Are You Into Digital Electronics?
Digital Electronics is an electronics which is based on 0's and 1's for the representation of the information. This area includes digital terms such as gates, flip flops, timing signals, multiplexer etc. If you are into such area then surely you may not face troubles facing this quiz. All the best!
Questions and Answers
- 1.
Which number system has base 16?
- A.
Decimal.
- B.
Octal.
- C.
Hexadecimal.
- D.
Binary.
Correct Answer
C. Hexadecimal.Explanation
The number system that has a base of 16 is hexadecimal. In this system, numbers are represented using 16 different symbols, including the digits 0-9 and the letters A-F. Hexadecimal is commonly used in computer programming and digital systems because it can represent large numbers with fewer digits compared to decimal or binary.Rate this question:
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- 2.
How many entries will be in the truth table of a 3 input NAND gate?
- A.
3
- B.
6
- C.
9
- D.
8
Correct Answer
D. 8Explanation
A 3-input NAND gate has 3 input variables, each of which can be either 0 or 1. For each combination of inputs, the NAND gate will produce a single output. Since there are 2 possible values for each input variable, there will be a total of 2^3 = 8 different combinations of inputs. Therefore, there will be 8 entries in the truth table of a 3-input NAND gate.Rate this question:
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- 3.
In a SR latch built from NOR gates, which condition is not allowed?
- A.
S=1, R=0
- B.
S=1, R=1
- C.
S=0, R=1
- D.
S=0, R=0
Correct Answer
B. S=1, R=1Explanation
The condition S=1, R=1 is not allowed in a SR latch built from NOR gates. This is because when both S and R inputs are set to 1, it creates a feedback loop where the output of the latch becomes unpredictable. This condition is known as the "invalid" or "forbidden" state in a SR latch, as it violates the basic functionality of the latch.Rate this question:
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- 4.
Which of these sets are designated as universal gates?
- A.
EX-OR.
- B.
NAND NOR.
- C.
EX-NOR.
- D.
All of above.
Correct Answer
B. NAND NOR.Explanation
NAND and NOR gates are designated as universal gates because they can be used to implement any logic function. This means that any other logic gate can be built using only NAND or only NOR gates. This property makes NAND and NOR gates extremely versatile and widely used in digital circuit design. The other options, EX-OR and EX-NOR, are not considered universal gates as they cannot be used to implement all logic functions on their own.Rate this question:
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- 5.
In the toggle mode, JK flip flop has:
- A.
J = 0, K = 0
- B.
J = 1, K = 1
- C.
J = 0, K = 1
- D.
J = 1, K = 0
Correct Answer
B. J = 1, K = 1 -
- 6.
A digital circuit that can store one bit is called:
- A.
X-OR gate.
- B.
Logic gate.
- C.
Flip flop.
- D.
Register.
Correct Answer
C. Flip flop.Explanation
A flip flop is a digital circuit that can store one bit of information. It has two stable states, usually represented as 0 and 1, and can hold its current state until it is changed by an external input signal. This makes it suitable for storing and remembering data in digital systems. An X-OR gate is a logic gate that outputs true only when the number of true inputs is odd. While logic gates are fundamental building blocks of digital circuits, they cannot store information. A register is a collection of flip flops used for storing multiple bits of data. Therefore, the correct answer is flip flop.Rate this question:
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- 7.
Full adder has:
- A.
2 inputs and 1 output.
- B.
3 inputs and 2 outputs.
- C.
2 inputs and 2 outputs.
- D.
2 inputs and 3 outputs.
Correct Answer
B. 3 inputs and 2 outputs.Explanation
A full adder is a digital circuit that performs addition of three binary digits and produces a sum and a carry out. The two inputs represent the two numbers to be added, while the third input represents the carry in from the previous stage. The two outputs are the sum of the three inputs and the carry out to the next stage. Therefore, a full adder has 3 inputs and 2 outputs.Rate this question:
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- 8.
A PN junction allows current flow when:
- A.
The n-type material is more positive than the p-type material.
- B.
The p-type material is more positive than the n-type material.
- C.
Both the n-type and p-type materials have the same potential.
- D.
There is no potential on the n-type or p-type materials.
Correct Answer
B. The p-type material is more positive than the n-type material.Explanation
In a PN junction, the p-type material is doped with acceptor impurities, creating a surplus of positively charged holes. The n-type material, on the other hand, is doped with donor impurities, resulting in an excess of negatively charged electrons. When the p-side of the junction is more positive than the n-side, the positive holes are attracted to the negative electrons, creating a depletion region where no current flows. However, when the p-side is more positive, it repels the positive holes, allowing them to diffuse into the n-side and combine with the negative electrons, resulting in current flow. Therefore, the correct answer is that the p-type material is more positive than the n-type material.Rate this question:
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- 9.
When a diode is forward biased, the voltage across it:
- A.
Is directly proportional to the current.
- B.
Is inversely proportional to the current.
- C.
Is inversely proportional to the power.
- D.
Is directly proportional to the power.
Correct Answer
A. Is directly proportional to the current.Explanation
When a diode is forward biased, the voltage across it is directly proportional to the current. This means that as the current flowing through the diode increases, the voltage across it also increases. This relationship is due to the behavior of the diode, which allows current to flow more easily in the forward direction. As more current flows, the voltage drop across the diode increases in a linear manner. Therefore, the voltage across a forward biased diode can be directly determined by the current flowing through it.Rate this question:
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- 10.
Diode is:
- A.
2-terminal device
- B.
3-terminal
- C.
4-terminal
- D.
None of the options
Correct Answer
A. 2-terminal deviceExplanation
A diode is a 2-terminal device because it has two electrodes, namely the anode and the cathode. It allows current to flow in only one direction, from the anode to the cathode, while blocking current flow in the opposite direction. The two terminals are essential for the diode's functionality and its ability to regulate the flow of electrical current.Rate this question:
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- 11.
The forward voltage drop across a silicon diode is:
- A.
2.5V
- B.
3V
- C.
10V
- D.
0.7V
Correct Answer
D. 0.7VExplanation
The forward voltage drop across a silicon diode is typically around 0.7V. This is because silicon diodes have a forward voltage drop of approximately 0.7V when conducting current in the forward direction. This characteristic is important to consider when designing circuits involving diodes, as it affects the voltage levels and current flow within the circuit.Rate this question:
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- 12.
What is the state of an ideal diode in the region of non conduction?
- A.
A short circuit.
- B.
An open circuit.
- C.
Unpredictable.
- D.
Undefined.
Correct Answer
B. An open circuit.Explanation
In the region of non conduction, an ideal diode behaves like an open circuit. This means that there is no current flowing through the diode and the voltage across the diode is equal to the applied voltage. In an open circuit, there is a break in the circuit, preventing the flow of current. Therefore, an open circuit is the correct state for an ideal diode in the non conduction region.Rate this question:
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- 13.
A simple flip flop is:
- A.
Is 2 bit memory.
- B.
Is a four state device.
- C.
Is 1 bit memory.
- D.
Has nothing to do with memory.
Correct Answer
C. Is 1 bit memory.Explanation
A simple flip flop is a basic digital circuit that can store one bit of information. It has two stable states, which can represent a binary value of either 0 or 1. Therefore, it can be considered as a 1 bit memory.Rate this question:
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- 14.
How many binary bits are necessary to represent 32 different numbers?
- A.
2
- B.
3
- C.
4
- D.
5
Correct Answer
D. 5Explanation
To represent 32 different numbers, we need to find the smallest power of 2 that is greater than or equal to 32. In this case, 2^5 = 32, so we need 5 binary bits to represent 32 different numbers.Rate this question:
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- 15.
In the decimal numbering system, what is MSD?
- A.
The middle digit of a stream of numbers
- B.
The last digit on the right
- C.
The digit to the right of the decimal point
- D.
The digit with the most weight
Correct Answer
D. The digit with the most weightExplanation
The Most Significant Digit (MSD) refers to the digit with the most weight in a number. In the decimal numbering system, the leftmost digit has the highest weight, and it determines the overall value of the number. Therefore, the correct answer is "The digit with the most weight."Rate this question:
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- 16.
Which of the following doping will produce a P-type semiconductor?
- A.
Germanium with phosphorus.
- B.
Silicon with Germanium.
- C.
Silicon with Indium.
- D.
Germanium with Antimony.
Correct Answer
C. Silicon with Indium.Explanation
Silicon with Indium will produce a P-type semiconductor because Indium is a Group III element with three valence electrons. When it is added to silicon, which is a Group IV element with four valence electrons, the extra electron from Indium creates a "hole" in the crystal lattice. These holes act as positive charge carriers, resulting in a P-type semiconductor.Rate this question:
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- 17.
The depletion region in a junction diode contains:
- A.
Only charge carriers (of minority type and majority type).
- B.
No charge at all.
- C.
Vacuum, and no atoms at all.
- D.
Only ions i.e. Immobile charges.
Correct Answer
D. Only ions i.e. Immobile charges.Explanation
The depletion region in a junction diode contains only ions, which are immobile charges. This region is formed when a p-type and an n-type semiconductor are brought together, creating a junction. As a result of this junction, the majority carriers from each side diffuse across the junction and recombine with the majority carriers of the opposite type, leaving behind immobile ions. This creates a region depleted of charge carriers, hence the name "depletion region."Rate this question:
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- 18.
The depletion layer of a PN junction diode has:
- A.
Only free mobile holes.
- B.
Only free mobile electrons.
- C.
Neither free mobile electrons nor holes.
- D.
Both free mobile holes as well as electrons.
Correct Answer
C. Neither free mobile electrons nor holes.Explanation
The depletion layer of a PN junction diode is formed due to the diffusion of electrons from the N-region to the P-region and holes from the P-region to the N-region. This diffusion process creates a region near the junction that is depleted of both free mobile electrons and holes. Therefore, the correct answer is that the depletion layer has neither free mobile electrons nor holes.Rate this question:
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- 19.
An AND gate with schematic "bubbles" on its inputs performs the same function as:
- A.
NOT
- B.
NAND
- C.
OR
- D.
NOR
Correct Answer
D. NORExplanation
An AND gate with "bubbles" on its inputs performs the same function as a NOR gate. The "bubbles" indicate that the inputs are inverted or negated. In an AND gate, all inputs must be high or true in order for the output to be high or true. However, with the presence of the "bubbles", the inputs are inverted, meaning that if any of the inputs are high or true, the output of the gate will be low or false. This behavior is the same as that of a NOR gate, where the output is only high or true when all inputs are low or false.Rate this question:
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- 20.
Suppose Y is a Boolean variable, which of the following expressions willbe equal to 1?
- A.
Y XOR Y
- B.
Y AND 0
- C.
Y NOR 1
- D.
Y XNOR Y
Correct Answer
D. Y XNOR YExplanation
The expression Y XNOR Y will be equal to 1 when Y is equal to 1. XNOR is the logical operator that returns true (1) if both operands are equal, and false (0) otherwise. In this case, since Y is a Boolean variable, it can only have a value of either 0 or 1. So when Y is equal to 1, both operands in the expression Y XNOR Y will be equal, resulting in the expression being equal to 1.Rate this question:
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- 21.
An OR gate can be imagined as:
- A.
Switches connected in series.
- B.
Switches connected in parallel.
- C.
MOS transistors connected in series.
- D.
All of the above.
Correct Answer
B. Switches connected in parallel.Explanation
An OR gate can be imagined as switches connected in parallel because in an OR gate, the output is true if any of the inputs are true. This is similar to switches connected in parallel, where the circuit is closed if any of the switches are closed. In contrast, switches connected in series would require all switches to be closed for the circuit to be closed, which is not the behavior of an OR gate. MOS transistors connected in series may be used in other types of logic gates, but not specifically in an OR gate.Rate this question:
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- 22.
If both inputs of an S-R NAND latch are LOW, what will happen to the output?
- A.
The output will reset.
- B.
The output would become unpredictable.
- C.
No change would occur at the output.
- D.
The output will toggle.
Correct Answer
C. No change would occur at the output.Explanation
When both inputs of an S-R NAND latch are LOW, the latch will remain in its current state, and there will be no change in the output. This is because a LOW input to a NAND gate results in a HIGH output, and since both inputs are LOW, the output will remain HIGH. Therefore, the output will not reset, become unpredictable, or toggle.Rate this question:
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- 23.
An AND gate can be imagined as:
- A.
Switches connected in series.
- B.
Switches connected in parallel.
- C.
MOS transistors connected in series.
- D.
All of the above.
Correct Answer
A. Switches connected in series.Explanation
An AND gate can be imagined as switches connected in series because in an AND gate, both inputs must be true (or switches closed) in order for the output to be true (or switch closed). Just like switches connected in series, where all switches must be closed for the circuit to be complete and the current to flow.Rate this question:
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- 24.
NOR gate is equivalent to a bubbled input:
- A.
AND
- B.
NAND
- C.
XOR
- D.
OR
Correct Answer
A. ANDExplanation
A NOR gate is equivalent to a bubbled input AND gate because a NOR gate outputs a high signal only when both of its inputs are low. In other words, it performs the opposite operation of an AND gate. By adding a bubble (inversion) to one of the inputs of an AND gate, we can achieve the same logic as a NOR gate.Rate this question:
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- 25.
Zener diode operates in:
- A.
Saturation region.
- B.
Forward region.
- C.
Reverse region.
- D.
All of above.
Correct Answer
C. Reverse region.Explanation
A Zener diode operates in the reverse region because it is designed to have a specific breakdown voltage. When the voltage across the diode exceeds this breakdown voltage, it allows current to flow in the reverse direction. This reverse current remains nearly constant even if the voltage changes, making the Zener diode useful for voltage regulation and protection against voltage spikes. In the forward region, the Zener diode behaves like a regular diode, allowing current to flow only in the forward direction when the voltage exceeds the forward voltage drop. The saturation region is not applicable to Zener diodes.Rate this question:
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- 26.
A high reverse voltage applied to the diode will cause an affect known as:
- A.
Avalanche breakdown.
- B.
Punch through.
- C.
Diffussion.
- D.
Saturation.
Correct Answer
A. Avalanche breakdown.Explanation
When a high reverse voltage is applied to a diode, it can cause a phenomenon called avalanche breakdown. This occurs when the electric field across the diode becomes so strong that it frees up enough charge carriers to create a chain reaction, leading to a rapid increase in current flow. This can cause the diode to breakdown and potentially be damaged. Punch through refers to a different phenomenon where the electric field is strong enough to penetrate the thin depletion region of a diode. Diffusion and saturation are not related to the effects of high reverse voltage on a diode.Rate this question:
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- 27.
NAND Gate is a combination of:
- A.
AND and OR
- B.
NAND and NOR
- C.
OR and NOT
- D.
AND and NOT
Correct Answer
D. AND and NOTExplanation
A NAND gate is a combination of an AND gate and a NOT gate. The AND gate takes two inputs and produces an output only when both inputs are high. The NOT gate takes a single input and produces the opposite output. By combining these two gates, a NAND gate produces an output that is the opposite of the AND gate's output. Therefore, the correct answer is AND and NOT.Rate this question:
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- 28.
Logic gate will have ----- Inputs.
- A.
1 or more inputs.
- B.
1 input.
- C.
2 inputs.
- D.
2 or more inputs.
Correct Answer
A. 1 or more inputs.Explanation
A logic gate is a fundamental building block of digital circuits that performs a specific logical operation. It takes one or more inputs and produces a single output based on the given logical function. Therefore, the correct answer is "1 or more inputs" because a logic gate can have a single input or multiple inputs depending on the specific circuit design and the logical operation it is intended to perform.Rate this question:
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- 29.
What kind of device is diode:
- A.
Bipolar.
- B.
Unipolar.
- C.
Linear.
- D.
Bilateral.
Correct Answer
A. Bipolar.Explanation
A diode is classified as a bipolar device because it consists of two layers of semiconductor material, typically a P-type and an N-type, which are joined together. This construction allows the diode to conduct current in both directions. In other words, it can function as a switch that allows current to flow in one direction while blocking it in the opposite direction. This characteristic makes the diode useful in various electronic circuits, such as rectifiers and voltage regulators.Rate this question:
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- 30.
How is non conducting diode biased?
- A.
Forward.
- B.
Reverse.
- C.
Poorly.
- D.
None of these.
Correct Answer
B. Reverse.Explanation
A non-conducting diode is biased in reverse. In this biasing, the positive terminal of the battery is connected to the cathode of the diode, and the negative terminal is connected to the anode. This reverse biasing creates a depletion region at the junction of the diode, which prevents the flow of current through the diode. Therefore, the correct answer is reverse.Rate this question:
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- 31.
If two inputs are shorted in NAND or NOR gate the output will be
- A.
OR gate.
- B.
NOT gate.
- C.
AND gate.
- D.
None of the above.
Correct Answer
B. NOT gate.Explanation
When two inputs are shorted in a NAND or NOR gate, it means that both inputs are connected together. In a NAND gate, the output is normally high, but when both inputs are shorted, the output becomes low. This behavior is similar to a NOT gate, where the output is the opposite of the input. Therefore, the correct answer is NOT gate.Rate this question:
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- 32.
Ripple factor of full wave Rectifier is:
- A.
1.21
- B.
0.483
- C.
0.5
- D.
None of these
Correct Answer
B. 0.483Explanation
The ripple factor of a full wave rectifier is a measure of the amount of AC ripple voltage present in the rectified output. It is defined as the ratio of the RMS value of the ripple voltage to the DC output voltage. The correct answer of 0.483 suggests that the ripple factor of a full wave rectifier is approximately 0.483, indicating that there is a moderate amount of AC ripple voltage present in the rectified output.Rate this question:
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- 33.
Junction diode can be used as:
- A.
Amplifier.
- B.
Voltage regulator.
- C.
Rectifier.
- D.
Limiter.
Correct Answer
C. Rectifier.Explanation
A junction diode can be used as a rectifier because it allows current to flow in only one direction. When the diode is forward-biased, it conducts current and allows it to flow through, resulting in a rectified output. However, when the diode is reverse-biased, it blocks the current flow, acting as an open circuit. This property of the junction diode makes it suitable for converting alternating current (AC) to direct current (DC) by rectifying the waveform.Rate this question:
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- 34.
Maximum rectifier efficiency of full wave rectifier is:
- A.
81.2%
- B.
40.6%
- C.
100%
- D.
92%
Correct Answer
A. 81.2%Explanation
The maximum rectifier efficiency of a full wave rectifier is 81.2%. This means that the rectifier is able to convert 81.2% of the input AC power into DC power. The efficiency of a rectifier is determined by the amount of power loss during the conversion process. A higher efficiency indicates less power loss and a more efficient conversion. In this case, the full wave rectifier has a maximum efficiency of 81.2%, meaning it is able to convert a significant portion of the input power into usable DC power.Rate this question:
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- 35.
Gate which gives the output High when both the inputs are equal:
- A.
NOR
- B.
EX-NOR
- C.
EX-OR
- D.
OR
Correct Answer
B. EX-NORExplanation
The gate that gives the output High when both the inputs are equal is the EX-NOR gate. This gate is a combination of the XOR gate and the NOT gate. It produces a High output only when both inputs are the same, either both 0 or both 1. If the inputs are different, the output will be Low. Therefore, the EX-NOR gate is the correct answer for this question.Rate this question:
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- 36.
Output is high when both the inputs are different:
- A.
OR
- B.
EX-OR
- C.
EX-NOR
- D.
NOR
Correct Answer
B. EX-ORExplanation
The EX-OR gate produces a high output when both of its inputs are different. In other words, if one input is high and the other is low, the output will be high. If both inputs are the same (either both high or both low), the output will be low. Therefore, the EX-OR gate is the correct answer for this question as it satisfies the condition mentioned in the statement.Rate this question:
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- 37.
The forward voltage drop across germanium PN junction diode is:
- A.
0.3V
- B.
0.7V
- C.
0.37V
- D.
0.73V
Correct Answer
A. 0.3VExplanation
The forward voltage drop across a germanium PN junction diode is 0.3V. This is because germanium diodes have a lower forward voltage drop compared to silicon diodes, which typically have a forward voltage drop of around 0.7V. The forward voltage drop is the amount of voltage required to overcome the barrier potential of the diode and allow current to flow through it.Rate this question:
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- 38.
Zener diode has:
- A.
Two PN junctions.
- B.
Three PN junctions.
- C.
One PN junctions.
- D.
None of the above.
Correct Answer
C. One PN junctions.Explanation
A Zener diode is a type of diode that is designed to operate in the reverse breakdown region. It has only one PN junction, which allows current to flow in the reverse direction when a certain voltage, known as the Zener voltage, is reached. This characteristic makes Zener diodes useful for voltage regulation and protection against voltage spikes.Rate this question:
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- 39.
Zener diode is used as:
- A.
Amplifier.
- B.
Rectifier.
- C.
Voltage regulator.
- D.
Limiter.
Correct Answer
C. Voltage regulator.Explanation
A Zener diode is specifically designed to operate in the reverse breakdown region, where it exhibits a controlled voltage drop. This characteristic makes it ideal for regulating voltage in electronic circuits. By connecting a Zener diode in parallel with a load, it can maintain a constant voltage across the load, even when there are variations in the input voltage. This makes it useful in applications where a stable voltage supply is required, such as in power supplies, voltage references, and voltage stabilizers.Rate this question:
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- 40.
In the breakdown region Zener behaves as a:
- A.
Constant current source.
- B.
Constant voltage source.
- C.
Constant resistance source.
- D.
None of above.
Correct Answer
B. Constant voltage source.Explanation
In the breakdown region, a Zener diode behaves as a constant voltage source. This means that it maintains a relatively constant voltage across its terminals, regardless of changes in the current flowing through it. This characteristic makes Zener diodes useful for voltage regulation and protection in electronic circuits.Rate this question:
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Nov 16, 2023Quiz Edited by
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Oct 26, 2018Quiz Created by
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