ISCET AC Circuits and Analysis 3

Question 1

In a parallel RLC circuit at resonance, the impedance is:

Accepted Answer

Maximum (theoretically infinite for ideal components)

Answer

In an ideal parallel RLC circuit at resonance, the LC tank presents maximum (infinite) impedance because the circulating tank current is maximum while source current is minimum.

Question 2

The Q factor (quality factor) of a series resonant circuit is best described as:

Accepted Answer

The ratio of resonant frequency to bandwidth

Answer

Q = fr/BW, representing how selective (narrow-bandwidth) the resonant circuit is.

Question 3

What does the term 'skin effect' refer to in AC circuits?

Accepted Answer

Tendency of AC current to flow near the conductor surface at high frequencies

Answer

The skin effect causes AC current to concentrate near the outer surface of a conductor as frequency increases, effectively reducing the conductive cross-section.

Question 4

A low-pass RC filter has R = 1 kΩ and C = 0.1 µF. What is its cutoff frequency?

Accepted Answer

approximately 1592 Hz

Answer

fc = 1/(2πRC) = 1/(2π × 1000 × 0.0000001) ≈ 1592 Hz.

Question 5

In AC circuit analysis, Kirchhoff's Voltage Law (KVL) applies to:

Accepted Answer

Phasor (complex) voltages around a loop

Answer

KVL applies to AC circuits using phasor (complex number) representation, so phasor voltages around any closed loop sum to zero.

(ISCET) International Society of Certified Electronics Technicians Practice Test

(ISCET) International Society of Certified Electronics Technicians Practice Test

ISCET AC Circuits and Analysis 3