Deck 27: Filters

Question 1

The ability of any filter to reduce the amplitude of undesired frequencies is called ______________ of the filter.

Answer 1

attenuation

Question 2

A(n) ______________ filter uses an operational amplifier on an IC chip.

Answer 2

active

Question 3

The ______________ filter passes to the load all frequencies higher than the cutoff frequency.

Answer 3

high-pass

Question 4

Any low-pass or high-pass filter can be thought of as a ______________-dependant voltage divider.

Question 5

The ______________ filter is comprised of a high-pass and low-pass filter in order to pass only a certain band of frequencies.

Question 6

A band-stop filter is also called a ______________ filter.

Question 7

In analyzing filters, the ______________ unit is often used to describe the amount of attenuation offered by the filter.

Question 8

The frequency ______________ of a filter is typically shown by plotting its gain or loss versus frequency on logarithmic graph paper.

Question 9

______________ circuits provide a convenient method of filtering a band of radio frequencies because relatively small values of L and C are required for resonance.

Question 10

In the application of a band-stop filter to suppress certain frequencies, the LC circuit is often called a ______________.

Question 11

A filter that allows the higher frequency components of the applied voltage to develop voltage across the output load resistance is a

A) low-pass filter
B) high-pass filter
C) band-pass filter
D) band-stop filter

Question 12

Which of the following is not a common type LC filter?

A) L
B) T
C) H
D) p

Question 13

The ability of any filter to reduce the amplitude of undesired frequencies is called

A) attrition
B) skirting
C) attenuation
D) amplification

Question 14

The frequency at which the attenuation reduces the output to 70.7% is the

A) fundamental frequency
B) harmonic frequency
C) resonant frequency
D) cutoff frequency

Question 15

What type filter passes to the load all frequencies higher than the cut-off frequency?

A) Low-pass filter
B) High-pass filter
C) Band-pass filter
D) Band-stop filter

Question 16

With a high-pass filter, the output

A) is taken across the capacitor
B) is taken across the resistor
C) is comprised of frequencies below f_c
D) will pass 0 Hz

Question 17

What type filter uses a high-pass filter combined with a low-pass filter in order to pass only a certain band of frequencies?

A) Low-pass filter
B) High-pass filter
C) Band-pass filter
D) Band-stop filter

Question 18

What type filter uses a high-pass filter combined with a low-pass filter in order to block or severely attenuate a certain band of frequencies?

A) Low-pass filter
B) High-pass filter
C) Band-pass filter
D) Band-stop filter

Question 19

With a band-stop filter, the frequency of maximum attenuation is called the

A) fundamental frequency
B) harmonic frequency
C) notch frequency
D) resonant frequency

Question 20

A logarithmic expression that compares two power levels is the

A) power factor
B) coefficient of coupling
C) Q
D) decibel

Question 21

A reduction in power, corresponding to a loss in decibels is referred to as

A) attrition
B) attenuation
C) reduction
D) scaling

Question 22

What is shown by plotting gain or loss versus frequency on logarithmic graph paper?

A) Resonant frequency
B) Power factor
C) Frequency response curve
D) Transistor collector curve

Question 23

What is the rolloff rate for an RC low-pass filter below the cutoff frequency?

A) 1 dB/octave
B) 12 dB/octave
C) 4 dB/octave
D) 40 dB/octave

Question 24

What circuits provide a convenient method of filtering a band of radio frequencies because relatively small values of L and C are necessary for resonance?

A) Oscillators
B) Magnetic
C) Tuned
D) Bridge

Question 25

In the application of a band-stop filter to suppress certain frequencies, the LC circuit is often called a

A) waveshaper
B) wavetrap
C) wavestop
D) waveblock

Question 26

What is the characteristic of some crystals that causes them to vibrate by a voltage input or produce voltage output when compressed, expanded, or twisted?

A) Conductivity
B) Resonance
C) Piezoelectricity
D) Harmonics

Question 27

Current that varies in amplitude but does not reverse in polarity is considered

A) fluctuating dc
B) fluctuating ac
C) pulsating ac
D) steady dc

Question 28

Which of the following components is used to isolate or block a steady dc?

A) Inductor
B) Transformer
C) Capacitor
D) Resistor

Question 29

Just about the most common type coupling in amplifier circuits is

A) capacitive
B) direct
C) transformer
D) impedance

Question 30

The size of a coupling capacitor depends on the

A) voltage level of the power supply
B) value of capacitance
C) frequency of the ac component
D) type of amplifier

Question 31

With an ideal filter, what attenuation should exist within the passband?

A) Infinite
B) Zero
C) 100 k?
D) 10 M?

Question 32

An electrical filter can separate different frequency components.

Question 33

Generally, inductors and capacitors are not used for filtering because of their opposite frequency characteristics.

Question 34

The amount of attenuation offered by a filter is usually specified in decibels.

Question 35

The ac signal voltages present at the input to a filter usually span a wide range of frequencies.

Question 36

For audio mixed with radio frequencies, a low-pass filter allows the audio frequencies in the output.

Question 37

Current that varies in amplitude but does not reverse in polarity is considered ac.

Question 38

The ac component of a fluctuating dc waveform is called ripple.

Question 39

A transformer with a separate secondary winding isolates or blocks steady direct current in the primary.

Question 40

Capacitive coupling is probably the most common type of coupling in amplifier circuits.

Question 41

The coupling capacitor isolates the dc voltages in each stage while still coupling the ac signal.

Question 42

The size of a coupling capacitor depends on the power supply being used in the amplifier circuit.

Question 43

Inductors are often used in parallel with resistance to bypass the ac component of a pulsating dc voltage.

Question 44

A coupling capacitor couples the ac signal to R and the shunt bypass capacitor short-circuits R for the ac signal.

Question 45

A low-pass filter allows the lower frequency components of the applied voltage to develop output voltage across the load resistance.

Question 46

An ideal filter would offer infinite attenuation within the passband and zero attenuation throughout the stop band.