QUESTION: A type of oscillator which uses an amplifier circuit that introduces 1800 phase shift Choices: a. RC Phase Shift Oscillator b. Wien Bridge Oscillator c. Hartley Oscillator d. Armstrong Oscillator Answer: A QUESTION: A type of Oscillator that is very commonly used as local oscillator in superheterodyne radio receiver Choices: a. RC Phase Shift Oscillator b. Colpitt‟s Oscillator c. Clapp Oscillator d. Wien Bridge Oscillator ANSWER: A. Colpitt‟s Oscillator QUESTION: The measure of how “pure” or “real” an inductor is. The higher its value in an inductor, the fewer losses there are. Choices: a. Q-factor b. Beta Factor c. Alpha Factor d. K-factor ANSWER: a. Q-factor QUESTION: This can be defined as the ratio of output d.c. power available at the load to the power rating (Volt Ampere) of the transformer used in the rectifier circuit Choices: a. Transformer Utilization Factor b. Transformer Form Factor c. Transformer Load Voltage Factor d. Transformer Working Factor ANSWER: a. Transformer Utilization Factor QUESTION: A type of flip-flop in which the data are entered and appear on the output on the same clock edge. Choices: a. Set Reset Flip flop b. Edge Triggered Flip flop c. JK Flip flop d. D Flip flop ANSWER: b. Edge Triggered Flip flop QUESTION: If the feedback signal (voltage or current) is applied in such a way that it is in phase with the input signal and thus increases. It is also known as regenerative feedback feedback or direct feedback Choices: a. Positive Feedback b. Negative Feedback c. Stabilized Feedback d. Impedance Feedback ANSWER: a. Positive Feedback QUESTION: Refers to the process of shrinking the size and power dissipation of electronic circuits. It also involves surface mount technology Choices: a. Gull wing b. Microminiaturization c. Floating Point d. Synchronous Deviation ANSWER: a. Microminiaturization
QUESTION: A non-volatile read/write random access semiconductor memory in which data are stored as charge on the floating gate of a certain type of FET Choices: a. PROM b. Hard Disk c. Flash Memory d. RAM ANSWER: a. Flash Memory QUESTION: It is a channel model in which the input and output alphabets x and y are discrete sets and the channel is memoryless Choices: a. The Discrete Memory Channel b. The Discrete channel c. The Discrete Memoryless Chanel d. None of the above ANSWER: C. The Discrete Memoryless Chanel QUESTION: It is a diagnostic application or device that a network administrator can purchase and install on a network workstations or attach to the network media to monitor and capture dat packets for subsequent analysis.. Choices: a. Sniffer b. Splatter c. Clipper d. Clamper ANSWER: a. Sniffer QUESTION: _______________ _______________ is a secret key encryption technology technology that is used in client/server environments for secure authentication between computers Choices: a.Kepberos b. Kerberos c. Kesberos d. None of the above ANSWER: b. Kerberos QUESTION: What is the circuit which has a purpose to quiet a receiver in the absence of a received signal? Choices: a. Squilch circuit b.Squealch circuit c. Squelch circuit d. Squeltch circuit ANSWER: c. Squelch circuit QUESTION: What is network node dedicated to interfacing between the network and one or more pr inters? Choices: a. Print server b. Lay-out Server c. Tune server d. All of the above ANSWER: a. Print server QUESTION: What is formed on the screen of cathode ray oscilloscope when two sine wave voltages are simultaneously applied to the two sets of deflection plates? Choices: a. Lizzajous pattern b. Lisajous pattern c .Lissajous pattern d. Lizajous pattern ANSWER: C. Lissajous pattern
QUESTION: A type of circuit that consists of two matching transistors with the collector of one connected to the bases of both, thus producing the same collector current in each transistor. Choices: a. current b. current c. Darlington d. equivalent limiting mirror pair circuit ANSWER: B. current mirror QUESTION: Determine the cut-off frequency of an op-amp having unity bandwidth 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 di stortion in the output cause by the transition of state of transistors from cut-off state to the on state is called ____. Choices: a. harmonic b. crossover c. clipping d. aliasing distortion distortion 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 SOLUTION ( IF PROBLEM -SOLVING)
⁄ ⁄
QUESTION: A certain voltage regulator has a 12 V output when there is no load. When there is a full-load current of 10 mA, the output voltage is 11.9 V. What is the voltage regulation? Express in %/mA. Choices: a. 0.00084 b. 0. 0084 c. 0.084 d. 0.84 %/mA %/mA %/mA %/mA ANSWER: C. 0.084 %/mA SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: A class C amplifier is driven by a 200 kHz signal. The transistor is on for 1us, and the amplifier is operating over 100 percent of its load line. If IC(sat) = 100 mA and VCE(sat) = 0.2 V, what is the average power dissipation of the transistor? Choices: a. 20 mW b. 2 mW c. 40 mW d. 4 mW ANSWER: D. 4 mW SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: The nominal output voltage of a certain regulator is 8 V. The output changes 2 mV when the input voltage foes from 12 V to 18 V. Determine the line regulation and express it in units of %/V. Choices: a. 0.004167 b. 0.033333 c. 0.155556 d. 0.266667 %/V %/V %/V %/V ANSWER: A. 0.004167 %/V SOLUTION ( IF PROBLEM -SOLVING)
⁄ ⁄
QUESTION: What is VOUT for a transistor log amplifier with VIN = 3 V and R1 = 68 kΩ? Assume IEBO = 40 nA. Choices: a. 1.751 mV b. -1.751 mV c. 175.1 mV d. -175.1 mV ANSWER: D. -175.1 mV SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: In a self-biased JFET, the gate is at Choices: a. a positive b. 0 V c. a negative d. ground voltage voltage ANSWER: B. 0 V QUESTION: It is the time taken by a diode to operate in the reverse condition from forward conduction. Choices: a. reverse b. transition c. storage d. response recovery time time time time ANSWER: A. reverse recovery time QUESTION: The MOSFET in a certain single-stage common-source amplifier has a range of forward transconductance values from 2.5 mS to 7.5 mS. If the amplifier is capacitively coupled to a variable load that ranges from 4 kΩ to 10 kΩ and the dc drain resistance is 1.0kΩ, Determine the maximum voltage gain. Choices: a. 2.0 b. 3.53 c. 4.67 d. 6.82 ANSWER: D. 6.82
SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: This diode provides fast voltage transitions by the very sudden disappearance of the charge carriers. After a forward current has been passing in the diode and the current is interrupted, the reverse conduction will cease very abruptly. Choices: a. Schottky b. Stepc. Tunnel d. Point diode recovery diode contact diode diode ANSWER: B. Step-recovery diode QUESTION: What theory states that "any resistance R in a branch of a network in which a current I is flowing can be replaced by a voltage equal to IR"? Choices: a. Source b. c. d. Transformation Norton's Superposition Compensation Theorem Theorem Theorem ANSWER: D. Compensation Theorem QUESTION: The resonant circuit of a tuned-collector transistor oscillator has a resonant frequency of 5 MHz. If the value of capacitance is increased 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 SOLUTION ( IF PROBLEM -SOLVING)
√ )√ √ √ √ (√
QUESTION: For a silicon diode, calculate the current at room temperature if the forward voltage, Vf = 0.3 V and the reverse saturation current 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
SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: A BUZ73L MOSFET has an „on‟ resistance of 0.4 OHMS and is rated at 7 A. If the supply voltage is 9 V, what is the minimum resistance of a device in series that it can safely switch? Choices: a. 1.286 ohms b. 0.886 ohms c. 0.486 ohms d. 0.4 ohms ANSWER: b. 0.886 ohms SOLUTION ( IF PROBLEM -SOLVING) 9=7(0.4 + R) R = 0.886 ohms QUESTION: What is the minimum contact rating for a relay required to switch 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 increases by 2 V, the drain current increases by 1.7 A. What is the transconductance of the MOSFET? Choices: a. 3.4 mho b. 1.31 mho c. 0.85 Siemens d. 0.59 mho 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 supply. It then holds 1.5 coulombs of charge. What is its capacitance? Choices: a. 6 Farad b. 4 Farad c. 0.5 Farad d. 0.25 Farad 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= 1.5 μF . What is the length of the output pulse? Choices: a. 2.079milliseconds b. 2.310ms c. 2.970 ms d. 3.630 ms 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=150 nF. What is the frequency and the mark-space ratio of the output signal? Choices: a. 406.78Hz b. 571.43Hz c. 273.81Hz d. 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 impedance of 2.2 kOHMS? Choices: a. 22,727.27 Hz b. 1,033.06 Hz c. 657.67 Hz d. 328.83 Hz 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 μF. What is the impedance of the capacitor at 10 kHz? Choices: a.7.23 ohms b. 21.28 ohms c. 213.64 ohms d. 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 in dB at cut-off fr equency? Choices: a. 7.78 dB b. 4.78dB c. 1.78 dB d. 0.707dB ANSWER: b. 4.78dB
SOLUTION ( IF PROBLEM -SOLVING) Ap(cutoff) = Ap *0.5 Ap(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 the gain at critical frequency? Choices: a.11.78 b. 8.33 c. 5.89 d. 4.17 ANSWER: c. 5.89 SOLUTION ( IF PROBLEM -SOLVING) Av(cutoff) = Av* 0.707 = 500mV/60mV*0.707 = 5.89 QUESTION: The current in a coil begins to fall at the rate of 6 A/s. If L = 840 mH, 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 the input r esistance? 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 = 1 kohms, 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 is increased by 15 μA, the collector current increase s 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 / 15uA ic = 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 gainbandwidth product of the op -amp. Choices: a. 6 MHz b. 3 MHz c. 2 MHz d. 1.5 MHz
Choices: a. 822.2 kohms kohms ANSWER: c. 2.2 kohms
b. 820 kohms
c. 2.2 kohms
d. 1.1
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 frequency ANSWER: d. transition frequency
c. 10 MHz
d. transition
QUESTION: The input resistor of a non-inverting op amp is 39 kohms and the feedback resistor is 1.2 Mohms. The output voltage is – 0.5 V. The input voltage is: Choices: a. – 15.74mV b. +15.74mV c. – 16.25mV d. +16.25mV ANSWER: a. – 15.74mV SOLUTION ( IF PROBLEM -SOLVING) Av=(1+ RF/RA)=Vo/Vi = (1+1M/39k)= - 0.5V / Vi Vi = – 15.74mV QUESTION: If the input voltage is constant at 20 mV, R is 10 kOHMS and C is 470 nF, what is output voltage of an integrator after 25 ms? Choices: a. - 3.76 mV b. – 9.4 mV c. - 14.14mV d. - 106.38 mV ANSWER: d. - 106.38 mV SOLUTION ( IF PROBLEM -SOLVING) Vout(@25ms) = -Vin * t/(RC)= -20mV(25msec)/(10k*470n) = 106.38 mV QUESTION: At the cut-off point of a lowpass filter the phase change is: Choices: a. +90 degree degree ANSWER: c. – 45 degree
b. 0 degree
c. – 45 degree
d. – 90
QUESTION: An active bandpass filter is built fr om a lowpass filter cascaded with a highpass filter. It has a lower cutoff frequency of 200 Hz, and a bandwidth of 800 Hz. The cutoff points of its two filters are: 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
ANSWER: c. 2 MHz
QUESTION: The metal tag of a power transistor operating at 2.2 W is at 90 degree Celsius. It is bolted to a heat sink and the ambient temperature (inside the circuit enclosure) is 35 degree Celsius. What 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 C/W
SOLUTION ( IF PROBLEM -SOLVING) GBP=AvBw=Avfc=20(100kHz)=10(200kHz)=5(400kHz)=2 MHz
ANSWER: b. 25 C/W SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: Calculate the best value for RB(compensating resistor) for an inverting amplifier in which RA=2.2 kohms(input component) and RF=820 kohms(feedback component).
Thermal resistance = (90-35)/2.2 = 25 C/W QUESTION: A snubber network is used to reduce___.
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 might be____. 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. The input 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=15kohms R1=8RF=2R2=7.5kohms R2=4RF=2R3=3.75kohms R3=2RF QUESTION: A phenomenon that occurs for large reverse voltages across a pn junction where the free electrons are accelerated to such high speeds that they can dislodge valence electrons. a. Piezoelectric effect b. Zener Effect c. Recombination d. Avalanche effect ANSWER: d. Avalanche effect QUESTION: A graph showing the gain or phase performance of an electronic circuit at various frequencies. a. Ogive graph b. Bode plot c. Gain-frequency curve d. Performance graph ANSWER: b. Bode plot QUESTION: What do you call the ohmic resistance of the semiconductor? a. Dynamic r esistance b. Static resistance c. Bulk resistance d. Semiconductor resistance ANSWER: c. Bulk resistance QUESTION: The metaphor used to describe the action of an SCR when it is used to protect a load against supply. a. Surge b. Limiter c. Breaker d. Crowbar ANSWER: d. Crowbar QUESTION: A value that tells you how much to reduce the power rating for each degree above the reference temperature given on the data sheet. a. Reduction factor b. Derating factor c. Temperature coefficient d. Attenuation ANSWER: b. Derating factor
QUESTION: It is the process of adding impurity element to an intrinsic semiconductor to change its conductivity. a. Impurification b. Crystallization c. Recombination d. Doping ANSWER: d. Doping QUESTION: A condition where the transistor is operating at the upper end of the load line with a base current that is one-tenth of the collector current. a. Full saturation b. Hard saturation c. Mid saturation d. Avalanche ANSWER: b. Hard saturation QUESTION: A connection of two transistors connected with positive feedback to simulate the action of a thyristor. a. Complementary b. Latch c. Push pull d. Switch ANSWER: b. Latch QUESTION: It refers to the average amount of time between the creation and recombination of a free electron and a hole. a. Recombination time b. Delay time c. Conduction time d. Life time ANSWER: d. Life time QUESTION: A filter that blocks a signal with at most one fr equency. a. Brick wall filter b. Cauer filter c. Notch filter d. Butterworth filter ANSWER: c. Notch filter QUESTION: A term use to describe the death of amplification. a. Oscillation b. Attenuation c. Degradation d. Hysteresis ANSWER: a. Oscillation QUESTION: The voltage that provides the border between the ohmic region and the constant current region of a depletion-mode device when the gate to source voltage is zero. a. Threshold voltage b. Peak point voltage c. Valley point voltage d. Pinch off voltage ANSWER: d. Pinch off voltage QUESTION: A basic circuit that a designer can modify to get more advanced circuits. a. Model circuit b. Miniature circuit c. Prototype d. Hybrid ANSWER: c. Prototype QUESTION: It is a comparator with hysteresis. a. Schmitt trigger b. Hysteresis circuit c. Trigger-comparator d. Latch circuit ANSWER: a. Schmitt trigger
QUESTION: Which of the following special purpose diode doesn‟t have depletion layer? a. Tunnel diode b. Schottky diode c. Varactor diode d. Zener diode ANSWER: b. Schottky diode QUESTION: It is define as a large initial current that flows through the diode of a rectifier. a. Bleeder current b. Surge current c. Transient current d. Saturated current ANSWER: b. Surge current QUESTION: It is defined as a four-layer semiconductor device that acts as a latch. a. Thyrector b. Transistor c. Transformer d. Thyristor ANSWER: d. Thyristor QUESTION: It is the value of the input voltage that switches the output of a comparator. a. Trigger b. Trip point c. Latch d. Knee ANSWER: b. Trip point QUESTION: It is a device a. b. c. d. ANSWER:
that acts like two back-to-back-zener diodes. Varistor Varactor Complementary zener Zener latch
a. Varistor
QUESTION: What do you call a thin slice of crystal used as a chassis for integrated components. a. Substrate b. Base c. Wafer d. Impurity ANSWER: c. Wafer QUESTION: What is the other term for zener effect? a. Avalanche effect b. Piezoelectric effect c. High field emission d. Breakdown effect ANSWER: c. High field emission QUESTION: Calculate the efficiency of a transformer-coupled class A amplifier for a supply of 12 V and outputs of 6V. a. 50% b. 25% c. 12.5% d. 10% ANSWER:
QUESTION: For a class B amplifier providing a 20-V peak to a 16-Ω load (speaker) and a power supply of Vcc = 30 V, determine the circuit efficiency. a. 45.2% b. 66.67% c. 78.5% d. 52.3% ANSWER:
SOLUTION ( IF PROBLEM -SOLVING)
For resulting efficiency of QUESTION: For a class B amplifier using a supply of Vcc = 30 V and driving a load of 16Ω, determine the maximum output power. a. 28.13W b. 35.81W c. 41.23W d. 54.91W ANSWER:
Maximum
QUESTION: For a class B amplifier using a supply of Vcc = 30 V and driving a load of 16Ω, determine the transistor dissipation a. 3.7W b. 4.7W c. 5.7W d. 6.7W ANSWER:
c. 5.7W
SOLUTION ( IF PROBLEM -SOLVING)
Maximum
*+
QUESTION: Calculate the efficiency of a class B amplifier for a supply of Vcc = 24 V with peak output voltages of VL (p) = 22 V. a. ANSWER:
62%
b. 68%
c. 72%
d. 78%
c. 72%
SOLUTION ( IF PROBLEM -SOLVING)
a.
QUESTION: Calculate the total harmonic distortion for the following amplitude components: fundamental amplitude of 2.5 V, second harmonic amplitude of 0.25 V, third harmonic amplitude of 0.1 V, and fourth harmonic amplitude of 0.05 V. a. 11% b. 12% c. 13% d. 14% ANSWER:
a. 11%
SOLUTION ( IF PROBLEM -SOLVING)
SOLUTION ( IF PROBLEM -SOLVING)
Resulting in
b.35.81W
SOLUTION ( IF PROBLEM -SOLVING)
c. 12.5%
d. 52.3%
QUESTION: Determine what maximum dissipation will be allowed for an 80 W silicon transistor (rated at25 ) if the reading is required above 25 by a derating factor of 0.5W/ at case temperature of 125 . a. 25W b. 30W c. 35W d. 40W
℃
℃℃
ANSWER:
℃
a.
Both 32.5nA b. Both 27.5nA 32.5nA; 27.5nA ANSWER: d. 32.5nA; 27.5nA
c. 27.5nA; 32.5nA
d.
SOLUTION ( IF PROBLEM -SOLVING)
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 maximum power can be dissipated if the ambient temperature is a. 61.5W b. 71.5W c. 81.5W d. 91.5W
QUESTION: Determine the cutoff frequency of an op-amp having specified values B1 = 1 MHz and AVD = 200 V/mV.
ANSWER:
ANSWER:
℃ ℃ ℃
℃ ℃ ℃
a. 61.5W
SOLUTION ( IF PROBLEM -SOLVING)
a.
4Hz
b. 5Hz
c. 1kHz
d. 1MHz
b. 5Hz
SOLUTION ( IF PROBLEM -SOLVING)
℃℃ ℃℃℃ QUESTION: A dc voltage supply provides 50 V when the output is unloaded. When connected to a load, the output drops to 56 V. Calculate the value of voltage regulation. a. 4.1% b. 7.1% c. 5.7% d. 10.7% ANSWER:
b. 7.1%
SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: For an op-amp having a slew rate of SR = 2V/µs, what is the maximum closed loop voltage gain that can be used when the input signal varies by 0.5 V in 10 µs? a. 10 b. 20 c. 30 d. 40 ANSWER: d. 40 SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: Calculate the ripple voltage of a full-wave r ectifier with a 100-μF filter capacitor connected to a load drawing to a load drawing 50 mA a. 1.2V b. 2.5V c. 2.7V d. 3.1V ANSWER:
a. 1.2V
SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: Calculate the filter dc Voltage of a f ull-wave rectifier with a 100μF filter capacitor connected to a load drawing to a load drawing 50 mA if the peak rectifier voltage is 30 V. a. 25.4V b. 26.1V c. 27.9V d. 28.6V ANSWER:
QUESTION: Determine the output voltage of an op-amp for input voltages of Vi1 = 150 µV and Vi2 = 140 µV. The amplifier has a differential gain 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
SOLUTION ( IF PROBLEM -SOLVING)
c. 27.9V
SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: Calculate the ripple of a capacitor filter for a peak rectified voltage of 30 V, capacitor C= 100μF, and a load current of 50 mA.
a. ANSWER
3.7%
b. 4.3%
c. 5.1%
d. 6.9%
b. 4.3%
SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: Calculate the input bias currents at the non-inverting and inverting terminal respectively of an op=amp having specified values of IIO = 5nA and IIB = 30 nA.
QUESTION: If an amplifier with gain of -1000 and feedback of β=-0.1 has a gain change of 20% due to temperature; calculate the change in gain of the feedback amplifier a. 10% b. 0.2% c. 20% d. 1% ANSWER b. 0.2% SOLUTION ( IF PROBLEM -SOLVING)
||
(20%) = 0.2%
QUESTION: A transistor has a collector current of 10mA and a base current of 40uA. What is the current gain of the transistor a. 20 b. 30 c. 40 d. 50 ANSWER: d. 50 SOLUTION ( IF PROBLEM -SOLVING) β=10mA/40uA=50 QUESTION: A 2N3904 has VCE=10V and IC=20mA. What is the power dissipation? a. 0W b. 100mW c. 200mW d. 2N3904 is limited to 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 to 30V. If the regulated output voltage is 12V and the load resistance varies from 140Ω to 10kΩ, what is the maximum allowable series resistance? a. 140Ω b. 76.4 Ω c. 280 Ω d. 117 Ω ANSWER: d. 117 Ω
QUESTION: It is sometimes called hot-carrier diode. a. Shockley diode b. Schottky diode c. Gunn Diode d. Tunnel diode ANSWER: b. Schottky diode
SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: A 2N5668 has VGS(off)=-4V and IDSS=5mA. What are the gate voltage and drain current at the half cutoff point?
c. -4V; 5mA
ANSWER:
b. 26mV
SOLUTION ( IF PROBLEM -SOLVING) Vt =kT/q=(1.38x10-23J/K)(273+17)/1.6x10-19C = 26mV QUESTION: What is the knee voltage of a silicon diode at 75°C? a. ANSWER:
0.7V
b. 2.1V
c. 0.58V
d. 0V
c. 0.58V
SOLUTION ( IF PROBLEM -SOLVING) (75-25)°C*2.5mV/°C = 0.125V
0.32uA
b. 50nA
c. 10nA
d. 0A
ANSWER: a. 0.32uA
ANSWER b. 410 Ω
b. -2V; 1.25mA
QUESTION: Determine the thermal voltage of a diode at 27°C (common temperatures for components in an enclosed operating system) a. 20mV b. 26mV c. 30mV d. 1V
a.
QUESTION: A zener regulator has an input voltage ranging fro m 15 to 20V and a load current ranging from 5 to 20mA. If the zener voltage is 6.8V, what is the maximum allowable series resistance? a. 750Ω b. 410 Ω c. 1000Ω d. 2000 Ω
-1V; 1mA
Transition time Time constant Rise time Storage time Storage time
New Vknee = 0.7-0.125 = 0.575V QUESTION: At 20°C, the reverse saturation current of a silicon diode is 10nA, what is its value when the temperature increases to 100°C?
SOLUTION ( IF PROBLEM -SOLVING)
a.
a. b. c. d. ANSWER: d.
d. 0; 0
ANSWER: b. -2V; 1.25mA SOLUTION ( IF PROBLEM -SOLVING)
QUESTION: A network that employ diodes to remove away a portion of an input signal without distorting the remaining part of the applied waveform a. Clamper b. Rectifier c. Regulator d. Clipper ANSWER: d. clipper QUESTION: The time required for the minority carriers to return to the majority carrier state in the opposite material.
SOLUTION ( IF PROBLEM -SOLVING) 100 °C / 20°C = 5 New Ireverse = 2 5(10nA)= 0.32uA QUESTION: A silicon diode is in series with 1kΩ resistor and a forward biasing voltage supply of 10V. If r‟d is 10Ω, what is the anode to cathode current and voltage? a. 9.3mA, 0.7V b. 9.3mA,0.79V c. 9.21mA,0.7V d. 9.21mA,0.79V ANSWER: d. 9.21mA,0.79V SOLUTION ( IF PROBLEM -SOLVING) IF=(10-0.7)/(10+1k)=9.21mA VF=0.7+10(9.21mA=0.79V QUESTION: What is the wavelength of the light produced by an LED with an energy gap level of 1.43 eV? a. 569nm b. 669nm c. 768nm d. 869nm ANSWER: d. 869nm SOLUTION ( IF PROBLEM -SOLVING) λ=hc/Eg =(6.626x10-34Js*3x108m/s) /(1.43eV*1.6x1019J/eV) = 869nm QUESTION: What is the bandgap energy for diamonds? Choices: a. 2.5eV b.1.1eV c.5.6eV d. 0.1eV ANSWER: a. 2.5eV QUESTION: Charge carriers move in semiconductors via two mechanisms: _____ and _______.
Choices: a. drift and diffusion b. drift and avalanche c. avalanche and diffusion d. none of the above ANSWER: a. drift and diffusion QUESTION: The diffusion current density is proportional to the _________ of the carrier concentration Choices: a. gradient b. curl c. divergence d. laplacian ANSWER: a. gradient QUESTION: The ___________ is the minimum energy required to dislodge an electron from its covalent bond. Choices: a.barrier potential b. bandgap energy c. potential energy d. 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. Zener b. Avalanche c. Drift d. answers a or b ANSWER: d. answers a or b QUESTION: The statement” A voltage -dependent current source can form an amplifier along with a load resistor” is Choices: a. True b. False c. Cannot be determined d. Sometimes True ANSWER: a. True QUESTION: The ________________ of the bipolar transistor consists of an exponential voltage-dependent current source tied between the collector and emitter, and a diode (accounting for the base current) tied between the base and emitter. Choices: a. r-paramter model b. h-parameter model c. small signal-model d. large-signal model ANSWER: d. large-signal model QUESTION: MOSFETs operate in the ________ region if the drain voltage is more than one threshold below the gate voltage Choices: a. triode b. diode c. negative resistance d. constant current ANSWER: a. triode QUESTION: A measure of the small-signal performance of voltagedependent current sources is the _____________ defined as the change in the output current divided by the change in the input voltage.
Choices: a. impedance b. conductance c. transconductance d. reluctance ANSWER: c. transconductance QUESTION: The impedance seen looking into the gate of a MOSFET is equal to ________ Choices: a. infinity b. r0 c. 1 / gm d. zero ANSWER: a. infinity QUESTION: The _______________ topology exhibits a nominal gain equal to one plus the ratio of two resistors. The circuit also suffers from a gain error that is inversely proportional to the gain of the op amp. Choices: a. noninverting amplifier b. inverting amplifier c. summing amplifier d. voltage follower ANSWER: a. noninverting amplifier QUESTION: Placing a bipolar device around an op amp provides a _____________function Choices: a. linear b. parabolic c. exponential d. logarithmic ANSWER: d. logarithmic QUESTION: Op amps suffer from various imperfections, including dc offsets and input bias currents. These effects impact the performance of various circuits, most notably,____________. Choices: a. zero-level detector b. summing amplifier c. differentiators d. integrators ANSWER: d. integrators QUESTION: Stacking a transistor atop another forms a _______ structure, resulting in a high output impedance. Choices: a. darlington b. stack c. cascade d. cascode ANSWER: d. cascode QUESTION: Bipolar differential pairs exhibit a ____________input/output characteristic. The tail current can be mostly steered to one side with a differential input of about 4Vt. Choices: a. parabolic b. logarithmic c. hyperbolic tangent d. exponential
ANSWER: c. hyperbolic tangent QUESTION: As the frequency of operation increases, capacitances exhibit a ______________, reducing the gain. The gain thus rolls off at high signal frequencies. Choices: a. same impedance b. slightly higher impedance c. lower impedance d. significantly higher ANSWER: c. lower impedance QUESTION: To obtain the frequency response, we must derive the ___________ of the circuit. Choices: a. logarithmic behavior b. roll-off rate c. gain d. 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 minus the gain of the amplifier. This is called _______________. Choices: a. Capacitance-gain effect b. Miller effect c. Thevenin effect d. Faraday effect ANSWER: b. Miller effect QUESTION: The ________of a feedback system can, in principle, be obtained by breaking the loop, injecting a test signal, and calculating the gain as the signal goes around the loop. It determines many properties of feedback systems, e.g., gain, frequency response, and I/O impedances. Choices: a. loop gain b. transfer function c. negative feedback d. signal flow ANSWER: a. loop gain QUESTION: To avoid oscillation, the gain crossover fr equency must __________the phase crossover frequency. Choices: a. fall below b. rise above c. be equal d. a factor of ANSWER: a. fall below QUESTION: The crossover distortion resulting from the dead zone can be reduced by biasing the push-pull transistors for a small quiescent current Choices: a. True b. False
ANSWER: a. True QUESTION: In low-distortion applications, the output stage may be embedded in a _________ to suppress the nonlinearity. Choices: a. open loop b. positive feedback loop c.negative feedback loop d. none of the above ANSWER: c.negative feedback loop QUESTION: A push-pull stage operating at high temperatures may suffer from _____________, whereby the elevated temperatures allow the output transistors to draw higher currents, which in turn makes them dissipate even more. Choices: a. avalanche effect b. diffusion effect c. thermal runaway d. thermal breakover ANSWER: c. thermal runaway QUESTION: The ___________ response provides a sharper transition than Butterworth at the cost of some ripple in the passband and stopbands. It contains n complex poles on an ellips Choices: a. Thomas b. Buttord c. Elliptic d. Chebyshev ANSWER: d. Chebyshev