Passive Filters (Electrical Engineering mcq)
1. In a series resonant band-pass filter, a lower value of Q results in
a larger bandwidth.
2. The function of a bleeder resistor in a power supply is
to ensure a minimum current drain in the circuit.
3. The primary function of filter is to
remove ripples from the rectifier output.
4. The roll-off rate of a basic RC or RL filter is
20 dB per decade.
5. In an RL high-pass filter, the output is taken across the inductor and the output
leads the input.
6. Critical frequencies are also called –
3 dB frequencies.
Note: - It is sometimes taken to be the point in the filter response where a transition band and passband meet, for example, as defined by a half-power point (a frequency for which the output of the circuit is −3 dB of the nominal passband value).
7. The bandwidth of a resonant filter is determined by the quality factor (Q) of the circuit and the
resonant frequency.
Note: - In physics, resonance is a phenomenon in which a vibrating system or external force drives another system to oscillate with greater amplitude at specific frequencies.
8. In a certain low-pass filter, fc = 3.5 kHz. Its pass-band is
0 Hz to 3.5 kHz
Note: - A low-pass filter (LPF) is a filter that passes signals with a frequency lower than a certain cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency. The filter is sometimes called a high-cut filter, or treble-cut filter in audio applications.
9. At a certain frequency, the output voltage of a filter is 6 V and the input is 12 V. The voltage ratio in decibels is
-6.02 dB
Mcq on Active Filters – 1
10.Which filter type is called a flat-flat filter?
Butterworth filter.
Note: -
The key characteristic of the Butterworth filter is that it has a flat pass band as well as stop band. So, it is occasionally called a flat-flat filter.
11. In which filter the output and input voltages are equal in amplitude for all frequencies?
All-pass filter.
Note: -
In all-pass filter, the output and input voltages are equal in amplitude for all frequencies.
12. The gain of the first order low pass filter
Decreases at the rate 20dB/decade.
Note: -
The rate at which the gain of the filter changes in the stop band is determined by the order of filter.
13. Determine the order of filter used, when the gain increases at the rate of 60dB/decade on the stop band.
Third-order High pass filter.
14. Name the filter that has two stop bands?
Band-pass filter.
Note: - A bandpass filter is an electronic device or circuit that allows signals between two specific frequencies to pass, but that discriminates against signals at other frequencies. The range of frequencies between f1 and f2is called the filter passband.
15. An electrical filter is a
Frequency-selective circuit.
Note: -
An electric filter is often a frequency selective circuit that passes a definite band of frequencies and blocks or alternates signal of frequencies outside this band.
16. Filters are classified as
Analog or digital
Audio or radio frequency
Passive or active
All the mentioned
Note: - Filters are classified based on the design technique (analog or digital), elements used for construction (active or passive) and functioning range (audio or radio frequency).
17. Why inductors are not preferred for audio frequency?
Large and heavy.
18. The problem of passive filters is overcome by using
Active filter.
Note: - The active filters enclose as a capacitor in the feedback loop and avoid using inductors, this way inductor less active filter is obtained.
19. A band pass filter is one which
passes frequencies between two designated cut-offs frequencies and attenuates all other frequencies.
20. An ideal filter is one which
zero attenuates in the pass band.
21. In the m-derived low pass filters, the resonant frequency is to be chosen so that is
above the cut-off frequency.
22. A band elimination filter is one
frequencies lying between f1 and f2 are attenuated and all other frequencies are passed.
23. A 10 V power supply would use electrolytic capacitor as
filter capacitor.
Note: -
An electrolytic capacitor is a type of capacitor that uses an electrolyte to achieve a larger capacitance than other capacitor types. Almost all electrolytic capacitors are polarized, which means that the voltage on the positive terminal must always be greater than the voltage on the negative terminal.
24. A 1000 V power supply would use paper capacitor as a
filter capacitor.
25. The choke input filter circuit results in the best
voltage regulation.
26. A low pass filter is one which
passes all frequencies up to cut-off frequency and attenuates all other frequencies.
27. A high pass filter is one which
attenuates all frequencies below a designated cut-off frequency and passes all frequencies above cut-off.
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