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
In a three-phase induction motor, if the rotor resistance is doubled while the load torque remains constant, what primarily happens to the slip?
Answer: Slip doubles
In the equivalent circuit model, slip is proportional to rotor resistance for a given torque, so doubling rotor resistance doubles the slip.
Which modulation scheme achieves the highest spectral efficiency in a bandwidth-limited wireless channel?
Answer: 256-QAM
256-QAM encodes 8 bits per symbol, giving the highest spectral efficiency (bits/s/Hz) among these options.
For a buck-boost DC-DC converter operating in continuous conduction mode, what is the voltage conversion ratio M = V_out/V_in as a function of duty cycle D?
Answer: -D/(1-D)
The buck-boost converter inverts polarity, giving M = -D/(1-D), where the negative sign indicates output polarity reversal.
In CMOS logic design, which phenomenon causes dynamic power dissipation?
Answer: Charging and discharging of load capacitances
Dynamic power P = α·C·V²·f arises from charging and discharging load capacitances at each switching event.
A transmission line has a characteristic impedance Z₀ = 50 Ω and is terminated with Z_L = 100 Ω. What is the reflection coefficient Γ?
Answer: 0.33
Γ = (Z_L - Z₀)/(Z_L + Z₀) = (100-50)/(100+50) = 50/150 = 1/3 ≈ 0.33.
In power systems, the per-unit system is used primarily to:
Answer: Simplify calculations across different voltage levels by normalizing quantities
Per-unit normalization removes the transformer turns-ratio effect, allowing uniform analysis across multiple voltage levels.
Which control strategy is most commonly used in field-oriented control (FOC) of AC motors to decouple torque and flux?
Answer: Park transformation to d-q rotating reference frame
FOC applies the Park (d-q) transformation so flux-producing and torque-producing current components can be controlled independently like a DC motor.