What is the charge carrier in an n-type semiconductor?
A Neutrons
B Holes
C Protons
D Electrons
In n-type semiconductors, the majority charge carriers are electrons. These are provided by donor impurities during the doping process, and they contribute to electrical conductivity by moving under an applied electric field.
What does the term ‘band gap’ refer to in semiconductors?
A Voltage level
B Energy difference
C Current flow
D Resistance
The band gap is the energy difference between the conduction band and the valence band in a semiconductor. Electrons must overcome this gap to move from the valence band to the conduction band, allowing electrical conduction.
Which of the following is a key feature of a diode?
A Rectification
B Switching
C Modulation
D Amplification
A diode allows current to flow in one direction only, performing the critical function of rectification. This makes it useful in converting alternating current (AC) into direct current (DC), commonly used in power supplies.
What is the function of a BJT’s collector?
A Amplify signal
B Control current
C Collect charge carriers
D Emit electrons
The collector in a Bipolar Junction Transistor (BJT) is responsible for collecting charge carriers (electrons or holes) that flow through the base and emitter. It plays a critical role in the transistor’s amplification function.
What is the effect of increasing the temperature on a semiconductor?
A Increases resistance
B Decreases resistance
C Increases voltage
D Decreases voltage
As temperature increases, the thermal energy allows more electrons to move from the valence band to the conduction band, increasing the number of free charge carriers and thus decreasing the resistance of the semiconductor.
In which region does a transistor act as a switch?
A Saturation region
B Active region
C Cutoff region
D Breakdown region
In the cutoff region, the transistor behaves like an open switch, with no current flowing from collector to emitter. This is when the base-emitter junction is not forward biased, and the transistor is in its “off” state.
What is the primary purpose of a Zener diode?
A Voltage regulation
B Current rectification
C Light emission
D Signal amplification
A Zener diode is primarily used for voltage regulation. It maintains a constant output voltage by allowing reverse current flow once the voltage exceeds a specific value known as the Zener breakdown voltage.
Which material is most commonly used in the fabrication of integrated circuits (ICs)?
A Aluminum
B Gallium Arsenide
C Silicon
D Copper
Silicon is the most commonly used material for fabricating integrated circuits (ICs) because it has excellent semiconductor properties, is abundant, and is cost-effective. It forms the foundation for most modern electronic devices.
What is the role of the base in a Bipolar Junction Transistor (BJT)?
A Amplify current
B Control current
C Collect current
D Emit current
The base of a BJT controls the current flowing between the collector and emitter. A small current at the base allows a much larger current to flow from the collector to the emitter, enabling the transistor to amplify signals.
What happens when a p-n junction is forward biased?
A It allows current
B It creates a short circuit
C It blocks current
D It increases resistance
In forward bias, the p-type side of the diode is connected to the positive terminal and the n-type side to the negative terminal. This reduces the potential barrier, allowing current to flow through the diode.
What does a MOSFET control?
A Power
B Voltage
C Current
D Signal
A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) primarily controls the flow of current between the source and drain terminals. It acts as a voltage-controlled current device, making it useful for switching and amplification in electronic circuits.
What is the main cause of current in a semiconductor?
A Holes
B Free electrons
C External voltage
D Electromagnetic fields
Current in a semiconductor is primarily caused by the movement of charge carriers (electrons and holes) when an external voltage is applied. This voltage creates an electric field that drives the charge carriers through the material.
What is the effect of high doping concentration in semiconductors?
A Low voltage
B High resistance
C High conductivity
D Low conductivity
High doping concentrations in semiconductors increase the number of free charge carriers, which enhances conductivity. This is essential in creating semiconductor devices like diodes, transistors, and solar cells that require controlled conduction.
What is the function of a Schottky diode?
A Light emission
B Voltage regulation
C Signal amplification
D Rectification
A Schottky diode is a type of diode known for its low forward voltage drop and fast switching capabilities. It is commonly used in high-frequency applications and serves as a rectifier in power supplies.
Which of the following describes the behavior of a diode in reverse bias?
A Blocks current
B Generates light
C Amplifies current
D Conducts current
In reverse bias, the diode blocks current from flowing through it by widening the depletion region. Only a small leakage current may flow, but the diode essentially prevents significant current from passing.