What is the main characteristic of a p-type semiconductor?
A High conductivity
B Excess electrons
C Excess holes
D Low conductivity
A p-type semiconductor has an abundance of “holes” (missing electrons), which act as positive charge carriers. These holes are the majority carriers in p-type materials, enabling current flow in semiconductor devices.
What is the purpose of a diode in a circuit?
A Signal switching
B Amplification
C Signal modulation
D Current rectification
A diode allows current to flow in one direction only, acting as a rectifier in circuits. This property is essential in converting alternating current (AC) to direct current (DC) in power supplies.
What is the primary function of a transistor?
A Signal amplification
B Data storage
C Voltage regulation
D Current rectification
A transistor is mainly used for signal amplification. It can take a weak input signal and increase its power, making it suitable for audio, radio, and other electronic communication devices.
Which material has a wider band gap?
A Germanium
B Silicon
C Gallium Arsenide
D Copper
Gallium Arsenide (GaAs) has a wider band gap than silicon, which makes it ideal for high-speed devices, high-frequency applications, and optoelectronics like laser diodes and LEDs.
In which region of a transistor is the current gain the highest?
A Saturation region
B Active region
C Breakdown region
D Cutoff region
In the active region of a transistor, the device operates as an amplifier. The current gain is highest here, allowing the transistor to effectively amplify weak input signals for output.
What is the characteristic property of an n-type semiconductor?
A Excess electrons
B High resistance
C Excess holes
D No free carriers
N-type semiconductors are doped with donor impurities that provide extra electrons as charge carriers. These free electrons are the majority carriers, enabling efficient conduction in n-type materials.
What happens to the conductivity of a semiconductor when temperature increases?
A Fluctuates
B Remains the same
C Increases
D Increases
As temperature increases, more electrons gain enough energy to jump into the conduction band, increasing the conductivity of the semiconductor. This behavior is typical of semiconductors as opposed to metals.
What is the purpose of the base region in a BJT (Bipolar Junction Transistor)?
A Amplify signal
B Control current
C Provide power
D Emit electrons
The base region of a BJT controls the flow of current between the collector and emitter. A small current at the base controls a much larger current, enabling the transistor to amplify signals.
Which of the following is a key application of a photodiode?
A Signal amplification
B Current rectification
C Light detection
D Light emission
A photodiode is used to detect light. It operates in reverse bias, generating a current when illuminated by light, which is essential in optical communication systems and light sensors.
What is the main property of a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor)?
A Voltage-controlled current
B Data storage
C Current rectification
D Signal amplification
The MOSFET controls current flow based on the voltage applied to its gate. It is widely used for switching and amplification in digital and analog circuits, with no direct current required at the gate.
What happens when a p-n junction is reverse biased?
A It increases current
B It conducts current
C It neutralizes current
D It blocks current
In reverse bias, the p-type side is connected to the negative terminal, and the n-type side is connected to the positive terminal. This increases the barrier potential and prevents current flow through the diode.
What is the primary function of a solar cell?
A Energy storage
B Voltage regulation
C Light-to-electricity conversion
D Signal amplification
A solar cell converts sunlight into electrical energy through the photovoltaic effect. When light strikes the semiconductor material, it generates electron-hole pairs, which are then collected to produce electric current.
What is the main feature of a Hall effect sensor?
A Signal modulation
B Magnetic field sensing
C Current amplification
D Light detection
The Hall effect sensor detects the presence and strength of a magnetic field. It generates a voltage perpendicular to the current flow in the presence of a magnetic field, making it useful for position and speed sensing.
What is the main advantage of CMOS technology?
A Low power consumption
B High voltage tolerance
C High speed
D Easy fabrication
CMOS (Complementary Metal-Oxide-Semiconductor) technology uses both n-type and p-type transistors, consuming very little power when idle. This feature makes it ideal for energy-efficient devices like microprocessors and memory chips.
What determines the current-voltage (I-V) characteristics of a diode?
A Band gap
B Capacitance
C Doping level
D Resistance
The I-V characteristics of a diode are largely determined by its doping level. The amount and type of doping control the barrier potential, which in turn affects how the diode conducts current when forward or reverse biased.