate would have the same Boolean expression as a(n):

A. NAND gate immediately followed by an inverter

B. OR gate immediately followed by an inverter

C. AND gate immediately followed by an inverter

D. NOR gate immediately followed by an inverter

1. 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?

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

B. The output of the gate appears to be open.

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

D. The gate is a tristate device.

## Logic Gate Questions and Answers with PDF

1. What is the Boolean expression for a three-input AND gate?

A. X = A + B + C

B. X = A · B · C

C. A – B – C

D. A \$ B \$ C

1. How many entries would a truth table for a four-input NAND gate have?

A. 2

B. 8

C. 16

D. 32

1. The Boolean expression for a 3-input OR gate is __.

A. X = A + B

B. X = A + B + C

C. X = ABC

D. X = A + BC

1. From the truth table for a three-input NOR gate, what is the only condition of inputs A, B, and C that will make the output X high?

A. A = 1, B = 1, C = 1

B. A = 1, B = 0, C = 0

C. A = 0, B = 0, C = 1

D. A = 0, B = 0, C = 0

1. The logic gate that will have a LOW output when any one of its inputs is HIGH is the:

A. NAND gate

B. AND gate

C. NOR gate

D. OR gate

1. The output of a NAND gate is LOW if __.

A. all inputs are LOW

B. all inputs are HIGH

C. any input is LOW

D. any input is HIGH

1. Which of the following gates has the exact inverse output of the OR gate for all possible input combinations?

A. NOR

B. NOT

C. NAND

D. AND

1. What is the difference between a 7400 and a 7411 IC

A. 7400 has two four-input NAND gates; 7411 has three three-input AND gates

B. 7400 has four two-input NAND gates; 7411 has three three-input AND gates

C. 7400 has two four-input AND gates; 7411 has three three-input NAND gates

D. 7400 has four two-input AND gates; 7411 has three three-input NAND gates

1. The output of an exclusive-OR gate is HIGH if __.

A. all inputs are LOW

B. all inputs are HIGH

C. the inputs are unequal

D. none of the above

1. A clock signal with a period of 1 s is applied to the input of an enable gate. The output must contain six pulses. How long must the enable pulse be active?

A. Enable must be active for 0 s.

B. Enable must be active for 3 s.

C. Enable must be active for 6 s.

D. Enable must be active for 12 s.

## FAQs On Logic Gates

### What are logic gates?

A logic gate is a device that acts as a building block for digital circuits. They perform basic logical functions that are fundamental to digital circuits. Most electronic devices we use today will have some form of logic gates in them.

### What are 7 logic gates?

The basic logic gates are classified into seven types: AND gate, OR gate, XOR gate, NAND gate, NOR gate, XNOR gate, and NOT gate. The truth table is used to show the logic gate function. All the logic gates have two inputs except the NOT gate, which has only one input.

### What is logic gate and its types?

Logic gates are the basic building blocks of any digital system. It is an electronic circuit having one or more than one input and only one output. The relationship between the input and the output is based on a certain logic. Based on this, logic gates are named as AND gate, OR gate, NOT gate etc.