Master of Electrical Engineering Flashcards
7 cards from real ME or MEng Master of Engineering practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Master of Electrical Engineering flashcards as text
An op-amp integrator with R = 10 kΩ and C = 1 µF receives a 1 V DC step at t = 0. What is the output voltage after 10 ms (assuming ideal op-amp, starting from 0 V)?
Answer: -1 V
V_out = -(1/RC)∫V_in dt = -(1/0.01)·1·0.01 = -1 V.
In the Z-transform, what is the Z-transform of the unit step sequence u[n]?
Answer: 1/(1-z⁻¹), |z|>1
The Z-transform of u[n] is Σz⁻ⁿ for n≥0, which converges to 1/(1-z⁻¹) for |z|>1.
What is the primary advantage of using a synchronous rectifier over a diode rectifier in a DC-DC converter output stage?
Answer: Lower conduction losses due to MOSFET R_DS(on) vs diode forward voltage
MOSFET R_DS(on) voltage drop (mΩ range) is much smaller than a diode's ~0.5-1 V forward drop, significantly reducing conduction losses.
Maxwell's equation ∇ × H = J + ∂D/∂t includes the displacement current term ∂D/∂t, which was added by Maxwell to:
Answer: Ensure conservation of charge and allow electromagnetic wave propagation
Maxwell added ∂D/∂t to make Ampère's law consistent with charge continuity (∇·J + ∂ρ/∂t = 0) and this addition predicts electromagnetic wave propagation.
In a BJT common-emitter amplifier, the Early effect causes:
Answer: A finite output resistance due to base-width modulation
The Early effect (base-width modulation) causes I_C to increase slightly with V_CE, modeled as finite output resistance r_o = V_A/I_C.
Which filter topology is best suited for implementing a maximally flat (Butterworth) low-pass response with minimal sensitivity to component tolerances?
Answer: State-variable (biquad) topology
The state-variable biquad topology independently controls Q and ω₀, giving low sensitivity to component variations for high-order Butterworth designs.
In a power system, a 'bus impedance matrix' (Z_bus) is used to compute fault currents. For a bolted three-phase fault at bus k, the fault current is:
Answer: V_k(pre-fault) / Z_kk
For a bolted fault at bus k, I_fault = V_k(pre-fault) / Z_kk, where Z_kk is the Thevenin impedance seen at bus k.