1. An op-amp comparator circuit uses which of the following? a. positive feedback b. negative feedback c. active feedback d. no feedback 2. Which of the following refers to the voltage gain of an op-amp that has no negative feedback? a. unity gain b. open-loop gain c. closed-loop gain d. positive gain 3. A simple op-amp circuit wherein the output is directly tied to the inverting input is known as what? a. voltage follower b. inverting amplifier c. non-inverting amplifier d. comparator 4. The parameter that is a measure of the maximum rate of change of an op amp output in response to a large step input is known as what? a. ramp rate b. slew rate c. step rate d. response rate 5. The feedback path for the simplest op-amp differentiator uses which of the following? a. resistor b. capacitor c. inductor d. diode 6. What is the main advantage of a shunt regulator over a series regulator? a. higher efficiency b. lower cost c. inherently limits current d. none of the above 7. Which of the following describes the behavior of the voltage across the capacitor of an integrator whose input voltage is constant? a. constant b. linear c. exponential d. pulsating 8. Which of the following describes the behavior of the current across the capacitor of an integrator whose input voltage is constant? a. constant b. linear c. exponential d. pulsating 9. An oscillating circuit with unity gain has which of the following around its feedback loop? a. no feedback b. integrator c. zero phase shift d. changing phase shift 10. Which of the following describes the unity gain frequency of an op amp? a. frequency where b. highest useable voltage gain = 1 frequency c. numerically equal to the d. all of the above gain-bandwidth product See the answers below... Answers to the questions: 1) d. no feedback 3) a. voltage follower 5) a. resistor 7) b. linear 9) c. zero phase shift 2) b. open-loop gain 4) b. slew rate 6) c. inherently limits current 8) a. constant 10) d. all of the above OP AMP - part 1 The OPAMP related objective questions are given in this post with answers. 1. A non inverting closed loop op amp circuit generally has a gain factor A. Less than one B. Greater than one C. Of zero D. Equal to one Ans: B. For non inverting amplifier the gain is A = [1 + (Rf/Rin)]. So it will be always more than one 2. If ground is applied to the (+) terminal of an inverting op-amp, the (–) terminal will A. Not need an input resistor B. Be virtual ground C. Have high reverse current D. Not invert the signal Ans: B. Other options are not suitable. Please refer the Goodrich Interview Post for understanding inverting amplifier and virtual ground. 3. The closed-loop voltage gain of an inverting amplifier equal to A. The ratio of the input resistance to feedback resistance B. The open-loop voltage gain C. The feedback resistance divided by the input resistance D. The input resistance Ans: C 4. When a number of stages are connected in parallel, the overall gain is the product of the individual stage gains A. True B. False Ans: B 5. An ideal OP-AMP is an ideal a) Current controlled Current source b) Current controlled voltage source c) Voltage controlled voltage source d) voltage controlled current source Ans: B. The ideal Opamp output voltage is maintained constant. It is controlled by input current. 6. The ideal OP-AMP has the following characteristics. a) Ri=∞ ,A=∞ ,R0=0 b) Ri=0 ,A=∞ ,R0=0 c) Ri=∞ ,A=∞ ,R0=∞ d) Ri=0 ,A=∞ ,R0=∞ Ans: A. Please refer the golden rules of Opamp. 7.Calculate the cutoff frequency of a first-order low-pass filter for R1 = 2.5kΩ and C1 = 0.05μF A. 1.273kHz B. 12.73kHz C. 127.3 kHz D. 127.3 Hz Ans: A. Hint: low pass filter cut off frequency f = 1/(2πRC) 8. How many op-amps are required to implement this equation A. 2 B. 3 C. 4 D. 1 Ans:B. The output voltage of inverting amplifier is Vout = (-Rf/Rin)Vin. By keeping 3 inverting amplifier, we can get this equation. 9. How many op-amps are required to implement this equation Vo = V1 A.4 B.3 C.2 D.1 Ans: D. The voltage follower which has one opamp has the output of Vo = Vin 10. An OPAMP has a slew rate of 5 V/μ S .The largest sine wave O/P voltage possible at a frequency of 1 MHZ is 10 volts 5 volts 5/ volts 5/2 volts Ans: D Hint: Slew rate is defined as the max. rate of change of output voltage. Its unit is V/μS. Time period = 1/f = 1/1MHz = 1μS V= Vm. sin(ωt) = Vm. sin(2πf.t) slew rate = dV/dt = d(Vm. sin(2πf.t)/ dt=Vm. 2πf. cost A. B. C. D. Read more: http://electricalobjectivequestion.blogspot.com/2012/08/op-amp-part1.html#ixzz2LRLagMyC Op-Amp Objective Questions: Part - 2 [1] Which of the following amplifier is used in a digital to analog converter? a. non inverter b. voltage follower c. summer d. difference amplifier Ans: C [2] Differential amplifiers are used in a. instrumentation amplifiers b. voltage followers c. voltage regulators d. buffers Ans: A [3] For an ideal op-amp, which of the following is true? a. The differential voltage across the input terminals is zero b. The current into the input terminals is zero c. The current from output terminal is zero d. The output resistance is zero Ans: C [4] The two input terminals of an opamp are labeled as a. High and low b. Positive and negative c. Inverting and non inverting d. Differential ans non differential Ans: C [5] When a step-input is given to an op-amp integrator, the output will be a. a ramp. b. a sinusoidal wave. c. a rectangular wave. d. a triangular wave with dc bias. Ans: A [6] For an op-amp having differential gain Av and common-mode gain Ac the CMRR is given by a. Av + Ac b. Av / Ac c. 1 + [Av / Ac] d. Ac / Av Ans: B [7] Hysteresis is desirable in Schmitt-trigger, because a. energy is to be stored/discharged in parasitic capacitances. b. effects of temperature would be compensated. c. devices in the circuit should be allowed time for saturation and desaturation. d. it would prevent noise from causing false triggering. Ans: C Circuit for questions 8 & 9 [8] The output voltage Vo of the above circuit is a. -6V b. -5V c. -1.2V d. -0.2V Ans: B [9] In the above circuit the current ix is a. 0.6A b. 0.5A c. 0.2A d. 1/12A Ans: B [10] Op-amp circuits may be cascaded without changing their input output relationships a. True b. False Ans: A Read more: http://electricalobjectivequestion.blogspot.com/2012/09/op-amp-objectivespart-2.html#ixzz2LRKybwYL Basic Electronics Objective Questions: Part - 1 [1] Removing bypass capacitor across the emitter leg resistor in a CE amplifier causes a. increase in current gain b. decrease in current gain c. increase in voltage gain d. decrease in voltage gain Ans: D [2] The minimum number of flip-flops required to construct a mod-75 counter is a. 5 b. 6 c. 7 d. 8 Ans: C [3] The important characteristic of emitter-follower is a. High input impedance and high output impedance b. High input impedance and low output impedance c. Low input impedance and low output impedance d. Low input impedance and high output impedance Ans: B [4] When an amplifier is provided with current series feedback, its a. Input impedance increases and output impedance decreases b. Input and output impedance both decrease c. Input impedance decreases and output impedance increases d. Input and output impedance both increase Ans: D [5] The frequency of oscillation of a tunnel-collector oscillator having L= 30μH and C = 300pf is nearby a. 267 kHz b. 1677 kHz c. 1.68 kHz d. 2.67 kHz Ans: B fo = 1/[2(pi)*square root(LC)] [6] The control terminal (pin 5) of 555 timer IC is normally connected to ground through a capacitor (0.01μF). This is to a. Protect the IC from inadvertent application of high voltage b. Prevent false triggering by noise coupled onto the pin c. Convert the trigger input to sharp pulse by differentiation d. Suppress any negative triggering pulse Ans: B [7] The fan out of a MOS logic gate is higher than that of TTL gates because of its a. Low input impedance b. high output impedance c. Low output impedance d. High input impedance Ans: D [8] The common collector amplifier is also known as a. Collector follower b. Base follower c. Emitter follower d. Source follower Ans: C [9] In class-A amplifier, the output current flows for a. A part of the cycle or the input signal b. The full cycle of the input signal c. Half the cycle of the input signal d. 3/4th of the cycle of the input signal Ans: B [10] In an amplifier with negative feedback a. Only the gain of the amplifier is affected b. Only the gain and bandwidth of the amplifier are affected c. Only the input and output impedance are affected d. All of the four parameters mentioned above would be affected Ans: D Read more: http://electricalobjectivequestion.blogspot.com/2012/09/basic-electronicsobjective-questions.html#ixzz2LRMzDrDT Basic Electronics Objectives Part-2 [1] Wien bridge oscillator can typically generate frequencies in the range of a. 1kHz - 1 Mhz b. 1 Mhz - 10MHz c. 10MHz - 100MHz d. 100MHz - 150MHz Ans: A [2] A differential amplifier, amplifies a. and mathematically differentiates the average of the voltages on the two input lines b. and differentiates the input waveform on one line when the other line is grounded c. the difference of voltages between the two input lines d. and differentiates the sum of the two input waveform Ans: C [3] The type of power amplifier which exhibits crossover distortion in its output is a. Class A b. Class B c. Class AB d. Class C Ans: B [4] The lowest output impedance is obtained in case of BJT amplifiers for a. CB configuration b. CE configuration c. CC configuration d. CE with RE configuration Ans: C [5] The upper cutoff frequency of an RC coupled amplifier mainly depends upon a. Coupling Capacitor b. Emitter bypass capacitor c. Output capacitance of signal source d. Inter-electrode capacitance and stray shunt capacitance Ans: D [6] Just as a voltage amplifier amplifies signal voltage, a power amplifier a. amplifies power b. amplifies signal current c. merely converts the signal ac power into the dc power d. merely converts the dc power into useful ac power Ans: D [7]An oscillator of the LC type that has a split capacitor in the circuit is a. Hartly oscillator b. Colpitts oscillator c. Weinbridge oscillator d. R-C phase shift oscillator Ans: B [8] The function of bleeder resistor in a power supply is a. the same as that of load resistor b. to ensure a minimum current drain in the circuit c. to increase the output dc voltage d. to increase the output current Ans: B [9] In a bistable multivibrator circuit, commutating capacitor is used a. to increase the base storage charge b. to provide ac coupling c. to increase the speed of response d. to provide the speed of oscillations Ans: C [10] Removing bypass capacitor across the emitter-leg resistor in a CE amplifier causes (A) increase in current gain. (B) decrease in current gain. (C) increase in voltage gain. (D)decrease in voltage gain. Ans: D Read more: http://electricalobjectivequestion.blogspot.com/2012/09/basic-electronicsobjectives-part-2.html#ixzz2LRLxAjw3 Basic Electronics :Part-3 Solved Objective Questions [1] When the elements of an RLC circuit are both magnitude scaled and frequency scaled, which quality is unaffected? a. resistor b. resonant frequency c. bandwidth d. quality factor Ans: D Answer [2] What kind of filter can be used to select a signal of one particular radio station? a. low pass b. high pass c. band pass d. band stop Ans: C Answer [3] A voltage source supplied a signal of constant amplitude, from 0 to 40kHz, to an RC lowpass filter. The load resistor experiences the maximum voltage at a. dc b. 10 kHz c. 20 kHz d. 40 kHz Ans: A Answer [4] The most commonly used amplifier in sample & hold circuits is A. A unity gain non-inverting amplifier B. A unity gain inverting amplifier C. An inverting amplifier with a gain of 10 D. An inverting amplifier with a gain of 100 Ans: B Answer [5] Three identical amplifiers with each one having a voltage gain of 50, input resistance of 1K & output resistance of 250,are cascaded. The open circuit voltage gain of combined amplifier is A. 49dB B. 51dB C. 98dB D. 102dB Ans: C Answer [6] The cascade amplifier is a multistage configuration of A. CC-CB B. CE-CB C. CB-CC D. CE-CC Ans: B Answer [7] The current gain of a BJT is A. gmr0 B. gm/r0 C. gmrπ D. gm/rπ Ans: C Answer [8] Introducing a resistor in the emitter of a common amplifier stabilizes the dc operating point against variations in A. Only the temperature B. Only the β of the transistor C. Both Temperature & β D. None of the above Ans: C Answer [9] Voltage Series feedback (also called series-shunt feedback) results in A. Increase in both input & output impedences B. Decrease in both input & output impedences C. Increase in input impedence & decrease in output impedence D. Decrease in input impedence & increase in output impedence Ans: C Answer [10] An amplifier without feedback has a voltage gain of a 50,input resistance of 1K & Output resistance of 2.5K. The input resistance of the current-shunt negative feedback amplifier using the above amplifier with a feedback of 0.2 is A. 1/11K B. 1/5K C. 5K D. 11K Ans: A Answer Read more: http://electricalobjectivequestion.blogspot.com/2012/10/basic-electronicspart-3-solved.html#ixzz2LRNOpMb1 Basic Electronics [Circuits Frequency Response] Objectives CIRCUITS FREQUENCY RESPONSE OBJECTIVE QUESTIONS: [1]Consider the parallel RLC circuit having R= 1, L= 1H, C=1F . What type of response will the circuit produce? a. Under damped b. Over damped c. Critically damped d. none of these Ans: A Answer [2] How much inductance is needed to resonate at 5 kHz with a capacitance of 12nF? a. 2652 H b. 11.844 H c. 3.333 H d. 84.33 mH Ans: D Answer [3] The difference between the half power frequencies is called the a. quality factor b. resonant frequency c. bandwidth d. cutoff frequency Ans: C Answer [4] A parallel RLC circuit has C=0.25F & L=2H. The value of R which will create unity damping factor is a. 1 b. 2 c. 0.5 d. 4 Ans: B Answer [5] A zero of the transfer function 10(s+1) H(s) = -----------(s+2)(s+3) is at a. 10 b. -1 c. -2 d. -3 Ans: B Answer [6] On the Bode magnitude plot, the slope of the pole 1/(5 + jω)2 is a. 20 dB/decade b. 40 dB/decade c. - 40 dB/decade d. -20 dB/decade Ans: C Answer [7] On the bode phase plot, the slope of [1 + j10ω - ω2/25]2 is a. 45°/decade b. 90°/decade c. 135°/decade d. 180°/decade Ans: D Answer [8] In an electric circuit, the dual of resistance is a. conductance b. capacitance c. open circuit d. inductance Ans: A Answer [9] In a series RLC circuit, which of these quality factors has the steepest curve at resonance? a. Q = 20 b. Q = 12 c. Q = 8 d. Q = 4 Ans:D Answer [10] In a parallel RLC circuit, the bandwidth B is directly proportional to R a. True b. False Ans:A Answer Read more: http://electricalobjectivequestion.blogspot.com/2012/09/basic-electronicscircuits-frequency.html#ixzz2LRLSj41U Power Semiconductors Solved Objective Questions: Part-I [1] Which of the following statements are correct? 1. Thyristor is current driven device 2. GTO is current driven device 3. GTR is current driven device 4. SCR is a pulse triggered device A.1 and 2 B.1, 2, 3 C.All D.4 only Ans:C Answer [2] Which of the following statements are correct? GTO is a pulse triggered device MOSFET is uni-polar device SCR is a bipolar device Continuous gate signal is not required to maintain the SCR to be in ON state A. 1, 2, 4 only B. 1, 2 only C. 4 only D. All Ans: D Answer [3] Which of the following is not a fully controlled semiconductor device? a. MOSFET b. IGBT c. IGCT d. SCR Ans: D . Only turn on of the SCR can be controlled whereas in other devices we can control both turn on and turn off Answer [4] Which of the following is not associated with p-n junction A. junction capacitance B. charge storage capacitance C. depletion capacitance D. channel length modulation Ans: D Answer [5] In a p-n junction diode under reverse bias, the magnitude of electric field is maximum at A. the edge of the depletion region on the p-side B. the edge of the depletion region on the n-side C. the p-n junction D. the center of the depletion region on the n-side Ans: C Answer [6] An n-channel JFET has IDSS=2mA, and Vp=-4V. Its transconductance gm=(in mA/V) for an applied gate to source voltage VGS=-2V is A. 0.25 B. 0.5 C. 0.75 D. 1 Ans: B Answer [7]The MOSFET switch in its on-state may be considered equivalent to A. resistor B. inductor C. capacitor D. battery Ans: C Answer [8] The effective channel length of a MOSFET in a saturation decreases with increase in A. gate voltage B. drain voltage C. source voltage D. body voltage Ans:B Answer [9] The early effect in a bipolar junction transistor is caused by A. Fast turn - on B. Fast turn - off C. Large collector - base reverse bias D. Large emmiter - base forward bias Ans: C Answer [10] MOSFET can be used as a A. Current controlled capacitor B. Voltage controlled capacitor C. Current controlled inductor D. Voltage controlled inductors Ans: B Answer Read more: http://electricalobjectivequestion.blogspot.com/2012/10/powersemiconductors-solved-objective.html#ixzz2LRMGo1Qp