A band pass filter allows signals between two specific frequencies to pass through, while blocking signals of other frequencies. To create a passive band pass filter, a low pass filter is connected in series with a high pass filter. This passes a selected range of frequencies while attenuating frequencies outside this range. In this project, the student designs a passive band pass filter with cutoff frequencies of 19 kHz and 39 kHz by using resistors R1 of 83 ohms and R2 of 500 ohms, along with capacitors C1 and C2 both of 0.01 microfarads. The student then tests the filter on different frequencies and charts the output voltages to analyze the filter's performance.

1. Names ( IDs )
Project
Report
To Ma’am/Sir
Sh***l
Department of Electrical and Computer Engineering

2. PASSIVE BAND PASS RLC CIRCUIT
(Low pass and high pass circuits)
OBJECTIVE
The objective of this complex engineering problem is to
investigate and design a practical problem
that has following attributes:
❖ The activity requires abstract thinking, originality in analysis to
formulate suitable software and hardware models of the activity.
❖ The activity involves creative use of engineering principles and
research-based knowledge in novel ways.
What is Passive band pass filter?
A band pass filter is an electronic device or circuit that
allows signals between two specific frequencies to pass, but that
discriminates against signals at all other frequencies.
Band Pass Filters can be used to isolate or filter out certain frequencies
that lie within a particular band or range of frequencies. The cut-off
frequency or ƒc point in a simple RC passive filter can be accurately
controlled using just a single resistor in series with a non-polarized capacitor,
and depending upon which way around they are connected, we have seen that
either a Low Pass or a High Pass filter is obtained.
How to make a Passive band pass filter?
By connecting or “cascading” together a single Low Pass Filter circuit
with a High Pass Filter circuit, we can produce another type of passive RC
filter that passes a selected range or “band” of frequencies that can be either
narrow or wide while attenuating all those outside of this range.
This new type of passive filter arrangement produces a frequency selective
filter known commonly as a Band Pass Filter or BPF for short.

3. For R1
Formulas used to calculate values
R1= 1/2 (3.1416) (fc)(C)
R1=1/2 (3.14) (19*103
) (0.01*10-6
)
R1=83 ohm
For R2
R2= 1/2 (3.1416) (fc) (C)
R2= 1/2 (3.1416) (39*103
) (0.01*10-6
)
R2= 500 ohm
Points to ponder while choosing cut off frequency and resistors
❖ High Pass Filter’s cut-off frequency should be equal to Last two
digits of your
registration number (in KHz).
❖ Low Pass Filter’s cut-off frequency should be equal to sum of last
two digits of your registration number plus 20 KHz.
❖ Calculate the specific values of Resistors and Capacitors for both
filters separately.
❖ Make a table of frequencies and Vo for at least 30 values of
frequencies and make a graph of Frequencies vs Vo using the
values of the table.
❖ Use AC sweep option and generate a graph of frequency vs Vo.

4. Table of calculated values on different frequencies
Voltages Frequencies V0 Vm
(V) (Hz) Output voltage V0*0.707
10 V 90 Hz 0 0
10 V 100 Hz 0 0
10 V 150 Hz 0 0
10 V 200 Hz 0 0
10 V 300 Hz 0.2 0.14
10 V 600 Hz 0.3 0.21
10 V 1000 Hz 0.4 0.28
10 V 1500 Hz 0.4 0.28
10 V 2500 Hz 0.6 0.42
10 V 3500 Hz 0.8 0.56
10 V 5k Hz 1.2 0.84
10 V 8K Hz 2 1.41
10 V 10K Hz 2.4 1.69
10 V 30K Hz 4.8 1.69
10 V 50K Hz 5.6 3.39
10 V 80K Hz 5.8 3.9
10 V 90K Hz 5.8 4.1
10 V 100K Hz 5.8 4.1
10 V 110K Hz 5.4 4.1
10 V 200K Hz 4.2 3.8
10 V 300K Hz 3.2 2.9
10 V 400K Hz 2.6 2.26
10 V 500K Hz 2.3 1.83
10 V 800K Hz 1.5 1.62
10 V 1M Hz 1.3 1.06
10 V 2M Hz 0.9 0.91
10 V 8M Hz 0.7 0.63
10 V 10M Hz 0.7 0.49
10 V 12M Hz 1.1 0.7
10 V 15M Hz 1.8 1.27

5. Applications of Bandpass Filter
The bandpass filter has a wide range of applications as mentioned below.
It is used in optics like LIDARS, LASER, etc.
These filters are widely used wireless transmitters and receivers.
In audio signal processing, these bandpass filters play a vital role by
allowing the particular frequencies and removing the unwanted.
These bandpass filters are also used in instruments and applications of
medical and seismology.
One of the best applications of bandpass filters is audio amplifier
circuits. We can observe simply as the speakers will play the desired
range of frequencies and will attenuate the remaining.
The bandpass filter is effectively used in optimizing Signal to Noise
ratio, S/N ratio, and even the sensitivity of the receiver.
As these bandpass filters are specially designed to allow a particular
band of frequencies, so it is widely used in communication systems.
PICTURES OF CIRCUIT ON PSpice(software)
❖ The circuit diagram of the given project is in below image…
 In this diagram, we used…
i. Resistor R1 of 83 ohm.
ii. Capacitor C1 of 0.01uF.
iii. Capacitor C2 of 0.01uF, too.
iv. Resistor R2 of 500 ohm.

6. ❖ The output signal diagram image is in the following below…
1) For this purposes, we’re gonna choose three frequencies
values between f1 and f2 and rest outside the range of f1 and f2
for the table.
2) Select step size 200 Hz.
Conclusion:
By performing this project assessment and seeing the working
of the filter circuit, I learnt that Band-pass filter’s purposes arrangement of
electronic components that allows only those electric waves lying within a
certain range, or band, of frequencies to pass and blocks all other.

7. The End