E6A Semiconductor materials and devices: semiconductor materials; bipolar junction transistors; operation and types of field-effect transistors

- [[E6A01]] (C)
In what application is gallium arsenide used as a semiconductor material? #card
	- [[A.]] In high-current rectifier circuits
	- [[B.]] In high-power audio circuits
	- [[C.]] In microwave circuits
	- [[D.]] In very low-frequency RF circuits
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- [[E6A02]] (A)
Which of the following semiconductor materials contains excess free electrons? #card
	- [[A.]] N-type
	- [[B.]] P-type
	- [[C.]] Bipolar
	- [[D.]] Insulated gate
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- [[E6A03]] (C)
Why does a PN-junction diode not conduct current when reverse biased? #card
	- [[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
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- [[E6A04]] (C)
What is the name given to an impurity atom that adds holes to a semiconductor crystal structure? #card
	- [[A.]] Insulator impurity
	- [[B.]] N-type impurity
	- [[C.]] Acceptor impurity
	- [[D.]] Donor impurity
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- [[E6A05]] (C)
How does DC input impedance at the gate of a field-effect transistor (FET) compare with that of a bipolar transistor? #card
	- [[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
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- [[E6A06]] (B)
What is the beta of a bipolar junction transistor? #card
	- [[A.]] The frequency at which the current gain is reduced to 0.707
	- [[B.]] The change in collector current with respect to the change in base current
	- [[C.]] The breakdown voltage of the base-to-collector junction
	- [[D.]] The switching speed
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- [[E6A07]] (D)
Which of the following indicates that a silicon NPN junction transistor is biased on? #card
	- [[A.]] Base-to-emitter resistance of approximately 6 ohms to 7 ohms
	- [[B.]] Base-to-emitter resistance of approximately 0.6 ohms to 0.7 ohms
	- [[C.]] Base-to-emitter voltage of approximately 6 volts to 7 volts
	- [[D.]] Base-to-emitter voltage of approximately 0.6 volts to 0.7 volts
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- [[E6A08]] (D)
What is the term for the frequency at which the grounded-base current gain of a bipolar junction transistor has decreased to 0.7 of the gain obtainable at 1 kHz? #card
	- [[A.]] Corner frequency
	- [[B.]] Alpha rejection frequency
	- [[C.]] Beta cutoff frequency
	- [[D.]] Alpha cutoff frequency
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- [[E6A09]] (A)
What is a depletion-mode field-effect transistor (FET)? #card
	- [[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.]] An FET that exhibits very high electron mobility due to a lack of holes in the N-type material
	- [[D.]] An FET for which holes are the majority carriers
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- [[E6A10]] (B)
In Figure E6-1, which is the schematic symbol for an N-channel dual-gate MOSFET? #card
	- [[A.]] 2
	- [[B.]] 4
	- [[C.]] 5
	- [[D.]] 6
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- [[E6A11]] (A)
In Figure E6-1, which is the schematic symbol for a P-channel junction FET? #card
	- [[A.]] 1
	- [[B.]] 2
	- [[C.]] 3
	- [[D.]] 6
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- [[E6A12]] (D)
What is the purpose of connecting Zener diodes between a MOSFET gate and its source or drain? #card
	- [[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 protect the gate from static damage