# Logic Gates MCQs

## A logic circuit whose output is LOW when at least one input is HIGH is a(n) _________ gate.

• A. NOR
• B. AND
• C. NAND
• D. exclusive-OR gate
• Correct Answer: Option A

## A NAND gate has:

• A. LOW inputs and a LOW output
• B. HIGH inputs and a HIGH output
• C. LOW inputs and a HIGH output
• D. None of the these
• Correct Answer: Option C

## A single transistor can be used to build which of the following digital logic gates?

• A. AND gates
• B. OR gates
• C. NOT gates
• D. NAND gates
• Correct Answer: Option C

## Exclusive-OR (XOR) logic gates can be constructed from what other logic gates?

• A. OR gates only
• B. AND gates and NOT gates
• C. AND gates, OR gates, and NOT gates
• D. OR gates and NOT gates
• Correct Answer: Option C

## How many NAND circuits are contained in a 7400 NAND IC?

• A. 1
• B. 2
• C. 4
• D. 8
• Correct Answer: Option C

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

• A. 4
• B. 8
• C. 12
• D. 16
• Correct Answer: Option D

## 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
• Correct Answer: Option B

## If we use an AND gate to inhibit a signal from passing, one of the inputs must be _________.

• A. LOW
• B. HIGH
• C. inverted
• D. floating
• Correct Answer: Option A

## The AND function can be used to ___________ and the OR function can be used to _____________.

• A. enable, disable
• B. disable, enable
• C. synchronize, energize
• D. detect, invert
• Correct Answer: Option A

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

• A. OR gate
• B. AND gate
• C. INVERTER gate
• D. comparator
• Correct Answer: Option C

## The logic gate that will have HIGH or “1” at its output when any one of its inputs is HIGH is a(n):

• A. OR gate
• B. AND gate
• C. NOR gate
• D. NOT gate
• Correct Answer: Option A

## The output will be a LOW for any case when one or more inputs are zero in a(n):

• A. OR gate
• B. NOT gate
• C. AND gate
• D. NAND gate
• Correct Answer: Option C

## What input values will cause an AND logic gate to produce a HIGH output?

• A. At least one input is HIGH.
• B. At least one input is LOW.
• C. All inputs are HIGH.
• D. All inputs are LOW.
• Correct Answer: Option C