All Free Electrical Engineering MCQs with Answers

• A. increases
• B. minimizes
• C. does not have any effect on
• D. any of the above

Explanation: Integral compensation accumulates the error over time and drives the steady-state error toward zero for suitable systems.

• A. The poles of the transfer function for a set of parameter values
• B. The bandwidth of the system
• C. The response of a system to a step input
• D. The frequency response of a system
• E. None of the above

Explanation: A root locus plots the locations of the closed-loop poles as a system parameter, usually the gain, varies.

• A. Signal flow graph
• B. Analogous table
• C. Output-input ratio
• D. Standard block system
• E. None of the above

Explanation: A signal-flow graph represents the relationships among system variables, and Mason’s gain formula can be used to obtain the transfer…

• A. Ramp input signal
• B. Sinusoidal input signal
• C. Unit impulse input signal
• D. Exponentially decaying signal

Explanation: A unit impulse excites all dynamic modes of a linear system and its response directly gives the system’s impulse response, from which the…

• A. Manipulated variable
• B. Zero sequence
• C. Actuating signal
• D. Primary feedback

Explanation: The actuating, or error, signal is the algebraic difference between the reference input and the feedback signal, usually written as e(t) =…

• A. system stability
• B. sensitivity
• C. gain
• D. effects of disturbing signals

Explanation: Negative feedback generally improves stability by reducing the tendency of the system to oscillate or diverge.

• A. The system is at rest and no energy is stored in any of its components
• B. The system is working with zero stored energy
• C. The system is working with zero reference signal

Explanation: Zero initial condition means the system starts from rest, so its energy-storing elements such as capacitors and inductors have no…

• A. Input
• B. Actuating
• C. Feedback
• D. Reference

Explanation: The actuating or error signal is the difference between the reference and feedback signals.

• A. Linear and time-in variant systems
• B. Linear and time-variant systems
• C. Linear systems
• D. Non-linear systems
• E. None of the above

Explanation: The conventional transfer function is defined using zero initial conditions for a linear time-invariant system, so it is independent of…

• A. disturbance
• B. command
• C. control element
• D. reference input

Explanation: A disturbance is an unwanted input other than the reference command that changes the controlled variable.

• A. inertia forces
• B. internal forces
• C. stored energy
• D. friction

Explanation: Transient response results from the release, redistribution, or dissipation of energy initially stored in system elements such as…

• A. voltage
• B. current
• C. capacitance
• D. charge
• E. none of the above

Explanation: Temperature difference is the driving potential in a thermal system, just as voltage is the driving potential in an electrical circuit.

• A. velocity
• B. pressure
• C. air flow
• D. air flow rate

Explanation: Air-flow rate represents the rate of movement of air, just as electric current represents the rate of movement of charge.

• A. current
• B. charge
• C. inductance
• D. capacitance

Explanation: In the force-voltage analogy, force corresponds to voltage and velocity corresponds to current.

• A. head
• B. liquid flow
• C. liquid flow rate
• D. none of the above

Explanation: Liquid head is the potential that drives liquid flow, so it corresponds to electrical voltage.

• A. charge
• B. resistance
• C. reciprocal of inductance
• D. reciprocal of conductance
• E. none of the above

Explanation: The viscous-friction term is proportional to velocity, just as resistance is proportional to current in the voltage analogy.

• A. charge
• B. current
• C. inductance
• D. resistance

Explanation: Mechanical mass opposes changes in velocity, while inductance opposes changes in current.

• A. momentum
• B. velocity
• C. displacement
• D. mass

Explanation: In the force-current analogy, force corresponds to current and velocity corresponds to voltage.

• A. Error detector
• B. Final control element
• C. Sensor
• D. Oscillator

Explanation: An automatic control system commonly uses an error detector, sensor, and final control element to measure and correct the output.

• A. It leads to slow speed of response
• B. It leads to low relative stability
• C. Noise is proportional to band width
• D. None of the above

Explanation: A wider bandwidth allows more noise, because the total noise power generally increases with the frequency range passed by the system.