E6 - CIRCUIT COMPONENTS [6 Exam Questions - 6 Groups] 70 Questions Flashcards
“In what application is gallium arsenide used as a semiconductor material?”
A. In high-current rectifier circuits
B. In high-power audio circuits
C. In microwave circuits
D. In very low-frequency RF circuits
C. In microwave circuits
“Which of the following semiconductor materials contains excess free electrons?”
A. N-type
B. P-type
C. Bipolar
D. Insulated gate
A. N-type
“Why does a PN-junction diode not conduct current when reverse biased?”
A. Only P-type semiconductor material can conduct current
B. Only N-type semiconductor material can conduct current
C. Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
D. Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator
C. Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region
“What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?”
A. Insulator impurity
B. N-type impurity
C. Acceptor impurity
D. Donor impurity
C. Acceptor impurity
“How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?”
A. They are both low impedance
B. An FET has lower input impedance
C. An FET has higher input impedance
D. They are both high impedance
C. An FET has higher input impedance
“What is the beta of a bipolar junction transistor?”
A. The frequency at which the current gain is reduced to 0.707
B. The change in collector current with respect to base current
C. The breakdown voltage of the base to collector junction
D. The switching speed
B. The change in collector current with respect to base current
“Which of the following indicates that a silicon NPN junction transistor is biased on?”
A. Base-to-emitter resistance of approximately 6 to 7 ohms
B. Base-to-emitter resistance of approximately 0.6 to 0.7 ohms
C. Base-to-emitter voltage of approximately 6 to 7 volts
D. Base-to-emitter voltage of approximately 0.6 to 0.7 volts
D. Base-to-emitter voltage of approximately 0.6 to 0.7 volts
“What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?”
A. Corner frequency
B. Alpha rejection frequency
C. Beta cutoff frequency
D. Alpha cutoff frequency
D. Alpha cutoff frequency
“What is a depletion-mode FET?”
A. An FET that exhibits a current flow between source and drain when no gate voltage is applied
B. An FET that has no current flow between source and drain when no gate voltage is applied
C. Any FET without a channel
D. Any FET for which holes are the majority carriers
A. An FET that exhibits a current flow between source and drain when no gate voltage is applied
“In Figure E6-1, what is the schematic symbol for an N-channel dual-gate MOSFET?”
A. 2
B. 4
C. 5
D. 6
B. 4
“In Figure E6-1, what is the schematic symbol for a P-channel junction FET?”
A. 1
B. 2
C. 3
D. 6
A. 1
“Why do many MOSFET devices have internally connected Zener diodes on the gates?”
A. To provide a voltage reference for the correct amount of reverse-bias gate voltage
B. To protect the substrate from excessive voltages
C. To keep the gate voltage within specifications and prevent the device from overheating
D. To reduce the chance of static damage to the gate
D. To reduce the chance of static damage to the gate
“What is the most useful characteristic of a Zener diode?”
A. A constant current drop under conditions of varying voltage
B. A constant voltage drop under conditions of varying current
C. A negative resistance region
D. An internal capacitance that varies with the applied voltage
B. A constant voltage drop under conditions of varying current
“What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?”
A. Much higher reverse voltage breakdown
B. More constant reverse avalanche voltage
C. Longer carrier retention time
D. Less forward voltage drop
D. Less forward voltage drop
“What type of bias is required for an LED to emit light?”
A. Reverse bias
B. Forward bias
C. Zero bias
D. Inductive bias
B. Forward bias
“What type of semiconductor device is designed for use as a voltage-controlled capacitor?”
A. Varactor diode
B. Tunnel diode
C. Silicon-controlled rectifier
D. Zener diode
A. Varactor diode
“What characteristic of a PIN diode makes it useful as an RF switch?”
A. Extremely high reverse breakdown voltage
B. Ability to dissipate large amounts of power
C. Reverse bias controls its forward voltage drop
D. Low junction capacitance
D. Low junction capacitance
“Which of the following is a common use of a Schottky diode?”
A. As a rectifier in high current power supplies
B. As a variable capacitance in an automatic frequency control circuit
C. As a constant voltage reference in a power supply
D. As a VHF/UHF mixer or detector
D. As a VHF/UHF mixer or detector
“What is the failure mechanism when a junction diode fails due to excessive current?”
A. Excessive inverse voltage
B. Excessive junction temperature
C. Insufficient forward voltage
D. Charge carrier depletion
B. Excessive junction temperature
“Which of the following is a Schottky barrier diode?”
A. Metal-semiconductor junction
B. Electrolytic rectifier
C. PIN junction
D. Thermionic emission diode
A. Metal-semiconductor junction
“What is a common use for point-contact diodes?”
A. As a constant current source
B. As a constant voltage source
C. As an RF detector
D. As a high-voltage rectifier
C. As an RF detector
“In Figure E6-2, what is the schematic symbol for a light-emitting diode?”
A. 1
B. 5
C. 6
D. 7
B. 5
“What is used to control the attenuation of RF signals by a PIN diode?”
A. Forward DC bias current
B. A sub-harmonic pump signal
C. Reverse voltage larger than the RF signal
D. Capacitance of an RF coupling capacitor
A. Forward DC bias current
“What is the function of hysteresis in a comparator?”
A. To prevent input noise from causing unstable output signals
B. To allow the comparator to be used with AC input signals
C. To cause the output to change states continually
D. To increase the sensitivity
A. To prevent input noise from causing unstable output signals
“What happens when the level of a comparator’s input signal crosses the threshold?”
A. The IC input can be damaged
B. The comparator changes its output state
C. The comparator enters latch-up
D. The feedback loop becomes unstable
B. The comparator changes its output state
“What is tri-state logic?”
A. Logic devices with 0, 1, and high-impedance output states
B. Logic devices that utilize ternary math
C. Low-power logic devices designed to operate at 3 volts
D. Proprietary logic devices manufactured by Tri-State Devices
A. Logic devices with 0, 1, and high-impedance output states
“Which of the following is an advantage of BiCMOS logic?”
A. Its simplicity results in much less expensive devices than standard CMOS
B. It is immune to electrostatic damage
C. It has the high input impedance of CMOS and the low output impedance of bipolar transistors
D. All these choices are correct
C. It has the high input impedance of CMOS and the low output impedance of bipolar transistors
“What is an advantage of CMOS logic devices over TTL devices?”
A. Differential output capability
B. Lower distortion
C. Immune to damage from static discharge
D. Lower power consumption
D. Lower power consumption