ELC201 Chapter1-3

Which of the following is NOT a common semiconductor material mentioned? (a) Ge (Germanium) (b) Si (Silicon) (c) GaAs (Gallium Arsenide) (d) Au (Gold)

d) Au (Gold)

What is the typical behavior of intrinsic semiconductor conductivity with increasing temperature? (a) It increases, exhibiting a negative temperature coefficient. (b) It decreases, exhibiting a positive temperature coefficient. (c) It remains constant. (d) It becomes zero.

a) It increases, exhibiting a negative temperature coefficient.

In an N-type semiconductor, the majority charge carriers are: (a) Holes (b) Protons (c) Electrons (d) Neutrons

c) Electrons

What happens to the depletion region of a diode under forward bias? (a) It widens. (b) It narrows. (c) It remains unchanged. (d) It disappears completely.

b) It narrows.

An ideal diode has: (a) 0V threshold voltage and ∞Ω reverse resistance. (b) ~0.7V threshold voltage and low reverse resistance. (c) 0V threshold voltage and 0Ω reverse resistance. (d) ~0.7V threshold voltage and ∞Ω reverse resistance.

a) 0V threshold voltage and ∞Ω reverse resistance.

The Zener diode is primarily used for: (a) Amplification (b) Light emission (c) Voltage regulation. (d) Rectification.

c) Voltage regulation.

The color of light emitted by an LED depends on its: (a) Current level (b) Physical size (c) Energy band gap. (d) Reverse breakdown voltage

c) Energy band gap.

When was the first Integrated Circuit (IC) developed by Jack Kilby & Robert Noyce? (a) 1961 (b) 1965 (c) 1958 (d) 1970

c) 1958

At absolute zero (0K), intrinsic semiconductor materials behave like: (a) Perfect conductors (b) Perfect insulators (no charge carriers). (c) Superconductors (d) N-type semiconductors

b) Perfect insulators (no charge carriers).

P-type semiconductor materials are created by doping with: (a) 5-valent atoms (donors) (b) 3-valent atoms (acceptors). (c) Intrinsic atoms (d) 4-valent atoms

b) 3-valent atoms (acceptors).

In a semiconductor diode, how do electron flow and hole flow relate during conduction? (a) They flow in the same direction. (b) They flow in opposite directions. (c) Only electrons flow. (d) Only holes flow.

b) They flow in opposite directions.

The reverse saturation current (Is) in a diode generally: (a) Halves for every 10°C rise in temperature. (b) Doubles for every 10°C rise in temperature. (c) Remains constant with temperature. (d) Decreases linearly with temperature.

b) Doubles for every 10°C rise in temperature.

A practical silicon diode typically starts to conduct significantly when the forward voltage is: (a) Exactly 0V (b) Around 0.3V (c) Around 0.7V. (d) Greater than 5V

c) Around 0.7V.

DC (static) resistance of a diode is calculated as: (a) Change in voltage / Change in current (ΔV/ΔI) (b) Voltage / Current (V/I) at the operating point. (c) The slope of the V-I characteristic at the origin. (d) Always 0 Ω in forward bias.

b) Voltage / Current (V/I) at the operating point.

Semiconductors have electrical conductivity that is: (a) Higher than metals and lower than insulators. (b) Lower than metals and higher than insulators. (c) The same as metals. (d) The same as insulators.

b) Lower than metals and higher than insulators.

The bonds formed by sharing electrons between atoms for stability in semiconductors are called: (a) Ionic bonds (b) Metallic bonds (c) Covalent bonds. (d) Hydrogen bonds

c) Covalent bonds.

In the energy band diagram of a semiconductor, the lower energy band primarily occupied by electrons is the: (a) Conduction band (b) Forbidden energy gap (c) Valence band. (d) Fermi level

c) Valence band.

Doping a pure semiconductor crystal with impurity atoms creates an: (a) Intrinsic material (b) Extrinsic material. (c) Insulating material (d) Superconducting material

b) Extrinsic material.

With no external voltage applied to a p-n junction, what forms at the interface? (a) A conduction channel (b) A depletion region. (c) A short circuit (d) An open circuit

b) A depletion region.

The typical threshold voltage for a practical silicon diode is approximately: (a) 0.3 V (b) 0.7 V. (c) 1.1 V (d) 0 V

b) 0.7 V.

Which of the following is a type of diode equivalent circuit model that includes the threshold voltage and dynamic resistance? (a) Ideal model (b) Simplified model (c) Piecewise-linear model. (d) Complex model

c) Piecewise-linear model.

What is a common maximum reverse voltage rating for many LEDs? (a) 0.7 V (b) 1.5 V (c) 3–5 V. (d) 12 V

c) 3–5 V.

The energy difference between the valence band and the conduction band in a semiconductor is called the: (a) Fermi level (b) Work function (c) Forbidden energy gap (Eg). (d) Binding energy

c) Forbidden energy gap (Eg).

Who are credited with the development of the first Integrated Circuit in 1958? (a) Bardeen, Brattain, and Shockley (b) Jack Kilby & Robert Noyce. (c) Geoffrey Dummer (d) Gordon Moore

b) Jack Kilby & Robert Noyce.

What is the primary goal of load-line analysis? (a) To determine the diode's breakdown voltage. (b) To find the operating point (Q-point) of the diode in a circuit. (c) To measure the AC resistance of the diode. (d) To calculate the PIV of the rectifier.

b) To find the operating point (Q-point) of the diode in a circuit.

A half-wave rectifier typically uses: (a) One diode. (b) Two diodes. (c) Four diodes. (d) A Zener diode.

a) One diode.

Which type of full-wave rectifier does NOT require a center-tapped transformer? (a) Center-tapped rectifier (b) Bridge rectifier. (c) Half-wave rectifier (d) Voltage doubler

b) Bridge rectifier.

For the same DC output voltage, which rectifier configuration generally has a higher PIV requirement for its diodes? (a) Half-wave rectifier (b) Bridge rectifier (c) Center-tapped full-wave rectifier. (d) They all have the same PIV.

c) Center-tapped full-wave rectifier.

When analyzing a circuit with both DC and AC sources using superposition, how are the responses combined? (a) The AC response is ignored. (b) The DC response is ignored. (c) The DC and AC responses are added together (superimposed). (d) The product of DC and AC responses is taken.

c) The DC and AC responses are added together (superimposed).

The load line in diode circuit analysis is a: (a) Curve representing the diode's non-linear characteristics. (b) Straight line determined by the external network resistance and voltage source. (c) Horizontal line representing constant current. (d) Vertical line representing constant voltage.

b) Straight line determined by the external network resistance and voltage source.

A half-wave rectifier converts: (a) The entire AC input into a steady DC output. (b) Only one half-cycle (positive or negative) of the AC input into pulsating DC. (c) AC input into a higher frequency AC output. (d) DC input into AC output.

b) Only one half-cycle (positive or negative) of the AC input into pulsating DC.

A bridge rectifier utilizes: (a) One diode (b) Two diodes (c) Three diodes (d) Four diodes.

d) Four diodes.

PIV is an abbreviation for: (a) Peak Input Voltage (b) Positive Ion Voltage (c) Peak Inverse Voltage. (d) Primary Ideal Voltage

c) Peak Inverse Voltage.

In a circuit with DC and AC sources, the diode's fundamental electrical characteristics (V-I curve): (a) Change depending on whether the DC or AC source is being considered. (b) Remain fixed, while the network determines the operating point. (c) Are only relevant for the DC analysis part. (d) Are only relevant for the AC analysis part.

b) Remain fixed, while the network determines the operating point.

The intersection of the diode characteristic curve and the load line represents the: (a) Breakdown voltage (VBV) (b) Reverse saturation current (Is) (c) Operating point (Q-point: VDQ and IDQ). (d) Threshold voltage (VT)

c) Operating point (Q-point: VDQ and IDQ).

Rectification is the process of converting: (a) DC to AC (b) AC to DC. (c) High frequency AC to low frequency AC (d) Low voltage DC to high voltage DC

b) AC to DC.

Which pair of points can be used to plot the load line for a simple diode circuit with a voltage source E and series resistor R? (a) (0, E/R) and (E, 0). (b) (0, 0) and (E, E/R) (c) (VT, 0) and (E, Imax) (d) (0, Is) and (VBV, 0)

a) (0, E/R) and (E, 0).

In a half-wave rectifier using a practical silicon diode (VT ≈ 0.7V), during the conduction phase, the peak output voltage will be: (a) Equal to the peak input voltage. (b) Approximately 0.7V higher than the peak input voltage. (c) Approximately 0.7V lower than the peak input voltage. (d) Zero.

c) Approximately 0.7V lower than the peak input voltage.

It is crucial to ensure that the PIV rating of a diode in a rectifier circuit is: (a) Lower than the peak input voltage. (b) Equal to the average output voltage. (c) Not exceeded by the actual peak inverse voltage experienced by the diode. (d) As close to zero as possible.

c) Not exceeded by the actual peak inverse voltage experienced by the diode.

Which of the following is NOT a terminal of a BJT? (a) Emitter (E) (b) Base (B) (c) Collector (C) (d) Gate (G).

d) Gate (G).

In which mode of operation are both the emitter-base and collector-base junctions of a BJT reverse-biased? (a) Active mode (b) Saturation mode (c) Cut-off mode. (d) Breakdown mode

c) Cut-off mode.

For a BJT to operate as an amplifier (in the active region), how must its junctions be biased? (a) Emitter-Base: Forward-biased, Collector-Base: Forward-biased (b) Emitter-Base: Reverse-biased, Collector-Base: Reverse-biased (c) Emitter-Base: Forward-biased, Collector-Base: Reverse-biased. (d) Emitter-Base: Reverse-biased, Collector-Base: Forward-biased

c) Emitter-Base: Forward-biased, Collector-Base: Reverse-biased.

Which BJT configuration is known for having a low input impedance, high output impedance, and a current gain (α) that is typically less than 1? (a) Common-Emitter (CE) (b) Common-Collector (CC) (c) Common-Base (CB). (d) Common-Drain (CD)

c) Common-Base (CB).

The current gain β (beta) in a Common-Emitter (CE) configuration is defined as the ratio of: (a) Base current (IB) to Collector current (IC) (b) Collector current (IC) to Emitter current (IE) (c) Emitter current (IE) to Base current (IB) (d) Collector current (IC) to Base current (IB).

d) Collector current (IC) to Base current (IB).

Which BJT configuration is often referred to as an emitter follower and is used as a buffer due to its high input impedance and low output impedance? (a) Common-Emitter (CE) (b) Common-Collector (CC). (c) Common-Base (CB) (d) Common-Gate (CG)

b) Common-Collector (CC).

An NPN transistor consists of: (a) A P-type layer sandwiched between two N-type layers. (b) An N-type layer sandwiched between two P-type layers. (c) Two N-type layers only. (d) Two P-type layers only.

a) A P-type layer sandwiched between two N-type layers.

In saturation mode, a BJT behaves most like a: (a) Open switch (b) Closed switch. (c) Current source (d) Voltage source

b) Closed switch.

Which equation correctly relates the currents in a BJT? (a) IB = IC + IE (b) IC = IB + IE (c) IE = IB + IC. (d) IE = IC - IB

c) IE = IB + IC.

The Common-Emitter (CE) configuration is widely used because it typically provides: (a) Only voltage gain. (b) Only current gain. (c) Both voltage and current gain. (d) Neither voltage nor current gain, only buffering.

c) Both voltage and current gain.

Exceeding the maximum rated power dissipation of a BJT can lead to: (a) Increased efficiency (b) Improved linearity (c) Device overheating and potential failure. (d) Operation in the cut-off region.

c) Device overheating and potential failure.

The two main types of Bipolar Junction Transistors are: (a) JFET and MOSFET (b) N-channel and P-channel (c) NPN and PNP. (d) Diode and Triode

c) NPN and PNP.

In the active mode of an NPN transistor, the collector current is primarily composed of: (a) Holes flowing from emitter to collector. (b) Electrons injected from the emitter and collected by the collector. (c) Holes flowing from base to collector. (d) Electrons flowing from base to collector.

b) Electrons injected from the emitter and collected by the collector.

The Common-Collector (CC) configuration is also widely known as an: (a) Emitter Resistor (b) Emitter Follower. (c) Base Follower (d) Collector Follower

b) Emitter Follower.

When testing a BJT junction with an ohmmeter, a forward-biased junction (e.g., base-emitter of an NPN with positive on base, negative on emitter) should ideally show: (a) Very high resistance (near infinite). (b) Low resistance. (c) The same resistance as a reverse-biased junction. (d) Zero resistance.

b) Low resistance.

Which of the following is typically found on a transistor specification sheet? (a) The circuit diagram it will be used in. (b) The color of the transistor casing. (c) Maximum collector current (ICmax) and current gain (β or hFE). (d) The name of the circuit designer who prefers this transistor.

c) Maximum collector current (ICmax) and current gain (β or hFE).