EDC 2 Flashcards by Dave Molina

The n-type regions in an npn bipolar
junction transistor are

A. collector, base, and emitter
B. base and emitter
C. collector and base
D. collector and emitter

D. collector and emitter

(look at the figure on your EDC 2 album baby)

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For normal operation of an npn
transistor, the base must be

A. positive with respect to the collector
B. negative with respect to the emitter
C. positive with respect to the emitter
D. disconnected

C. positive with respect to the emitter

For NORMAL operation of a transistor,
the B-E junction must be forward-biased. Therefore, for an NPN transistor,since the base is P type and the emitter is N type, for the B-E junction to beforward biased, the base must be more positive with respect to emitter.

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Beta (β) is the ratio of…

A. collector current to emitter current
B. collector current to base current
C. emitter current to base current
D. output voltage to input voltage

B. collector current to base current

Current gain for different BJT
configurations are as follows:
1. alpha = collector current/emitter current
2. beta = collector current/base current
3. gamma = emitter current/base current

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Where does the transistor act like an
open switch?

A. active region
B. inverted region
C. saturated region
D. cut off region

D. cut off region

In cut off region, both the junctions are
reverse biased. The transistor has
practically zero current because the
emitter does not emit charge carriers to the base. So, the transistor acts as open switch.

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Using the load line to answer, under
what condition will be Vce = Vcc?

A. Linear
B. Active
C. Cut-off
D. Saturation

C. Cut-off

At saturation : Vce = Vce(sat) ≈ 0 V
and lc = Ic(sat)
At the active or linear region:
VcE(sat) < Vce < Vcc and 0 < lc <
Ic(sat)
At cut-off: VcE ≈ Vcc and lc ≈0A

(see the fugure at EDC 2 album😚)

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If a certain transistor operates at the middle of the load line, an increase in the base resistance will move the Q point

A. Off the load line
B. Down
C. Nowhere
D. Up

B. Down

Increasing Rg → decreases lg→
decreases lc → Q point will be to a
lower position in the load line

(see the figure at EDC 2 album)

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An n-type semiconductor material

A. requires no doping
B. has trivalent impurity atoms added
C. is intrinsic
D. has pentavalent impurity atoms added

D. has pentavalent impurity atoms added

N-type semiconductor material, is an
extrinsic semiconductor material that is
the product of doping process that
involves adding donor impurities/
pentavalent atoms such as
Phosphorous, Antimony, Arsenic, or
Bismuth to an intrinsic Silicon or Germanium.

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The input impedance of a MOSFET is

A. higher than that of a JFET.
B. No different than that of a JFET
C. lower than that of a JFET.
D. approximately zero ohms.

A. higher than that of a JFET.

Zì(MOSFET) > Zì(JFET)&raquo_space; Zì(BJT)

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If a transistor operates at the middle of the load line, an increase in the current gain will move the Q point

A. Down
B. Up
C. Off the load line
D. Nowhere

B. Up

Increasing β → increases lc→Q point will move upward in the load line

(look at EDC 2 album)

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The point on the DC load line which is
represented by ‘Q’ is called_____

A. cut off point
B. breakdown point
C. operating point
D. cut in point

C. operating point

The point which represents the values of Ic and Vce that exist in a transistor circuit when no signal is applied is called as operating point. This is also called as working point or quiescent point.

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The input of a CB transistor is given
between_____

A. base and collector terminals
B. collector and emitter terminals
C. ground and emitter terminals
D. emitter and base terminals

D. emitter and base terminals

The name of the CB transistor says that
it’s a common based one. The input is
given between the emitter and base
terminals and the output is taken
between collector and base terminals.

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The primary difference between the construction of depletion-type and enhancement-type MOSFETs is

A. the size of the transistor
B. the reverse bias junction
C. All of these choices
D. the absence of the channel

D. the absence of the channel

EMOSFET is a like a normally-OFF
switch. A threshold voltage must be
exceeded by the gate to source voltage in order to create a conductive channel between the source and drain.
Therefore, at VGS still at O V there will be no conductive channel that will be created between the source and the drain.

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In the saturation region the collector-
base junction is _____ -biased and the base-emitter junction is _____ -biased for a transistor.

A. reverse, forward
B. forward, forward
C. reverse, reverse
D. forward, reverse

B. forward, forward

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Where should be the bias point set in order to make transistor work as an amplifier?

A. Cut off
B. Active
C. Saturation
D. Cut off and Saturation

B. Active

To operate transistor as an amplifier, it
requires more current amplification
factor and in cut off and saturation, the current amplification is less, therefore active region is better to fix the Q point.

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The base current is the _____ of the emitter and collector currents.

A. difference
B. sum
C. product
D. None of these choices

A. difference

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In BJT, the outer layers are the _____
sandwiched layer.

A. the same as
B. much smaller than
C. much larger than
D. None of these choices

C. much larger than

(go to your gallery for more EDC 2)

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When does the transistor act like an
open switch?

A. active region
B. saturated region
C. inverted region
D. cut off region

D. cut off region

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If a splash of solder shorts the collector resistor of a CE NPN transistor amplifier configuration, the collector voltage will

A. Double
B. Stay the same
C. Drop to zero
D. Equal the collector supply voltage

D. Equal the collector supply voltage

From the output loop of a CE NPN
transistor: Vcc -IcRc - Vc = 0 If the
collector resistor will be shorted (Rc =0) the equation above can be simplified to: Vc= Vcc.

For a transistor to function as an
amplifier,

A. Both the EB and CB junctions must be
forward-biased.
B. Both the EB and CB junctions must be
reverse-biased,
C. The CB junction must be forward-biased
and the EB junction must be reverse-
biased
D. The EB junction must be forward-
biased and the CB junction must be
reverse-biased.

D. The EB junction must be forward-
biased and the CB junction must be
reverse-biased.

In a CE BJT NPN transistor amplifier, if the emitter resistance decreases, the collector voltage

A. Decreases
B. Increases
C. Breaks down the transistor
D. Stays the same

A. Decreases

In the output loop of a normal CE BJT NPN transistor amplifier: Vc =VcE +lgRE
Therefore if Re increases, Vc will
also increase.

What should be the value of stability
factor to keep the operating point
stable?

A. zero
B. one
C. as high as possible
D. negative value

A. zero

Ideal value of stability factor = 0.

Compared to NPN, the direction of
current is _____ and the polarity of the
voltage is _____ in a PNP transistor.

A. opposite; reverse
B. same; reverse
C. same; forward
D. opposite; forward

A. opposite; reverse

PNP and NPN transistors have different
construction therefore the flow of their
currents are opposite and the polarity of
the voltages required to bias them are
reverse of the other.

An n-channel FETs are better as
compared to p-channel FET because

A. they are more efficient
B. mobility of electrons is more than that
of holes
C. they have high switching time
D. they have higher input impedance

B. mobility of electrons is more than that
of holes

In a transistor, which is the largest of all
the doped regions?

A. The collector region
B. The emitter region
C. The base region
D. The anode region

A. The collector region

In BJTs, collector is the largest
region/layer while the smallest
layer/region is the sandwiched base
region/layer.

(see more at EDC 2 album)

In an N-channel JFET, pinchoff occurs when the gate bias is: A. Zero B. Very negative C. Slightly positive D. Slightly negative

B. Very negative In an N-channel JFET, as the Gate voltage is made more negative, the width of the channel decreases until no more current flows between the Drain and the Source and the FET is said to be "pinched-off" (similar to the cut-off region for a BJT). The voltage at which the channel closes is called the "pinchoff voltage",(VP). For a P-channel JFET, same effect will happen but for an opposite polarity of gate voltage.

In which JFET amplifier are the ac input and output voltages 180° out of phase? A. The common-source amplifier B. The common-gate amplifier C. The source-follower D. The common-drain amplifier

A. The common-source amplifier Input-output phase relationship for different FET amplifier configurations: Common-Gate : 0° or in-phase Common-Drain or Source-Follower : 0° or in-phase Common-Source:180°

In a transistor amplifier, when the Q point moves along the load line, the collector to emitter voltage increases when the collector current_____ A. None of these choices B. Increases C. Stays the same D. Decreases

D. Decreases Moving upward or downward along the load-line above, you will notice that Ic and Vce will vary inversely. (see more at EDC 2 album)

An enhancement-mode MOSFET can be recognized in schematic diagrams by: A. A broken vertical line inside the circle B. An arrow pointing outward. C. An arrow pointing inward D. A solid vertical line inside the circle.

A. A broken vertical line inside the circle. (see the figure in EDC 2 album)

Which is not a MOSFET terminal? A. Drain B..Gate C. Base D. Source

C. Base The three terminals of an FET (both JFET and MOSFET) are GATE, DRAIN,and SOURCE. While for a BJT, the three terminals are BASE, COLLECTOR, and EMITTER.

In an n channel JFET, the gate is A. either n or p B. p type C. partially n & partially p D. n type

B. p type (see the N-Channel figure at EDC 2 album)

an n-channel enhancement type MOSFET, if the source is connected at a higher potential than that of the bulk (VSB > 0), the threshold voltage VT of the MOSFET will A. increase B. decrease C. change Polarity D. remain unchanged

D. remain unchanged V_T depends upon MOSFET construction, hence it will Independent from MOSFET parameters.

The carriers of n channel JFET are A. holes B. free electrons or holes C. free electrons and holes D. free electrons

D. free electrons In n type semiconductors carriers are electrons. Since the JFET has an N-type material in the channel, current flowing from source to drain through channe consists of free electrons only (since FET is a unipolar device).

Compared to bipolar junction transistor, a JFET has A. lower input impedance B. high input impedance and high voltage gain C. higher voltage gain D. high input impedance and low voltage gain

D. high input impedance and low voltage gain In a JFET input is reverse-biased while in BJT the input is forward-biased. Because of this, a JFET will have a higher input impedance but a lower voltage gain compared to a BJT.

Which of the following devices has a silicon dioxide layer? A. JFET B. NPN transistor C. Tunnel diode D. MOSFET

D. MOSFET In MOSFETs (both depletion type and enhancement type) the gate is insulated from the channel by a layer of an insulating material called Silicon Dioxide or Si02.

The primary advantage that MOSFET transistors have over bipolar transistors is_____. A. higher switching speed B. reduced propagation delay C. high input impedance D. low input impedance

C. high input impedance A MOSFET has a higher input impedance compared to a BJT since in MOSFET there is an insulating material between the gate and the channel.

In a C-E configuration, an emitter resistor is used for: A. stabilization B. higher gain C. collector bias D. ac signal bypass

A. stabilization Adding an emitter resistor increases the stability but decreases the gain of a BJT CE amplifier.

The symbol shown is for a... (go to EDC 2 album) A. N-channel DMOSFET B. P-channel DMOSFET C. N-channel JFET D. P-channel JFET

A. N-channel DMOSFET

Assertion (A): Two transistors one n-p-n and the other p-n-p are identical in all respects (doping, construction, shape, size). The n-p-n transistor will have better frequency response. Reason (R): The electron mobility is higher than hole mobility. A. A is true but R is false B. Both A and R are true and R is correct explanation of A C. Both A and R are true but R is not a correct explanation of A D. A is false but R is true

B. Both A and R are true and R is correct explanation of A NPN transistor will have a better frequency response due to the fact that majority of the carriers in NPN are free electron and free electrons have higher mobility than holes making the NPN transistor more able to operate satisfactorily at higher frequencies.

As the temperature increases, β _____, VBE _____, and lco _____ in value for every 10°C. A. decreases, increases, remains the same B. increases, decreases, doubles C. increases, increases, triples D. decreases, increases, doubles

B. increases, decreases, doubles As the temperature increases, β increases, VBE decreases, and lco doubles in value for every 10°C

Which of the following applies to a safe MOSFET handling? A. Power should always be off when network changes are made. B. Always pick up the transistor by the casing. C. All of these choices. D. Always touch ground before handling the device.

C. All of these choices MOSFETs are sensitive to electrostatic discharge(ESD). Depending on the energy of the pulse, electrostatic discharge (ESD) may cause either catastrophic failure (gate-oxide breakdown) or non-catastrophic damage (degradation) to MOSFETs.

Assertion (A): A JFET behaves as a resistor when VGS < VP. Reason (R): When VGS< VP, the drain current in a JFET is almost constant. A. Both A and R are true and R is correct explanation of A B. A is true but R is false C. A is false but R is true D. Both A and R are true but R is not a correct explanation of A

B. A is true but R is false Ohmic region: in this region FET is used as a variable resistor. Saturation or Active region: in this region the FET is used for small signal amplification. Breakdown region: operating in this region may destroy the FET.

The drain of FET is analogous to BJT A. base B collector C. emitter D. drain

B collector Relation between BJT and FET terminals: Base →→ Gate Collector → Drain Emitter → Source

Which of the following is the other name for Common Drain Amplifier? A. Current Booster B. Voltage limiter C. Voltage booster D. Source Follower

D. Source Follower Just like in BJT configurations, Common Collector is also called Emitter follower.

The disadvantage of base bias is that A. it is too beta dependent B. it is very complex C. it produces high leakage current D. it produces low gain

A. it is too beta dependent Base-bias or Fixed-bias in BJT amplifiers provides the highest gain but is the most stable (parameter values are too beta dependent which can be easily affected by changes in temperature).