compiled elecs qa

5/23/2018 Compiled Elecs Qa

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QUESTION:A type of oscillator which uses an amplifier circuit thatintroduces 1800phase shift

Choices:

a. RC Phase Shift Oscillatorb. Wien Bridge Oscillatorc. Hartley Oscillator

d. Armstrong Oscillator

Answer: A

QUESTION:A type of Oscillator that is very commonly used as localoscillator in superheterodyne radio receiver

Choices:a. RC Phase Shift Oscillatorb. Colpitts Oscillatorc. Clapp Oscillatord. Wien Bridge Oscillator

ANSWER: A. Colpitts Oscillator

QUESTION:The measure of how pure or real an inductor is. The higherits value in an inductor, the fewer losses there are.

Choices:a. Q-factorb. Beta Factorc. Alpha Factord. K-factor

ANSWER:

a. Q-factorQUESTION:This can be defined as the ratio of output d.c. power availableat the load to the power rating (Volt Ampere) of thetransformer used in the rectifier circuit

Choices:a. Transformer Utilization Factorb. Transformer Form Factorc. Transformer Load Voltage Factord. Transformer Working Factor

ANSWER:a. Transformer Utilization Factor

QUESTION:A type of flip-flop in which the data are entered and appear onthe output on the same clock edge.

Choices:a. Set Reset Flip flopb. Edge Triggered Flip flopc. JK Flip flopd. D Flip flop

ANSWER:b. Edge Triggered Flip flop

QUESTION:If the feedback signal (voltage or current) is applied in such away that it is in phase with the input signal and thusincreases. It is also known as regenerative feedback or directfeedback

Choices:a. Positive Feedbackb. Negative Feedbackc. Stabilized Feedback

d. Impedance FeedbackANSWER:

a. Positive Feedback

QUESTION:Refers to the process of shrinking the size and powerdissipation of electronic circuits. It also involves surface mounttechnology

Choices:a. Gull wingb. Microminiaturizationc. Floating Pointd. Synchronous Deviation

ANSWER:a. Microminiaturization

QUESTION:A non-volatile read/write random access semiconductomemory in which data are stored as charge on the floagate of a certain type of FET

Choices:a. PROM b. Hard Disk c. Flash Memory d.

ANSWER:a. Flash Memory

QUESTION:It is a channel model in which the input and outputalphabets x and y are discrete sets and the channel ismemoryless

Choices:a. The Discrete Memory Channelb. The Discrete channelc. The Discrete Memoryless Chaneld. None of the above

ANSWER:C. The Discrete Memoryless Chanel

QUESTION:It is a diagnostic application or device that a networkadministrator can purchase and install on a networkworkstations or attach to the network media to monitoand capture dat packets for subsequent analysis..

Choices:a. Snifferb. Splatterc. Clipper

d. ClamperANSWER:

a. Sniffer

QUESTION:_______________ is a secret key encryption technolothat is used in client/server environments for secureauthentication between computers

Choices:a.Kepberosb. Kerberosc. Kesberosd. None of the above

ANSWER:b. Kerberos

QUESTION:What is the circuit which has a purpose to quiet a recein the absence of a received signal?

Choices:a. Squilch circuitb.Squealch circuit

c. Squelch circuitd. Squeltch circuit

ANSWER:c. Squelch circuit

QUESTION:What is network node dedicated to interfacing betweennetwork and one or more printers?

Choices:a. Print serverb. Lay-out Server

c. Tune serverd. All of the above

ANSWER:a. Print server

QUESTION:What is formed on the screen of cathode ray oscilloscowhen two sine wave voltages are simultaneously appliethe two sets of deflection plates?

Choices:a. Lizzajous patternb. Lisajous patternc .Lissajous patternd. Lizajous pattern

ANSWER: C. Lissajous pattern


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QUESTION:A type of circuit that consists of two matching transistors withthe collector of one connected to the bases of both, thusproducing the same collector current in each transistor.

Choices:a. currentlimiting

b. currentmirror

c. Darlingtonpair

d. equivalentcircuit

ANSWER:B. current mirror

QUESTION:Determine the cut-off frequency of an op-amp having unitybandwidth of 1MHz and open loop gain of 200 V/mV.

Choices:a. 0.2 Hz b. 0.5 Hz c. 5 Hz d. 1 MHz

ANSWER:C. 5 Hz

SOLUTION ( IF PROBLEM -SOLVING)

QUESTION:

In a push-pull amplifier, the distortion in the output cause by

the transition of state of transistors from cut-off state to the on

state is called ____.

Choices:

a. harmonic

distortion

b. crossover

distortion

c. clipping d. aliasing

ANSWER:

B. crossover distortion

QUESTION:

For an op-amp having a slew rate of 2 V/us, what is the

maximum closed-loop voltage gain that can be used when the

input signal varies by 0.5 V in 10 us?

Choices:

a. 10 b. 20 c. 30 d. 40

ANSWER:

D. 40


QUESTION:A certain voltage regulator has a 12 V output when there is noload. When there is a full-load current of 10 mA, the outputvoltage is 11.9 V. What is the voltage regulation? Express in%/mA.

Choices:a. 0.00084%/mA

b. 0. 0084%/mA

c. 0.084%/mA

d. 0.84%/mA

ANSWER:C. 0.084 %/mA


QUESTION:A class C amplifier is driven by a 200 kHz signal. The transis on for 1us, and the amplifier is operating over 100 perceits load line. If IC(sat) = 100 mA and VCE(sat) = 0.2 V, whthe average power dissipation of the transistor?

Choices:a. 20 mW b. 2 mW c. 40 mW d. 4 mW

ANSWER:D. 4 mW


QUESTION:The nominal output voltage of a certain regulator is 8 V. Toutput changes 2 mV when the input voltage foes from 12 18 V. Determine the line regulation and express it in units %/V.

Choices:a. 0.004167%/V

b. 0.033333%/V

c. 0.155556%/V

d. 0.266%/V

ANSWER:A. 0.004167 %/V


QUESTION:What is VOUT for a transistor log amplifier with VIN = 3 V R1 = 68 k? Assume IEBO = 40 nA.

Choices:a. 1.751 mV b. -1.751 mV c. 175.1 mV d. -175.

ANSWER:D. -175.1 mV


QUESTION:In a self-biased JFET, the gate is at

Choices:a. a positivevoltage

b. 0 V c. a negativevoltage

d. groun

ANSWER:B. 0 V

QUESTION:It is the time taken by a diode to operate in the reversecondition from forward conduction.

Choices:a. reverserecoverytime

b. transitiontime

c. storagetime

d. respontime

ANSWER:A. reverse recovery time

QUESTION:The MOSFET in a certain single-stage common-source amphas a range of forward transconductance values from 2.5 m7.5 mS. If the amplifier is capacitively coupled to a variablthat ranges from 4 k to 10 k and the dc drain resistanc1.0k, Determine the maximum voltage gain.

Choices:a. 2.0 b. 3.53 c. 4.67 d. 6.82

ANSWER:D. 6.82


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SOLUTION ( IF PROBLEM -SOLVING) QUESTION:This diode provides fast voltage transitions by the very suddendisappearance of the charge carriers. After a forward currenthas been passing in the diode and the current is interrupted, thereverse conduction will cease very abruptly.

Choices:a. Schottkydiode

b. Step-recoverydiode

c. Tunneldiode

d. Pointcontactdiode

ANSWER:

B. Step-recovery diodeQUESTION:What theory states that "any resistance R in a branch of anetwork in which a current I is flowing can be replaced by avoltage equal to IR"?

Choices:a. SourceTransformation

b.Norton'sTheorem

c.SuperpositionTheorem

d.CompensationTheorem

ANSWER:D. Compensation Theorem

QUESTION:The resonant circuit of a tuned-collector transistor oscillator hasa resonant frequency of 5 MHz. If the value of capacitance isincreased by 50%. Calculate the new resonant frequency.

Choices:a. 3.33 MHz b. 2.6 MHz c. 11.25 MHz d. 4.08 MHz

ANSWER:D. 4.08 MHz


()

QUESTION:For a silicon diode, calculate the current at room temperature ifthe forward voltage, Vf = 0.3 V and the reverse saturationcurrent Is = 100 nA. Use thermal voltage of 0.025 V.

Choices:a. 8.69 mA b. 16.28 mA c. 8.69 nA d. 16.28 nA

ANSWER:B. 10.51 m


QUESTION:A BUZ73L MOSFET has an on resistance of 0.4 OHMS and israted at 7 A. If the supply voltage is 9 V, what is the minimumresistance of a device in series that it can safely switch?

Choices:a. 1.286 ohmsb. 0.886 ohmsc. 0.486 ohms

d. 0.4 ohmsANSWER:b. 0.886 ohms

SOLUTION ( IF PROBLEM -SOLVING)9=7(0.4 + R)R = 0.886 ohmsQUESTION:What is the minimum contact rating for a relay required toswitch a 1000 W, 230 V floodlamp?

Choices:a. 4.35 A b. 2.09A c. 1.04A d. 18.9mA

ANSWER:a. 4.35 A

SOLUTION ( IF PROBLEM -SOLVING)P=VI; 1000 = 230 I

I = 4.35 A

QUESTION:When the gate-source voltage of a given MOSFET increaseV, the drain current increases by 1.7 A. What is thetransconductance of the MOSFET?

Choices:a. 3.4 mho b. 1.31 mho c. 0.85 Siemens d. 0.59

ANSWER:c. 0.85 Siemens

SOLUTION ( IF PROBLEM -SOLVING)gm=id/vgs = 1.7A/2V = 0.85 S

QUESTION:A capacitor is charged by connecting it to a 3 V DC supplythen holds 1.5 coulombs of charge. What is its capacitance

Choices:a. 6 Farad b. 4 Farad c. 0.5 Farad d. 0.25 Fara

ANSWER:c. 0.5 Farad

SOLUTION ( IF PROBLEM -SOLVING)C=Q/V = 1.5 / 3V = 0.5 F

QUESTION:A 555 monostable circuit has R1 = 2.2 kOHMS and C1= 1.What is the length of the output pulse?

Choices:a. 2.079milliseconds b. 2.310ms c. 2.970 ms d. 3.630

ANSWER:d. 3.630 milliseconds

SOLUTION ( IF PROBLEM -SOLVING)T = 1.1 R1 C1= 1.1(2.2k ohms)(1.5 x10exp-6) =3.63milliseconds

QUESTION:A 555 astable has R1=10 kOHMS, R2=6.8 kOHMS and C1=nF. What is the frequency and the mark-space ratio of theoutput signal?

Choices:a. 406.78Hz b. 571.43Hz c. 273.81Hzd. 194.92 Hz

ANSWER:a. 406.78Hz

SOLUTION ( IF PROBLEM -SOLVING)F = 1.44 /(C1(R1+2R2) = 1.44/ (150nF(10k+2(6.8k)) =406.78Hz

QUESTION:

At what frequency does a 220 nF capacitor have an impedof 2.2 kOHMS?

Choices:a. 22,727.27 Hz b. 1,033.06 Hz c. 657.67 Hz d. 328.83

ANSWER:d. 328.83 Hz

SOLUTION ( IF PROBLEM -SOLVING)Xc = 1/ (2pifC) = 2.2k ohms = 1/(2*3.14*f*220nF)f = 328.83 Hz

QUESTION:A highpass filter has R=470 OHMS and C=2.2 F. What is impedance of the capacitor at 10 kHz?

Choices:a.7.23 ohms b. 21.28 ohms c. 213.64 ohms 470 ohms

ANSWER:a.7.23 ohms

SOLUTION ( IF PROBLEM -SOLVING)XC= 1/(2pifC) = 7.23 OHMS

QUESTION:A 50 mW signal is amplified to 300 mW, what is the gain inat cut-off frequency?

Choices:a. 7.78 dB b. 4.78dB c. 1.78 dB d. 0.707

ANSWER:b. 4.78dB


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SOLUTION ( IF PROBLEM -SOLVING)Ap(cutoff) = Ap *0.5Ap(cutoff) dB= 10log(Ap * 0.5) = 10 log (0.5*300mW/50mW)Ap(cutoff) dB=4.78dB

QUESTION:A signal of amplitude 60 mV is amplified to 500 mV, what is thegain at critical frequency?

Choices:a.11.78 b. 8.33 c. 5.89 d. 4.17

ANSWER:c. 5.89


Av(cutoff) = Av* 0.707 = 500mV/60mV*0.707 = 5.89QUESTION:The current in a coil begins to fall at the rate of 6 A/s. If L = 840mH, what emf is produced in the coil?

Choices:a. 2.52V b. 3.56V c. 5.04V d. 14V

ANSWER:c. 5.04V

SOLUTION ( IF PROBLEM -SOLVING)VL = L(di/dt) = 840mH(6A/s)VL = 5.04V

QUESTION:If the transistor in the CE amplifier has hfe = 120, what is theinput resistance?

Choices:a. 2 kohms b. 2.4 kohms c. 2.7 kohms d. 3k ohms

ANSWER:d. 3 kohms

SOLUTION ( IF PROBLEM -SOLVING)Rin 120(25) = 3 k ohms

QUESTION:In a voltage divider bias, common-emitter amplifier with R1=240kohms , R2 = 33 kohms , RC = 7.5 kohms and RE = 1kohms, the expected voltage gain is___.

Choices:a. 288 b. 144 c. 33 d. 7.5

ANSWER:d. 7.5

SOLUTION ( IF PROBLEM -SOLVING)Av Rc/RE = 7.5k/1k = 7.5

QUESTION:A transistor has an hfe of 80. When the base current isincreased by 15 A, the collector current increases by____.

Choices:a.15mA b. 1.2mA c. 1mA d. 15uA

ANSWER:b. 1.2mA

SOLUTION ( IF PROBLEM -SOLVING)hfe= change in collector current / change in base current.80 = change in collector current / 15uAic = 1.2mA

QUESTION:If the open-loop gain is 20 at 100 kHz, it is 10 at 200 kHz, 5 at

400 kHz, and so on to a gain of 1 at 2 MHz. Compute the gain-bandwidth product of the op-amp.

Choices:a. 6 MHz b. 3 MHz c. 2 MHz d. 1.5 MHz

ANSWER:c. 2 MHz

SOLUTION ( IF PROBLEM -SOLVING)GBP=AvBw=Avfc=20(100kHz)=10(200kHz)=5(400kHz)=2 MHz

QUESTION:Calculate the best value for RB(compensating resistor) for aninverting amplifier in which RA=2.2 kohms(input component)and RF=820 kohms(feedback component).

Choices:a. 822.2 kohms b. 820 kohms c. 2.2 kohms dkohms

ANSWER:c. 2.2 kohms

SOLUTION ( IF PROBLEM -SOLVING)Rb = RA(RF)/(RA+RF)=2.19 k ohms

QUESTION:The open-loop gain of an op amp falls to 1 at___.

Choices:a. 1Mhz b. 5MHz c. 10 MHz d. transitionfrequency

ANSWER:d. transition frequency

QUESTION:The input resistor of a non-inverting op amp is 39 kohms athe feedback resistor is 1.2 Mohms. The output voltage isV. The input voltage is:

Choices:a. 15.74mV b. +15.74mV c. 16.25mV +16.25mV

ANSWER:a. 15.74mV

SOLUTION ( IF PROBLEM -SOLVING)Av=(1+ RF/RA)=Vo/Vi = (1+1M/39k)= - 0.5V / ViVi = 15.74mV

QUESTION:If the input voltage is constant at 20 mV, R is 10 kOHMS ais 470 nF, what is output voltage of an integrator after 25

Choices:a. - 3.76 mV b. 9.4 mV c. - 14.14mV d. - 106.38 m

ANSWER:d. - 106.38 mV

SOLUTION ( IF PROBLEM -SOLVING)Vout(@25ms) = -Vin * t/(RC)= -20mV(25msec)/(10k*470106.38 mV

QUESTION:At the cut-off point of a lowpass filter the phase change is

Choices:a. +90 degree b. 0 degree c. 45 degree d. degree

ANSWER:c. 45 degree

QUESTION:An active bandpass filter is built from a lowpass filter cascawith a highpass filter. It has a lower cutoff frequency of 20and a bandwidth of 800 Hz. The cutoff points of its two filtare:

Choices:a. lowpass = 200 Hz, highpass = 1 kHz.b. lowpass = 1 kHz, highpass = 200 Hz.c. lowpass = 200 Hz, highpass = 800 Hz.d. lowpass = 800 Hz, highpass = 1 kHz.

ANSWER:a. lowpass = 200 Hz, highpass = 1 kHz

QUESTION:

The metal tag of a power transistor operating at 2.2 W is adegree Celsius. It is bolted to a heat sink and the ambienttemperature (inside the circuit enclosure) is 35 degree CelWhat is the thermal resistance of the heat sink?

Choices:a. 40.91 C/W b. 25 C/W c. 15.9 C/W d. 1.17

ANSWER:b. 25 C/W


Thermal resistance = (90-35)/2.2 = 25 C/W

QUESTION:A snubber network is used to reduce___.


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Choices:a. overheating of the triac.b. RFI.c. the length of the trigger pulse.d. false triggering.

ANSWER:d. false triggering.

QUESTION:The outputs of a full adder are S = 0, Co = 1. Its inputs mightbe____.

Choices:A. A = 1, B = 0, Ci = 0.

B. A = 1, B = 1, Ci = 1.C. A = 1, B = 0, Ci = 1.D. A = 0, B = 0, Ci = 0.

ANSWER:C. A = 1, B = 0, Ci = 1.

QUESTION:An op amp adder is used as a digital-to-analogue converter. Theinput resistor for D0 is 15 kohms. The input resistor for D2 is:

Choices:a. 30 kOHMS b. 15 kOHMS c. 7.5 kOHMS d. 3.75 kOHMS

ANSWER:d. 3.75 kOHMS

SOLUTION ( IF PROBLEM -SOLVING)R0=16RF=2R1=15kohmsR1=8RF=2R2=7.5kohms

R2=4RF=2R3=3.75kohmsR3=2RF

QUESTION:A phenomenon that occurs for large reverse voltages across a

pn junction where the free electrons are accelerated to suchhigh speeds that they can dislodge valence electrons.

a. Piezoelectric effectb. Zener Effectc. Recombinationd. Avalanche effect

ANSWER: d. Avalanche effect

QUESTION:A graph showing the gain or phase performance of an electroniccircuit at various frequencies.

a. Ogive graph

b. Bode plotc. Gain-frequency curved. Performance graph

ANSWER: b. Bode plot

QUESTION:What do you call the ohmic resistance of the semiconductor?

a. Dynamic resistanceb. Static resistancec. Bulk resistanced. Semiconductor resistance

ANSWER: c. Bulk resistance

QUESTION:The metaphor used to describe the action of an SCR when it isused to protect a load against supply.

a. Surgeb. Limiterc. Breakerd. Crowbar

ANSWER: d. Crowbar

QUESTION:A value that tells you how much to reduce the power rating foreach degree above the reference temperature given on the data

sheet.

a. Reduction factorb. Derating factorc. Temperature coefficientd. Attenuation

ANSWER: b. Derating factor

QUESTION:It is the process of adding impurity element to an intrinsicsemiconductor to change its conductivity.

a. Impurificationb. Crystallizationc. Recombinationd. Doping

ANSWER: d. Doping

QUESTION:A condition where the transistor is operating at the upper ethe load line with a base current that is one-tenth of thecollector current.

a. Full saturationb. Hard saturationc. Mid saturationd. Avalanche

ANSWER: b. Hard saturation

QUESTION:A connection of two transistors connected with positive feeto simulate the action of a thyristor.

a. Complementaryb. Latchc. Push pulld. Switch

ANSWER: b. Latch

QUESTION:It refers to the average amount of time between the creatiand recombination of a free electron and a hole.

a. Recombination timeb. Delay timec. Conduction timed. Life time

ANSWER: d. Life time

QUESTION:A filter that blocks a signal with at most one frequency.

a. Brick wall filterb. Cauer filterc. Notch filterd. Butterworth filter

ANSWER: c. Notch filter

QUESTION:

A term use to describe the death of amplification.a. Oscillationb. Attenuationc. Degradationd. Hysteresis

ANSWER: a. Oscillation

QUESTION:The voltage that provides the border between the ohmic reand the constant current region of a depletion-mode devicwhen the gate to source voltage is zero.

a. Threshold voltageb. Peak point voltagec. Valley point voltaged. Pinch off voltage

ANSWER: d. Pinch off voltage

QUESTION:A basic circuit that a designer can modify to get more advacircuits.

a. Model circuitb. Miniature circuitc. Prototyped. Hybrid

ANSWER: c. Prototype

QUESTION:It is a comparator with hysteresis.

a. Schmitt triggerb. Hysteresis circuitc. Trigger-comparatord. Latch circuit

ANSWER: a. Schmitt trigger


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QUESTION:Which of the following special purpose diode doesnt havedepletion layer?

a. Tunnel diodeb. Schottky diodec. Varactor dioded. Zener diode

ANSWER: b. Schottky diode

QUESTION:It is define as a large initial current that flows through the diodeof a rectifier.

a. Bleeder current

b. Surge currentc. Transient currentd. Saturated current

ANSWER: b. Surge current

QUESTION:It is defined as a four-layer semiconductor device that acts as alatch.

a. Thyrectorb. Transistorc. Transformerd. Thyristor

ANSWER: d. Thyristor

QUESTION:It is the value of the input voltage that switches the output of acomparator.

a. Triggerb. Trip pointc. Latchd. Knee

ANSWER: b. Trip point

QUESTION:It is a device that acts like two back-to-back-zener diodes.

a. Varistorb. Varactorc. Complementary zenerd. Zener latch

ANSWER: a. Varistor

QUESTION:

What do you call a thin slice of crystal used as a chassis forintegrated components.

a. Substrateb. Basec. Waferd. Impurity

ANSWER: c. Wafer

QUESTION:What is the other term for zener effect?

a. Avalanche effectb. Piezoelectric effectc. High field emissiond. Breakdown effect

ANSWER: c. High field emission

QUESTION:Calculate the efficiency of a transformer-coupled class Aamplifier for a supply of 12 V and outputs of 6V.

a. 50% b. 25% c. 12.5% d. 10%

ANSWER: c. 12.5%


Resulting in

QUESTION:For a class B amplifier providing a 20-V peak to a 16-loa(speaker) and a power supply of Vcc = 30 V, determine thcircuit efficiency.

a. 45.2% b. 66.67% c. 78.5% d. 52.3%

ANSWER: d. 52.3%


For resulting efficiency of

QUESTION:For a class B amplifier using a supply of Vcc = 30 V and dra load of 16,determine the maximum output power.

a. 28.13W b. 35.81W c. 41.23W d. 54.91W

ANSWER: b.35.81W


Maximum

QUESTION:For a class B amplifier using a supply of Vcc = 30 V and dra load of 16,determine the transistor dissipation

a. 3.7W b. 4.7W c. 5.7W d. 6.7W

ANSWER: c. 5.7W


Maximum

*

QUESTION:Calculate the efficiency of a class B amplifier for a supply o= 24 V with peak output voltages of VL (p) = 22 V.

a. 62% b. 68% c. 72% d. 78%

ANSWER: c. 72%


a. QUESTION:Calculate the total harmonic distortion for the followingamplitude components: fundamental amplitude of 2.5 V, sharmonic amplitude of 0.25 V, third harmonic amplitude oV, and fourth harmonic amplitude of 0.05 V.

a. 11% b. 12% c. 13% d. 14%

ANSWER: a. 11%

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QUESTION:Determine what maximum dissipation will be allowed for an 80-W silicon transistor (rated at25) if the reading is requiredabove 25by a derating factor of 0.5W/at case temperatureof 125.

a. 25W b. 30W c. 35W d. 40W

ANSWER: b. 30W

SOLUTION ( IF PROBLEM -SOLVING) QUESTION:

A silicon power transistor is operated with a heat sink the transistor, rated at150 W ,and the mounting insulation has . What maximumpower can be dissipated if the ambient temperatureis

a. 61.5W b. 71.5W c. 81.5W d. 91.5W

ANSWER: a. 61.5W


QUESTION:A dc voltage supply provides 50 V when the output is unloaded.

When connected to a load, the output drops to 56 V. Calculatethe value of voltage regulation.

a. 4.1% b. 7.1% c. 5.7% d. 10.7%

ANSWER: b. 7.1%


QUESTION:Calculate the ripple voltage of a full-wave rectifier with a 100-Ffilter capacitor connected to a load drawing to a load drawing 50mA

a. 1.2V b. 2.5V c. 2.7V d. 3.1V

ANSWER: a. 1.2V


QUESTION:Calculate the filter dc Voltage of a full-wave rectifier with a 100-F filter capacitor connected to a load drawing to a load drawing50 mA if the peak rectifier voltage is 30 V.

a. 25.4V b. 26.1V c. 27.9V d. 28.6V

ANSWER: c. 27.9V


QUESTION:Calculate the ripple of a capacitor filter for a peak rectifiedvoltage of 30 V, capacitor C= 100F, and a load current of 50mA.

a. 3.7% b. 4.3% c. 5.1% d. 6.9%

ANSWER b. 4.3%


QUESTION:Calculate the input bias currents at the non-inverting andinverting terminal respectively of an op=amp having specified

values of IIO = 5nA and IIB = 30 nA.

a. Both 32.5nA b. Both 27.5nA c. 27.5nA; 32.5nA32.5nA; 27.5nA

ANSWER: d. 32.5nA; 27.5nA


QUESTION:Determine the cutoff frequency of an op-amp having specivalues B1 = 1 MHz and AVD = 200 V/mV.

a. 4Hz b. 5Hz c. 1kHz d. 1MHz

ANSWER: b. 5Hz


QUESTION:For an op-amp having a slew rate of SR = 2V/s, what is tmaximum closed loop voltage gain that can be used when input signal varies by 0.5 V in 10 s?

a. 10 b. 20 c. 30 d. 40

ANSWER: d. 40


QUESTION:

Determine the output voltage of an op-amp for input voltaVi1 = 150 V and Vi2 = 140 V. The amplifier has a differegain of Ad =4000 and the value of CMRR is 100.

a. 32.6mV b. 45.8mV c. 51.9mV d. 66.7mV

ANSWER: b. 45.8mV


QUESTION:If an amplifier with gain of -1000 and feedback of =-0.1 gain change of 20% due to temperature; calculate the chagain of the feedback amplifier

a. 10% b. 0.2% c. 20% d. 1%

ANSWER b. 0.2%


| | (20%) = 0.2%


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QUESTION:A transistor has a collector current of 10mA and a base currentof 40uA. What is the current gain of the transistor

a. 20 b. 30 c. 40 d. 50

ANSWER: d. 50

SOLUTION ( IF PROBLEM -SOLVING)=10mA/40uA=50

QUESTION:A 2N3904 has VCE=10V and IC=20mA. What is the powerdissipation?

a. 0W b. 100mW c. 200mW d. 2N3904 is limitedto 10mW

ANSWER: c. 200mW

SOLUTION ( IF PROBLEM -SOLVING)PD=10V(20mA)=200mW

QUESTION:A zener regulator has an input voltage that may vary from 22 to30V. If the regulated output voltage is 12V and the loadresistance varies from 140 to 10k, what is the maximumallowable series resistance?

a. 140 b. 76.4 c. 280 d. 117

ANSWER: d. 117


QUESTION:It is sometimes called hot-carrier diode.

a. Shockley diodeb. Schottky diodec. Gunn Dioded. Tunnel diode

ANSWER: b. Schottky diode

QUESTION:A zener regulator has an input voltage ranging from 15 to 20Vand a load current ranging from 5 to 20mA. If the zener voltageis 6.8V, what is the maximum allowable series resistance?

a. 750 b. 410 c. 1000 d. 2000

ANSWER b. 410


QUESTION:A 2N5668 has VGS(off)=-4V and IDSS=5mA. What are the gatevoltage and drain current at the half cutoff point?

a. -1V; 1mA b. -2V; 1.25mA c. -4V; 5mA d. 0; 0

ANSWER: b. -2V; 1.25mA


QUESTION:A network that employ diodes to remove away a portion of aninput signal without distorting the remaining part of the appliedwaveform

a. Clamperb. Rectifierc. Regulatord. Clipper

ANSWER: d. clipper

QUESTION:The time required for the minority carriers to return to themajority carrier state in the opposite material.

a. Transition timeb. Time constantc. Rise timed. Storage time

ANSWER: d. Storage time

QUESTION:Determine the thermal voltage of a diode at 27C (commotemperatures for components in an enclosed operating sys

a. 20mV b. 26mV c. 30mV d. 1V

ANSWER: b. 26mV


Vt =kT/q=(1.38x10-23J/K)(273+17)/1.6x10-19C= 26mV

QUESTION:What is the knee voltage of a silicon diode at 75C?

a. 0.7V b. 2.1V c. 0.58V d. 0V

ANSWER: c. 0.58V

SOLUTION ( IF PROBLEM -SOLVING)(75-25)C*2.5mV/C = 0.125V

New Vknee = 0.7-0.125 = 0.575V

QUESTION:At 20C, the reverse saturation current of a silicon diode is10nA, what is its value when the temperature increases to100C?

a. 0.32uA b. 50nA c. 10nA d. 0A

ANSWER: a. 0.32uA

SOLUTION ( IF PROBLEM -SOLVING)100 C / 20C = 5New Ireverse = 25(10nA)= 0.32uA

QUESTION:A silicon diode is in series with 1k resistor and a forwardbiasing voltage supply of 10V. If rd is 10, what is the ancathode current and voltage?

a. 9.3mA, 0.7Vb. 9.3mA,0.79Vc. 9.21mA,0.7V

d. 9.21mA,0.79VANSWER: d. 9.21mA,0.79V

SOLUTION ( IF PROBLEM -SOLVING)IF=(10-0.7)/(10+1k)=9.21mAVF=0.7+10(9.21mA=0.79V

QUESTION:What is the wavelength of the light produced by an LED wienergy gap level of 1.43 eV?

a. 569nmb. 669nmc. 768nmd. 869nm

ANSWER: d. 869nm


=hc/Eg =(6.626x10-34Js*3x108m/s) /(1.43eV*1.6x10-19J/eV)

= 869nm

QUESTION:What is the bandgap energy for diamonds?

Choices:a. 2.5eVb.1.1eVc.5.6eVd. 0.1eV

ANSWER:a. 2.5eV

QUESTION:Charge carriers move in semiconductors via two mechanis

_____ and _______.


9/10

Choices:a. drift and diffusionb. drift and avalanchec. avalanche and diffusiond. none of the above

ANSWER:a. drift and diffusion

QUESTION:The diffusion current density is proportional to the _________ ofthe carrier concentration

Choices:a. gradientb. curl

c. divergenced. laplacian

ANSWER:a. gradient

QUESTION:The ___________ is the minimum energy required to dislodgean electron from its covalentbond.

Choices:a.barrier potentialb. bandgap energyc. potential energyd. diffusion energy

ANSWER:b. bandgap energy

QUESTION:Under a high reverse bias voltage, pn pn junctions break down,conducting a very high current.Depending on the structure and doping levels of the device,

____________ breakdown may occur.

Choices:a. Zenerb. Avalanchec. Driftd. answers a or b

ANSWER:d. answers a or b

QUESTION:The statement A voltage-dependent current source can form anamplifier along with a load resistor is

Choices:a. True b. Falsec. Cannot be determined d. Sometimes True

ANSWER: a. True

QUESTION:The ________________ of the bipolar transistor consists of anexponential voltage-dependentcurrent source tied between the collector and emitter, and adiode (accounting for the basecurrent) tied between the base and emitter.

Choices:a. r-paramter modelb. h-parameter modelc. small signal-modeld. large-signal model

ANSWER:d. large-signal model

QUESTION:MOSFETs operate in the ________ region if the drain voltage ismore than one threshold below the gate voltage

Choices:a. triodeb. diodec. negative resistanced. constant current

ANSWER:a. triode

QUESTION:A measure of the small-signal performance of voltage-dependent current sources is the _____________ defined as thechange in the output current divided by the change in the input

voltage.

Choices:a. impedanceb. conductancec. transconductanced. reluctance

ANSWER:c. transconductance

QUESTION:The impedance seen looking into the gate of a MOSFET is to ________

Choices:a. infinityb. r0

c. 1 / gmd. zero

ANSWER:a. infinity

QUESTION:The _______________ topology exhibits a nominal gain eto one plus the ratio oftwo resistors. The circuit also suffers from a gain error thainversely proportional to thegain of the op amp.

Choices:a. noninverting amplifierb. inverting amplifierc. summing amplifierd. voltage follower

ANSWER:a. noninverting amplifier

QUESTION:Placing a bipolar device around an op amp provides a

_____________function

Choices:a. linearb. parabolicc. exponentiald. logarithmic

ANSWER:d. logarithmic

QUESTION:Op amps suffer from various imperfections, including dc ofand input bias currents.These effects impact the performance of various circuits, mnotably,____________.

Choices:a. zero-level detectorb. summing amplifierc. differentiatorsd. integrators

ANSWER:d. integrators

QUESTION:Stacking a transistor atop another forms a _______ structresulting in a high output impedance.

Choices:a. darlingtonb. stack

c. cascaded. cascode

ANSWER:d. cascode

QUESTION:Bipolar differential pairs exhibit a ____________input/outcharacteristic. The tail current can be mostly steered to onwith a differential input of about 4Vt.

Choices:a. parabolicb. logarithmicc. hyperbolic tangentd. exponential


10/10

ANSWER:c. hyperbolic tangent

QUESTION:As the frequency of operation increases, capacitances exhibit a

______________, reducing the gain. The gain thus rolls off athigh signal frequencies.

Choices:a. same impedanceb. slightly higher impedancec. lower impedanced. significantly higher

ANSWER:

c. lower impedance

QUESTION:To obtain the frequency response, we must derive the

___________ of the circuit.

Choices:a. logarithmic behaviorb. roll-off ratec. gaind. transfer function

ANSWER:d. transfer function

QUESTION:A capacitance tied between the input and output of an inverting

amplifier appears at the input with a factor equal to one minusthe gain of the amplifier. This is called _______________.

Choices:a. Capacitance-gain effectb. Miller effectc. Thevenin effectd. Faraday effect

ANSWER:

b. Miller effect

QUESTION:The ________of a feedback system can, in principle, beobtained by breaking the loop, injecting a test signal, andcalculating the gain as the signal goes around the loop. Itdetermines many properties of feedback systems, e.g., gain,frequency response, and I/O impedances.

Choices:a. loop gainb. transfer functionc. negative feedbackd. signal flow

ANSWER:a. loop gain

QUESTION:To avoid oscillation, the gain crossover frequency must

__________the phase crossover frequency.

Choices:

a. fall belowb. rise abovec. be equald. a factor of

ANSWER:a. fall below

QUESTION:The crossover distortion resulting from the dead zone can bereduced by biasing the push-pull transistors for a smallquiescent current

Choices:a. Trueb. False

ANSWER:a. True

QUESTION:In low-distortion applications, the output stage may beembedded in a _________ to suppress the nonlinearity.

Choices:a. open loopb. positive feedback loopc.negative feedback loopd. none of the above

ANSWER:c.negative feedback loop

QUESTION:A push-pull stage operating at high temperatures may sufffrom _____________, whereby the elevated temperaturesthe output transistors to draw higher currents, which in tumakes them dissipate even more.

Choices:a. avalanche effectb. diffusion effectc. thermal runawayd. thermal breakover

ANSWER:c. thermal runaway

QUESTION:

The ___________ response provides a sharper transition tButterworth at the cost of someripple in the passband and stopbands. It contains n complpoles on an ellips

Choices:a. Thomasb. Buttordc. Ellipticd. Chebyshev

ANSWER:d. Chebyshev

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