What is the function of the Hall effect in semiconductors?
A Measure voltage
B Measure magnetic field
C Measure current
D Measure temperature
The Hall effect occurs when a magnetic field is applied perpendicular to the current in a semiconductor. It generates a transverse voltage (Hall voltage), which can be measured to determine the magnetic field strength, important in sensors and measurements.
What happens when a diode is reverse biased beyond its breakdown voltage?
A It breaks down and conducts heavily
B It conducts current
C It stops conducting
D It amplifies the signal
When a diode is reverse biased beyond its breakdown voltage, it enters reverse breakdown, where the depletion region collapses, and a large current starts flowing in reverse. This characteristic is used in Zener diodes for voltage regulation.
In a Bipolar Junction Transistor (BJT), what is the role of the base region?
A Emit charge carriers
B Collect charge carriers
C Amplify signals
D Control current
The base region 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 between the collector and emitter, enabling signal amplification.
Which of the following is true for an N channel MOSFET?
A Current flows from drain to source
B Current flows from source to drain
C Electrons are the majority carriers
D Holes are the majority carriers
In an N channel MOSFET, electrons are the majority carriers. These electrons move from the source to the drain when the gate voltage is applied, controlling the current flow through the device.
What is the main feature of CMOS technology?
A Low power consumption
B High power consumption
C High signal gain
D Fast switching
CMOS (Complementary Metal Oxide Semiconductor) technology is known for its low power consumption. It uses both n type and p type MOSFETs, consuming power only during switching, making it ideal for modern digital circuits and microprocessors.
What is the effect of temperature on the conductivity of intrinsic semiconductors?
A Decreases conductivity
B Increases conductivity
C No effect
D It becomes insulating
As temperature increases, more electrons gain sufficient energy to jump from the valence band to the conduction band, thus increasing the number of charge carriers and the overall conductivity of the intrinsic semiconductor.
What is the primary characteristic of a photodiode?
A Detects light
B Amplifies signals
C Rectifies current
D Emits light
A photodiode detects light and converts it into an electrical signal. It operates in reverse bias and generates a current when illuminated by light, making it essential in optical sensing, communication, and other optoelectronic applications.
What does doping a semiconductor with Group III elements (like boron) create?
A N type semiconductor
B Intrinsic semiconductor
C Conductor
D P type semiconductor
Doping a semiconductor with Group III elements like boron introduces “holes” (the absence of electrons) as majority charge carriers. This creates a p type semiconductor, which is used for forming p n junctions in devices like diodes and transistors.
In a solar cell, what is the role of the p n junction?
A Absorb photons
B Generate light
C Create an electric field
D Collect charge carriers
The p n junction in a solar cell creates an electric field that separates the electron hole pairs generated by photon absorption. This electric field drives the electrons and holes toward the electrodes, generating current and powering devices.
What is the main function of a Zener diode?
A Current amplification
B Voltage regulation
C Light detection
D Signal modulation
A Zener diode is used for voltage regulation. When reverse biased, it maintains a constant voltage once the reverse voltage exceeds its Zener breakdown voltage, making it useful for stabilizing voltages in power supply circuits.
What is the primary feature of a direct bandgap semiconductor?
A Efficient light emission
B Poor light emission
C High resistivity
D Low electron mobility
Direct bandgap semiconductors, such as Gallium Arsenide (GaAs), efficiently emit light when an electron transitions from the conduction band to the valence band. This property is critical in devices like LEDs and semiconductor lasers.
In the Hall effect, what causes the development of a transverse voltage?
A Current
B Voltage
C Magnetic field
D Temperature
The Hall effect occurs when a current carrying conductor is exposed to a magnetic field. The magnetic field exerts a force on the charge carriers, causing them to accumulate on one side of the conductor, generating a transverse voltage.
What is the role of an emitter resistor in a common emitter amplifier?
A Increase gain
B Decrease gain
C Provide feedback
D Stabilize biasing
The emitter resistor in a common emitter amplifier stabilizes the biasing of the transistor by providing negative feedback. This ensures the operating point remains stable, improving the amplifier’s performance across temperature variations.
What is the effect of increasing the collector emitter voltage in a BJT?
A Increases current
B Increases gain
C No effect
D Reaches saturation
Increasing the collector emitter voltage in the active region of a BJT does not significantly affect the current, as the transistor operates in a constant current mode. However, beyond saturation, the voltage increase will not increase current.
In an N channel MOSFET, what happens when the gate source voltage exceeds the threshold voltage?
A The channel conducts current
B The transistor turns off
C The transistor enters saturation
D The source current increases
When the gate source voltage exceeds the threshold voltage in an N channel MOSFET, it creates a conductive channel between the source and drain, allowing current to flow. This enables the MOSFET to act as a switch or amplifier.