60 Questions
What is the main characteristic of ideal filters in terms of output voltage?
Stops completely at the cut-off frequency
Why are highly selective and steep response curves impossible to achieve in practical filters?
Design limitations and practical constraints
At what frequencies does the output voltage decrease gradually in a low-pass filter?
At frequencies above the cut-off frequency
What configuration does an RC low-pass filter use?
Resistor in series with capacitor
What happens to attenuation in a high-pass filter as frequency increases?
Attenuation decreases gradually
Why can't practical filters achieve ideal response curves?
Design limitations and constraints
What happens to the capacitive reactance (XC) as the frequency increases in an RC high-pass filter?
XC decreases
Which statement best describes the behavior of an RL high-pass filter at frequencies below the cut-off frequency?
Most of the generator voltage will be across the resistor and very little voltage will appear across the output inductor.
What happens to the inductive reactance (XL) as the frequency increases in an RL high-pass filter?
XL increases
What is the output voltage of an RC high-pass filter at the cut-off frequency (fCO) relative to the maximum applied voltage?
70.7%
Which statement best describes the performance of RC and RL high-pass filters?
The performance of RC and RL high-pass filters is the same.
At frequencies below the cut-off frequency in an RC high-pass filter, what happens to the voltage across the capacitor?
The voltage across the capacitor is very high.
What happens to the voltage division ratio when the supply frequency changes?
It changes, causing the output voltage to vary
How can filters be designed to pass or eliminate desired frequencies?
By adjusting the resistance and capacitance values of the voltage divider
What condition is known as resonance in an LCR circuit?
When inductive reactance equals capacitive reactance
What is the characteristic of a resonant circuit?
It is totally resistive
How does the inductive reactance change with an increase in frequency?
It increases
How does the capacitive reactance change with a decrease in frequency?
It increases
What type of filter is described in the text?
Low-pass filter
How does the output voltage of a voltage divider compare to the input voltage in an AC circuit?
The output voltage is always less than the input voltage
How does the inductive reactance (XL) vary with frequency?
XL is proportional to frequency
How does the capacitive reactance (XC) vary with frequency?
XC is inversely proportional to frequency
In an RL low-pass filter, what happens to the voltage across the inductor as frequency increases?
The voltage across the inductor increases
What is the primary purpose of an RL low-pass filter?
To attenuate high frequencies while allowing low frequencies to pass
What is the primary ability of an LCR circuit?
To separate frequencies
In a series resonant circuit at resonance, what is the characteristic of the impedance?
Resistive and low value
In a parallel resonant circuit (tank circuit) at resonance, what is the characteristic of the impedance?
Resistive and high value
What do series LC resonant circuits offer regarding current flow?
Minimum opposition at resonant frequency, maximum opposition at other frequencies
What do parallel LC resonant circuits offer regarding current flow?
Maximum opposition at resonant frequency, minimum opposition at other frequencies
What is the primary application of resonant circuits mentioned in the text?
Filters
What is the main cause of copper losses in a transformer?
Resistance of the primary and secondary windings
Which type of transformer typically has the highest efficiency?
Large electrical utility distribution transformers
What is the main purpose of minimizing losses in a transformer?
To reduce the undesirable conversion of electrical energy into heat energy
What type of loss is caused by the resistance of the transformer windings?
Copper loss
What is the main reason large power transformers have higher efficiency compared to smaller transformers?
They have lower eddy current and hysteresis losses
What is the primary cause of heat generation in a transformer?
All of the above
What is the total circuit resistance when a 24 V source is connected to a 6 Ω load?
30 Ω
In the first example provided, what is the relationship between the power consumed by the load and the power in the source?
Equal
At what circuit current does the source consume 6 W when connected to an 18 Ω load?
1.5 A
In which region should Rload be less than Rsource to minimize heat generation in the source?
Region 3
What does connecting an 18 Ω load to a 24 V source result in terms of power in the load?
18 W
If a 24 V source is connected to a 6 Ω load, what is the circuit current?
2 A
What is the impedance transformation ratio when the impedance values of each side of the transformer are compared in a ratio?
16:1
In terms of transformer ratings, what determines the maximum current that can be carried by a transformer winding?
Insulation between the windings
What is the relationship between the impedance transformation ratio and the turns ratio squared in a transformer?
Directly proportional
Which factor determines the maximum voltage that can safely be applied to any winding in a transformer?
Insulation between the windings
How does a higher maximum voltage on transformer windings relate to the type of insulation used between them?
Better (thicker) insulation allows a higher voltage
What is the relationship between the voltage transformation ratio and the impedance transformation ratio in the transformer discussed?
Directly proportional
What is the main purpose of impedance matching in a circuit?
To maximize the power transferred from the source to the load
In the example provided, what is the power dissipated in the $6 \Omega$ load when connected to the $24 V$ source with $6 \Omega$ internal impedance?
$18 W$
What happens when the load impedance is not matched to the source impedance?
The power transfer is not maximized
In the example provided, what is the power dissipated in the $6 \Omega$ source when connected to the $6 \Omega$ load?
$54 W$
What is the main reason why the source in the example is consuming three times the power of the load?
The load impedance is not matched to the source impedance
What is the key concept demonstrated in the example of the $24 V$ source with $6 \Omega$ internal impedance connected to a $2 \Omega$ load?
The need for impedance matching to maximize power transfer
What is the primary function of an auto-transformer as described in the text?
To provide a variable-output voltage
What is the relationship between the voltage across the secondary winding and the voltage across the primary winding in an auto-transformer?
The secondary voltage has the same relationship to the primary voltage as if they were two distinct windings
What does the movable tap in an adjustable auto-transformer allow the user to do?
Both increase and decrease the voltage relative to the primary voltage
What is the relationship between the voltages available at the different tap points on an adjustable auto-transformer?
The voltage between points A and B can be either higher or lower than the voltage between points A and C, depending on the tap position
What is the primary difference between a transformer and an auto-transformer as described in the text?
Auto-transformers have a single coil of wire that is tapped, rather than separate primary and secondary windings
What is the main advantage of an auto-transformer over a regular transformer mentioned in the text?
Auto-transformers provide more flexibility in adjusting the output voltage
Test your knowledge on filter selectivity and the characteristics of low pass and high pass filters. Learn about the challenges in achieving ideal filter responses and the trade-offs involved in practical filter designs.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
