FREE BEE Bachelor of Electrical Engineering DC and AC Circuit Analysis Questions and Answers

Question 1

According to Thevenin's theorem, any linear electrical network with two terminals can be replaced by an equivalent circuit consisting of what?

Accepted Answer

A voltage source in series with a resistor

Answer

A current source in parallel with a resistor

Answer

A voltage source in parallel with a capacitor

Answer

A current source in series with an inductor

Question 2

In a series RLC circuit, what condition results in a critically damped response to a step input?

Accepted Answer

(R/2L)^2 = 1/LC

Answer

(R/2L)^2 > 1/LC

Answer

(R/2L)^2 < 1/LC

Answer

R = 0

Question 3

A design engineer needs to correct the power factor of an industrial motor that presents a lagging (inductive) load. Which of the following is the most common and effective method to improve the power factor towards unity?

Accepted Answer

Adding a capacitor in parallel with the motor.

Answer

Adding a resistor in series with the motor.

Answer

Adding an inductor in parallel with the motor.

Answer

Increasing the source voltage.

Question 4

For maximum power transfer in an AC circuit, what must be the relationship between the load impedance (ZL) and the Thevenin equivalent impedance (Zth) of the source network?

Accepted Answer

ZL is the complex conjugate of Zth

Answer

ZL = Zth

Answer

ZL = -Zth

Answer

ZL is the reciprocal of Zth

Question 5

When applying the superposition theorem to a circuit containing multiple independent sources, how are the other sources treated when calculating the contribution of a single voltage source?

Accepted Answer

All other voltage sources are replaced by short circuits, and all current sources are replaced by open circuits.

Answer

All other voltage sources are replaced by open circuits, and all current sources are replaced by short circuits.

Answer

All other sources are removed from the circuit entirely.

Answer

All other sources are left in the circuit, but their values are set to zero.

Question 6

Which of the following statements accurately describes the relationship between a Thevenin equivalent circuit and a Norton equivalent circuit?

Accepted Answer

They are duals of each other; a Norton equivalent can be derived from a Thevenin equivalent and vice-versa.

Answer

They are completely independent and cannot be derived from one another.

Answer

The Norton resistance is the reciprocal of the Thevenin resistance.

Answer

A Thevenin circuit is used for DC analysis, while a Norton circuit is used for AC analysis.