The half-power frequencies, ω₁ and ω₂, are defined as the frequencies where the magnitude of the input admittance of a parallel resonant circuit is greater than its magnitude at resonance by what factor?

Correct answer: sqrt(2)

Explanation

Half-power frequencies are named because at these points, the power delivered to the circuit is half of the maximum power delivered at resonance. This corresponds to the voltage or current being 1/√2 of its peak value, and the admittance being √2 times its minimum value.

Other questions

Question 1

In a two-terminal electrical network containing at least one inductor and one capacitor, what is the definition of resonance?

Question 2

What is the formula for the resonant frequency, ω₀, of a parallel RLC circuit?

Question 3

A parallel resonant circuit is composed of an 8 kOhm resistor, a 50 mH inductor, and an 80 nF capacitor. What is the resonant frequency, ω₀, for this circuit?

Question 4

What is the quality factor, Q, of a resonant circuit defined as?

Question 5

For a parallel RLC circuit, what is the expression for the quality factor at resonance, Q₀?

Question 6

A parallel RLC circuit has L = 2 mH, C = 10 nF, and a quality factor Q₀ = 5. What is the value of the resistor R?

Question 7

What is the relationship between the exponential damping coefficient α and the resonant frequency ω₀ and quality factor Q₀ for a parallel RLC circuit?

Question 9

What is the formula for the bandwidth, B, of a resonant circuit in terms of its resonant frequency ω₀ and quality factor Q₀?

Question 10

For a high-Q circuit where Q₀ is greater than or equal to 5, the upper and lower half-power frequencies, ω₁ and ω₂, can be approximated by what expression?

Question 11

A parallel resonant circuit has a resonant frequency f₀ = 440 Hz and Q₀ = 6. Using the approximate expressions for a high-Q circuit, what are the estimated lower and upper half-power frequencies, f₁ and f₂?

Question 12

By the principle of duality, what is the quality factor Q₀ for a series RLC circuit?

Question 13

A series resonant circuit is composed of a 10 Ohm resistor, a 200 nF capacitor, and a 2 mH inductor. What is the quality factor, Q₀, of this circuit?

Question 14

What is the primary difference in impedance characteristics at resonance between a series RLC circuit and a parallel RLC circuit?

Question 15

Magnitude scaling is defined as the process by which the impedance of a two-terminal network is increased by a factor of Km. How must L and C be scaled to achieve this?

Question 16

Frequency scaling is defined as the process by which the frequency at which any impedance occurs is increased by a factor of Kf. How must L and C be scaled to achieve this?

Question 17

A parallel resonant circuit has R = 2.5 Ohm, L = 0.5 H, and C = 2 F. It is to be scaled to have a new resonant frequency of 5 x 10^6 rad/s and a new impedance maximum of 5000 Ohm. What are the new component values R', L', and C'?

Question 18

The value of a transfer function's magnitude |H(jω)| in decibels (dB) is defined by which formula?

Question 19

A transfer function magnitude |H(jω)| increases by a factor of 10. How much does its value in decibels (HdB) increase?

Question 20

In a Bode magnitude plot, what is the slope of the high-frequency asymptote for a simple zero, H(s) = 1 + s/a?

Question 21

For a simple zero H(s) = 1 + s/a, what is the difference between the exact magnitude and the asymptotic magnitude at the corner frequency ω = a?

Question 22

What are the three straight-line segments that form the asymptotic phase response for a simple zero H(s) = 1 + s/a?

Question 23

What is the Bode magnitude plot for the transfer function H(s) = 1 / (1 + s/a)?

Question 24

For the transfer function H(s) = -2s / [(1 + s/10)(1 + s/20,000)], what is the asymptotic magnitude in dB in the flat region between ω = 10 rad/s and ω = 20,000 rad/s?

Question 25

What is the slope of the high-frequency asymptote for a transfer function with a quadratic zero, H(s) = 1 + 2ζ(s/ω₀) + (s/ω₀)²?

Question 26

For a quadratic factor H(s) = 1 + 2ζ(s/ω₀) + (s/ω₀)², what is the correction needed at the corner frequency ω = ω₀ when the damping factor ζ = 0.5?

Question 27

Which type of filter passes frequencies below a cutoff frequency and significantly attenuates frequencies above it?

Question 28

The transfer function for a simple passive RC low-pass filter (output across the capacitor) is H(s) = Vout/Vin = 1 / (1 + RCs). Where is the corner frequency located?

Question 29

To design a simple passive RC high-pass filter with a corner frequency of 3 kHz, a 4.7 kOhm resistor is chosen. What is the required capacitance?

Question 30

A simple RLC series circuit is used as a bandpass filter with the output taken across the resistor. The bandwidth B of this filter is given by what expression?

Question 31

An active low-pass filter is to be designed with a cutoff frequency of 10 kHz and a DC voltage gain of 40 dB. The design uses a noninverting amplifier. What is the required ratio of Rf/R1 for the amplifier?

Question 32

What is a primary advantage of using active filters (e.g., with op-amps) over passive filters?

Question 33

The low-pass Butterworth filter is known for what characteristic in its passband?

Question 34

In a Sallen-Key low-pass filter prototype with R1 = R2 = R and C1 = C2 = C, what is the required amplifier gain G for a second-order Butterworth response?

Question 35

To design a third-order Butterworth filter, what factors must the transfer function denominator contain?

Question 36

What does a damping factor ζ > 1 imply for a quadratic factor H(s) = 1 + 2ζ(s/ω₀) + (s/ω₀)²?

Question 37

For a series combination of a 100 mH inductor and a 5 Ohm resistor, what is the parallel equivalent resistance, Rp, at a frequency of 1000 rad/s, using the high-Q approximation?

Question 38

A network is scaled in frequency by a factor of Kf = 2. If the original impedance was found at a frequency ω, at what frequency will the same impedance value be found in the new network?

Question 39

At resonance in a simple parallel RLC circuit, what is the net current flowing into the parallel LC combination?

Question 40

A circuit's frequency response is measured in decades. What does one decade represent?

Question 41

What is the key feature of a Chebyshev filter's passband response compared to a Butterworth filter?

Question 42

In the context of the Bode plot for H(s) = 1 + s/a, the frequency 'a' is often described as the corner, break, or half-power frequency. What other name is it given?

Question 43

A series RLC circuit has a resonant frequency of 50 krad/s and Q₀ = 10. A voltage of 100 mV is applied. What is the approximate current magnitude if the operating frequency is 48 krad/s?

Question 44

The input impedance of a network is Z(s) = 2 + 5s. How would its magnitude vary as a function of frequency ω, when σ=0?

Question 45

What type of filter is created by taking the output across the resistor in a series RLC circuit?

Question 46

To convert a series combination of a resistance Rs and a reactance Xs to a parallel equivalent (Rp, Xp), which statement about their quality factors (Q) must be true?

Question 47

What is the slope of the Bode phase plot for a transfer function H(s) = s?

Question 48

A circuit with a transfer function H(s) is scaled in magnitude by Km = 10 and in frequency by Kf = 100. If the original transfer function was Z(s), what is the new transfer function Z''(s)?

Question 49

What is the primary trade-off in choosing a Chebyshev filter over a Butterworth filter of the same order?

Question 50

A transfer function has a magnitude of 0.5. What is its value in decibels (dB)?