ASTM NCATT Digital Electronics Assessment
Newest (2025 - 2026 Update) From Real Past
Papers Questions – A Set Of 100 Most
Common Exam Frequently Tested Questions
And Answers In Details 100% Verified Exam
Highly Recommendable For Grade A+
1. What numbering system uses only the digits 0 and 1?
A. Decimal
B. Octal
C. Binary
D. Hexadecimal
Answer: Binary
Explanation: Binary is the fundamental numbering system used by all digital
electronic circuits because it consists of only two logic states: 0 and 1.
2. In digital electronics, a logic HIGH is generally represented by:
A. Zero volts
B. Negative voltage
C. Ground
D. A higher voltage level
Answer: A higher voltage level
Explanation: Logic HIGH is represented by a voltage above the defined threshold
for the logic family.
, 3. Which logic gate produces a HIGH output only when all inputs are HIGH?
A. OR
B. XOR
C. NAND
D. AND
Answer: AND
Explanation: An AND gate requires every input to be HIGH before the output
becomes HIGH.
4. What is the output of an OR gate when both inputs are LOW?
A. HIGH
B. Undefined
C. Floating
D. LOW
Answer: LOW
Explanation: An OR gate outputs HIGH if at least one input is HIGH. With both
LOW, the output is LOW.
5. A NOT gate is also known as a:
A. Buffer
B. Comparator
C. Decoder
D. Inverter
Answer: Inverter
Explanation: A NOT gate inverts the input logic state.
6. Which gate outputs the opposite of an AND gate?
,A. NOR
B. XOR
C. OR
D. NAND
Answer: NAND
Explanation: A NAND gate is an AND gate followed by inversion.
7. Which gate outputs the opposite of an OR gate?
A. XOR
B. XNOR
C. Buffer
D. NOR
Answer: NOR
Explanation: A NOR gate is an OR gate followed by a NOT gate.
8. Which gate produces HIGH only when the inputs are different?
A. AND
B. OR
C. NAND
D. XOR
Answer: XOR
Explanation: XOR detects inequality between two inputs.
9. Which gate produces HIGH when both inputs are identical?
A. XOR
B. NAND
, C. NOR
D. XNOR
Answer: XNOR
Explanation: XNOR outputs HIGH whenever the inputs match.
10.Which logic family generally operates at 5 volts?
A. ECL
B. CMOS 4000 only
C. RTL
D. TTL
Answer: TTL
Explanation: Standard TTL logic commonly operates from a 5-volt supply.
11.CMOS technology is primarily known for:
A. High current consumption
B. High heat generation
C. Analog operation only
D. Low power consumption
Answer: Low power consumption
Explanation: CMOS circuits consume very little power except during switching.
12.Which numbering system uses the digits 0 through 9?
A. Binary
B. Hexadecimal
C. Octal
D. Decimal
Newest (2025 - 2026 Update) From Real Past
Papers Questions – A Set Of 100 Most
Common Exam Frequently Tested Questions
And Answers In Details 100% Verified Exam
Highly Recommendable For Grade A+
1. What numbering system uses only the digits 0 and 1?
A. Decimal
B. Octal
C. Binary
D. Hexadecimal
Answer: Binary
Explanation: Binary is the fundamental numbering system used by all digital
electronic circuits because it consists of only two logic states: 0 and 1.
2. In digital electronics, a logic HIGH is generally represented by:
A. Zero volts
B. Negative voltage
C. Ground
D. A higher voltage level
Answer: A higher voltage level
Explanation: Logic HIGH is represented by a voltage above the defined threshold
for the logic family.
, 3. Which logic gate produces a HIGH output only when all inputs are HIGH?
A. OR
B. XOR
C. NAND
D. AND
Answer: AND
Explanation: An AND gate requires every input to be HIGH before the output
becomes HIGH.
4. What is the output of an OR gate when both inputs are LOW?
A. HIGH
B. Undefined
C. Floating
D. LOW
Answer: LOW
Explanation: An OR gate outputs HIGH if at least one input is HIGH. With both
LOW, the output is LOW.
5. A NOT gate is also known as a:
A. Buffer
B. Comparator
C. Decoder
D. Inverter
Answer: Inverter
Explanation: A NOT gate inverts the input logic state.
6. Which gate outputs the opposite of an AND gate?
,A. NOR
B. XOR
C. OR
D. NAND
Answer: NAND
Explanation: A NAND gate is an AND gate followed by inversion.
7. Which gate outputs the opposite of an OR gate?
A. XOR
B. XNOR
C. Buffer
D. NOR
Answer: NOR
Explanation: A NOR gate is an OR gate followed by a NOT gate.
8. Which gate produces HIGH only when the inputs are different?
A. AND
B. OR
C. NAND
D. XOR
Answer: XOR
Explanation: XOR detects inequality between two inputs.
9. Which gate produces HIGH when both inputs are identical?
A. XOR
B. NAND
, C. NOR
D. XNOR
Answer: XNOR
Explanation: XNOR outputs HIGH whenever the inputs match.
10.Which logic family generally operates at 5 volts?
A. ECL
B. CMOS 4000 only
C. RTL
D. TTL
Answer: TTL
Explanation: Standard TTL logic commonly operates from a 5-volt supply.
11.CMOS technology is primarily known for:
A. High current consumption
B. High heat generation
C. Analog operation only
D. Low power consumption
Answer: Low power consumption
Explanation: CMOS circuits consume very little power except during switching.
12.Which numbering system uses the digits 0 through 9?
A. Binary
B. Hexadecimal
C. Octal
D. Decimal
