Electrical Engineering Fundamentals Interview Practice Test

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• In ADC design, increasing the sampling rate typically increases which of the following?
• What is resistance?
• In a bipolar junction transistor (BJT), what are the three terminals called?
• What is a diode?
• The cutoff angular frequency ωc of an RC low-pass filter is given by what expression?
• Which component stores energy in a magnetic field?
• What is the primary purpose of placing decoupling capacitors close to IC power pins?
• Which summary captures the core criterion for feedback stability in control systems?
• What is a key limitation of instrumentation amplifiers in precision sensor applications?
• How do voltage and current behave in a series circuit?
• In a purely inductive circuit with a DC input after a long time, the inductor behaves as which?
• What information does a Bode plot convey about a linear time-invariant system?
• The term load impedance under maximum power transfer refers to what relationship to source impedance?
• Which statement about RMS voltage is true?
• For a second-order RLC circuit, which statement best describes its dynamic behavior?
• Describe enhancement-mode NMOS operation and how gate voltage controls channel conduction.
• In Thevenin/Norton circuit equivalence, what does Voc represent?
• What is a ground loop and how is it mitigated in lab setups?
• If a simple AC voltage divider has Z1 equal to Z2, what fraction of the source voltage Vs appears across Z2?
• Which equation expresses Ohm's Law?
• Why do we want infinitely high input impedance in an ideal opamp?
• Which statement correctly compares the SAR and sigma-delta ADC architectures in terms of resolution, speed, and noise shaping?
• What is a transistor?
• What is the MOSFET threshold voltage and how does it affect switching characteristics?
• What is a magnetic field?
• What does Safe Operating Area define in power electronics?
• RMS voltage is used to provide power dissipation calculations in AC circuits so that results can be compared with DC circuits.
• How is RMS voltage defined?
• Explain the concept of MOSFET subthreshold conduction and why it matters for leakage power.
• Describe NPN transistor operation in the active region and the role of the base-emitter junction.
• For a sinusoidal voltage with peak Vp, what is the RMS value?
• How do half-wave and full-wave rectifiers compare in operation and in the average output voltage for an ideal transformer with peak input Vm?
• In the Laplace-domain representation of a system, the location of poles determines stability. If a pole has a negative real part, the system response is:
• Which statement expresses Kirchhoff's current law for a node?
• What is the energy stored in a capacitor with capacitance C and voltage V?
• What is a Schmitt trigger and how does hysteresis improve noise immunity?
• Why do we want infinite voltage gain in an ideal opamp?
• What is an inductor?
• Which statement best describes a guideline for selecting an ADC reference voltage?
• If resistance increases while voltage remains constant, what happens to current?
• Which expression correctly defines reactive power Q in a balanced three-phase system?
• Why is subthreshold conduction important for leakage power in modern ICs?
• Which statement best characterizes an operational amplifier in open-loop versus closed-loop configurations?
• What is a diode?
• In an analog circuit, how is the signal described?
• What is the correct expression for complex power S in terms of voltage and current?
• Two resistors 2 Ω and 3 Ω are connected in parallel. What is the equivalent resistance?
• Which statement about phasors is correct for a sinusoidal signal v(t) = Vm cos(ωt + φ)?
• In RF impedance matching, the load impedance should be what with respect to the source impedance to minimize reflections?
• Which part determines the voltage step ratio in a transformer?
• Which description correctly defines a PID controller and the role of each term (P, I, D) in system response?
• Define load line analysis for transistors and how it helps in biasing.
• Quantization noise is proportional to which of the following?
• Which configuration yields a low-pass filter?
• Where should the quiescent point be placed for maximum symmetric output swing in a common-emitter amplifier?
• In an AC circuit, what is the impedance of a capacitor with capacitance C and angular frequency ω?
• Derive the transfer function for an inverting op-amp with feedback resistor Rf and input resistor Rin.
• What does the RMS value represent for an AC voltage or current, and how is it used in power calculations?
• What is a second order circuit?
• What is an FPGA?
• The Fourier series concept states that any periodic signal can be represented as ...
• What is impedance matching and why is it important?
• Which PCB layout practice helps minimize noise and EMI?
• What is Alternating Current (AC)?
• Which method is commonly used to achieve impedance matching on a transmission line?
• Why is an anti-aliasing filter used before sampling in ADC design?
• In a standard, generic op-amp model, which statement correctly describes open-loop gain, input impedance, and how closed-loop gain is set?
• Which statement best describes the transient response in RC circuits and how it is characterized?
• What is a transfer function in linear control systems?
• Describe the forward conduction threshold of a silicon diode and its I-V behavior in forward and reverse bias.
• What technique can be used to achieve impedance matching in audio or sensor interfaces?
• What is the difference between an alternator and a generator?
• In an ideal transformer with 50 turns on the primary and 100 turns on the secondary, what is the voltage relationship?
• What is electromagnetic interference and which mitigation techniques are commonly used in PCB design?
• Which statement is true about capacitors?
• Which ADC type is known for high resolution with oversampling and noise shaping, especially at low frequencies (audio applications)?
• In an RLC circuit, which components are present?
• Define mutual inductance and the coupling coefficient; what is the expression for mutual inductance M between two coils with self-inductances L1 and L2 and coupling coefficient k?
• For maximum power transfer, how must the load reactance relate to the source reactance?
• How does the root locus help in control design?
• For maximum power transfer, how must the load resistance compare to the source resistance?
• Which condition yields maximum power transfer from a source to a load in an AC circuit?
• Why is biasing important in transistor amplifiers and what is the Q-point?
• What is a valence electron?
• Describe the concept of wave propagation velocity in transmission lines and the role of the speed of light in vacuum as a baseline for RF design.
• Three-phase power system distributes the workload between how many wires alongside a neutral?
• If the resistance in a series circuit doubles, what happens to the current?
• Which characteristic is a healthiness feature of instrumentation amplifiers when interfacing sensors?
• What are logic gates?
• Which statement describes Ohm's law for a linear resistor?
• In a parallel circuit, which statement describes the relationship between voltage across branches and current in branches?
• What is the difference between synchronous and asynchronous digital circuits?
• Which statement is NOT true about achieving maximum power transfer in an AC circuit?
• Which statement best describes a full-bridge rectifier?
• What does a Fourier transform do to a time-domain signal?
• Which of the following accurately contrasts time-domain and frequency-domain analyses?
• Which equation correctly relates Thevenin and Norton equivalents?
• What is mutual inductance?
• What is the primary mechanism of attenuation in a notch filter tuned to a target frequency f0?
• What is the primary purpose of impedance matching in RF systems?
• Capacitors in series have an equivalent capacitance equal to what?
• Reactance arises from which components?
• Which statement about the Laplace transform's role in circuit analysis is correct?
• Which of the following best describes a typical use of op-amps in analog circuits?
• The maximum power transfer theorem applies to which type of networks?
• In an op-amp circuit using negative feedback, which effects are typically observed?
• Which statement correctly describes power factor and a method to improve it in an inductive AC circuit?
• Direct current (DC) has which characteristic?
• In an ADC, what is the difference between resolution and sampling rate, and how is quantization error determined?
• What is the Norton current In in terms of Thevenin parameters?
• Which statement best describes a first-order RC low-pass filter with a resistor in series and a capacitor to ground?
• In a simple Ohm's law scenario, if voltage is constant and resistance increases, what happens to current?
• What is the permissible range for the coupling coefficient k in mutual inductance?
• If an op-amp had nonzero output impedance, what would be the effect when driving a load?
• What is the primary purpose of the reference voltage in ADC designs?
• Which statement accurately distinguishes passive filters from active filters, with an example of each?
• Which of the following is a basic logic gate?
• How does a transformer work?
• What are the practical benefits of a voltage follower (unity-gain buffer) in circuit design?
• Define input-referred noise and how you would minimize it in an amplifier design.
• What is the significance of gain-bandwidth product in operational amplifiers?
• In a DC motor, what is the role of back EMF?
• Which of the following statements correctly represents the relationships for an ideal transformer?
• Which statement is true for an ideal transformer regarding energy transfer?
• Which expression correctly defines the apparent power S in a balanced three-phase system?
• According to the Nyquist sampling theorem, what is the minimum sampling frequency to capture a signal with the highest frequency component f_max without aliasing?
• What is current?
• To improve power factor in an AC circuit with an inductive load, which approach is effective?
• In a balanced three-phase system, which expression correctly gives real power P in terms of V_LL, I, and cosφ?
• Which of the following is an ideal op-amp characteristic?
• Which statement correctly describes the Norton equivalent in relation to Thevenin's theorem?
• For a first-order RC low-pass filter, which statement is true about its cutoff frequency?
• Differentiate between NPN and PNP transistor operation and typical biasing configurations (CE, CB, CC).
• What energy form do inductors store?
• What are the conventional units of apparent power S?
• In a linear time-invariant system, the output response to a unit step input is obtained by convolving the step input with the system's impulse response h(t).
• How does an AC generator work?
• What is the Q-point in transistor biasing?
• What is reactance?
• In a microcontroller interfacing with an analog sensor using a simple ADC and PWM, what is the role of PWM?
• Which description correctly represents Thevenin's theorem for a linear circuit as seen from two terminals?
• Which statement best describes a linear resistor's V-I relationship?
• What is an OpAmp?
• How do capacitors behave at low and high frequencies?
• Which of the following is present in the source material as a logic gate example?
• Which statement correctly describes Norton versus Thevenin equivalents?
• Which statement about alternators and generators is correct?
• A field programmable gate array is best described as?
• How do you block out electromagnetic fields?
• In a digital circuit, what values can be represented?
• In a transmission line, what primarily determines the amount of reflection at a discontinuity?
• Define impedance for a resistor-inductor-capacitor circuit.
• What is the DC output behavior of a high-pass RC filter to a constant input?
• According to the Nyquist-Shannon sampling theorem, what minimum sampling rate is required to reconstruct a bandlimited signal in ADC design?
• What is the impedance of a series R-L-C circuit at angular frequency ω?
• What happens when two positively charged particles are placed next to each other?
• Briefly describe the Nyquist stability criterion in control theory.
• What is charge?
• In an op-amp circuit, what is the effect of negative feedback on performance?
• Short-circuit current rating indicates what?
• Which statement about the Q factor is true for a resonant circuit?
• Explain the concept of common-mode rejection ratio (CMRR) in differential amplifiers and why it matters.
• What factors influence the mutual inductance between two coils?
• Derive the transfer function for a non-inverting op-amp with feedback network R_f (from output to - input) and R_g (from - input to ground).
• For a series RLC circuit, what is the resonant frequency f0?
• What is the transfer function of a first-order RC high-pass filter?
• If the power factor PF equals cos(phi) = 0.8, what does the angle phi represent in the voltage-current relationship?
• What is the ideal op-amp model and the meaning of a virtual short in negative feedback?
• In a three-phase system, the three wires carry the power with a neutral used for grounding.
• In digital design, what is a Karnaugh map and how is it used to simplify Boolean expressions?
• Which sequence describes finding a Thevenin equivalent?
• Why is the gain of an ideal op-amp considered to be independent of frequency?
• What is the equivalent resistance of two resistors in series?
• Time constant concept for RC networks.
• How do capacitors behave in series and parallel?
• RMS voltage enables power dissipation calculations in AC circuits that are comparable with DC circuits.
• In a full-bridge rectifier, how many diodes conduct at any given half-cycle?
• Why zero output impedance in an ideal op-amp?
• Which statement best describes a first-order filter and how it differs from a second-order filter?
• Explain MOSFET operation and the difference between enhancement-mode and depletion-mode devices.
• What is a capacitor?
• What is the power factor in a sinusoidal AC system?
• For a series RL circuit with a step input Vs, which expression gives the current i(t) for t ≥ 0?
• What is an RLC circuit?
• In a solar photovoltaic cell, how does irradiance affect its I-V characteristics?
• Which statement best describes signal integrity and its common issues in high-speed digital design?
• Which statement accurately describes Thevenin and Norton equivalents?
• How do voltage and current behave in a parallel circuit?
• In terms of energy behavior, which statement about reactance is accurate?
• For a series RLC circuit, which expression defines the quality factor Q?
• An LC resonant circuit: If L is increased while keeping C fixed, what happens to the resonant frequency f0 = 1/(2π√(LC))?
• What does reactance do in a circuit?
• How is the total admittance Y of a parallel R-L-C circuit formed?
• What is the ideal diode model, and what is a key limitation of it in real circuits?
• What is a rectifier?
• What do capacitors oppose?
• What is a transformer?
• What is electromagnetic compatibility (EMC) and a common mitigation technique?
• In the ideal op-amp model, what is the input impedance and how does negative feedback affect the relation between V+ and V−?
• What do inductors oppose?
• In electrical systems, how do earth ground, equipment ground, and protective ground differ?
• Simplify the boolean expression (A AND NOT B) OR (A AND B).
• Capacitors in parallel have what relationship for total capacitance?
• What is the square root of -1?
• What is Direct Current (DC)?
• What is voltage?
• How do inductors behave at low and high frequencies?
• Which statement best describes a DAC?
• Describe the operation of a BJT transistor in active mode and the role of the base-emitter junction.
• Which statement correctly defines Kirchhoff's Current Law (KCL)?
• What is power factor and how is it calculated in AC circuits?
• Resonance condition for a series RLC circuit.
• What is the purpose of a decoupling capacitor in a power supply, and where should it be placed to be most effective?
• In circuit analysis, what is the purpose of Laplace transforms and how is the transform variable defined?
• Which relation correctly connects apparent power S with real power P and reactive power Q in a sinusoidal system?
• Which of the following are typical errors associated with ADC conversions?
• What is the energy stored in an inductor with inductance L and current I?
• If a source has no reactance, maximum power transfer occurs when the load resistance equals the source resistance.
• Before sampling a continuous-time signal, why is an anti-aliasing filter typically used?
• If a transformer has more turns on its secondary than the primary, it is a
• What is the primary function of an op-amp?
• Which of the following best describes a Faraday cage?
• What primarily enables energy transfer in a transformer?
• In a simple AC voltage divider with series impedances Z1 and Z2 driven from a source Vs, the output voltage across Z2 is:
• Which statement describes the SI unit of the electric field?
• Which domain is most natural to analyze a system's response to a sudden step input?
• What is the goal of impedance matching in audio systems?
• For a phasor voltage V and current I with power factor cos(phi), which set of equations correctly defines real, reactive, and apparent power and the power factor?
• Which statement about autotransformers is true?
• For an RC low-pass filter, what is the definition of the cutoff frequency in terms of output magnitude?
• Terminating a transmission line with its characteristic impedance helps to minimize reflections and maximize power transfer.
• In an ADC, what is quantization error?
• In an enhancement-mode NMOS device, what is the channel status when V_GS is below threshold?
• In a series RLC circuit, the magnitude of the total impedance is given by which expression?
• What is the purpose of impedance matching in RF circuits and why does it matter for maximum power transfer?
• For an RC circuit with a step input Vs at t = 0, what is the expression for the capacitor voltage v_C(t)?
• Which configuration yields a high-pass filter?
• In a switching power supply, what is the role of a flyback diode?