2022/2023
Al-Quds University
Faculty of Engineering
Electronic Engineering Dept.
Prepared By:
Hamza Damra
Student ID:
Electric Circuits Laboratory
Lab experiment #7
𝑭𝒊𝒍𝒕𝒆𝒓𝒔
Instructor:
Date: 03/22/2022
Dr. Amjad
2011319
Contents :
7.1 Introduction………………………………………………....3
7.2 Procedure and discussion.……...…………..…………..........3
7.3 Conclusion…………………………………………………..8
Table of Figures
7.1
LC Low-Pass Filter circuits…………………………...….…………………..………....….....3
7.2
Circuit #1……………………………………….………………………………….……….....3
7.3
LC High-Pass Filter circuits…………………………...….…………...……..………....….....5
7.4
Circuit #2……………………………………….………………………………….……….....5
7.5
Band-Stop (Notch) RC Filter circuit………………….……….......................................….....6
7.6
Circuit #3……………………………………….………………………………….……….....7
7.1 Introduction :
We learned in some previous experiments about filters and we knew that filters
are four types; Low-Pass Filter (LPF) , High-Pass Filter (HPF) , Band-Pass Filter
(BPF) and Band-Stop Filter (BSF) , and we learned some of their configurations.
However, there are more about filters configuration and we will just learn new
configurations in this experiment.
7.2 Procedure and discussion :
7.2.1 𝑷𝒂𝒓𝒕 𝑨 ∶ 𝐿𝐶 𝐿𝑜𝑤 − 𝑃𝑎𝑠𝑠 𝐹𝑖𝑙𝑡𝑒𝑟:
There are two types of this filter configuration:
Figure 1
𝐿=
𝑍𝑜
𝜋𝑓𝑐
[𝐻]
𝐶=
1
𝜋𝑍𝑜 𝑓𝑐
[F]
𝑓𝑐 =
1
𝜋√𝐿𝐶
[Hz]
We connect the following circuit and record the outputs as follow :
3
Figure 2
𝐿
𝑍𝑜 = √ [Ω]
𝐶
We will apply sinusoidal signal 𝑉𝑖 with 1𝑉𝑝 and 1𝑘𝐻𝑧 frequency.
If we change the frequency and measure the value of 𝑉𝑖 and 𝑉𝑜 , we will get
the following table :
Frequency [kHz]
|𝑉𝑖 | [V]
|𝑉𝑜 | [V]
Gain = |𝑉𝑜 |⁄|𝑉𝑖 |
1
1
0.95
0.95
3
1
0.85
0.85
5
1
0.75
0.75
7
1
0.6
0.6
10
1
0.34
0.34
20
1
0.095
0.095
40
1
0.018
0.018
If we plot our data in the table above, we will get :
From the last graph, we notice that we get a good low-pass filter.
𝑓𝑐 =
4
1
𝜋√𝐿𝐶
= 10.0658 𝑘𝐻𝑧 , and we can see that clearly in our graph.
100
1
0.002
0.002
7.2.2 𝑷𝒂𝒓𝒕 𝑩 ∶ 𝐿𝐶 𝐻𝑖𝑔ℎ − 𝑃𝑎𝑠𝑠 𝐹𝑖𝑙𝑡𝑒𝑟:
There are two types of this filter configuration:
Figure 3
𝐿=
𝑍𝑜
4𝜋𝑓𝑐
[𝐻]
𝐶=
1
4𝜋𝑍𝑜 𝑓𝑐
𝑓𝑐 =
[F]
1
4𝜋√𝐿𝐶
𝐿
𝑍𝑜 = √ [Ω]
[Hz]
𝐶
We connect the following circuit and record the outputs as follow :
Figure 4
We will apply sinusoidal signal 𝑉𝑖 with 1𝑉𝑝 and 1𝑘𝐻𝑧 frequency.
If we change the frequency and measure the value of 𝑉𝑖 and 𝑉𝑜 , we will get
the following table :
Frequency [kHz]
|𝑉𝑖 | [V]
|𝑉𝑜 | [V]
Gain = |𝑉𝑜 |⁄|𝑉𝑖 |
5
1
1
0
0
3
1
0.058
0.058
5
1
0.2
0.2
7
1
0.7
0.6
10
1
0.9
0.9
20
1
1
1
40
1
1
1
100
1
1
1
If we plot our data in the table above, we will get :
From the last graph, we notice that we get a good high-pass filter.
𝑓𝑐 =
1
4𝜋√𝐿𝐶
= 5.3651 𝑘𝐻𝑧 , and we can see that clearly in our graph.
7.2.3 𝑷𝒂𝒓𝒕 𝑪 ∶ 𝐵𝑎𝑛𝑑 − 𝑆𝑡𝑜𝑝 (𝑁𝑜𝑡𝑐ℎ) 𝑅𝐶 𝐹𝑖𝑙𝑡𝑒𝑟:
We knew previously how we get a band-pass filter circuit, but how
does the band-stop filter circuit look like ? It is seem like this:
Figure 5
6
𝑓𝑐 =
1
2𝜋𝑅𝐶
[Hz]
We connect the following circuit and record the outputs as follow :
Figure 6
We will apply sinusoidal signal 𝑉𝑖 with 1𝑉𝑟𝑚𝑠 and 200𝐻𝑧 frequency.
If we change the frequency and measure the value of 𝑉𝑖 and 𝑉𝑜 , we will get
the following table :
Frequency [Hz]
|𝑉𝑖 | [Vrms]
|𝑉𝑜 | [Vrms]
Gain= |𝑉𝑜 |⁄|𝑉𝑖 |
200
1
0.72
0.72
400
1
0.427
0.427
600
1
0.247
0.247
800
1
0.147
0.147
1000
1
0.131
0.131
1200
1
0.173
0.173
If we plot our data in the table above, we will get :
7
1400
1
0.231
0.231
1600
1
0.288
0.288
1800
1
0.339
0.339
2000
1
0.387
0.387
From the last graph, we notice that we get a good band-stop filter, BUT we
notice that the curve increasing at a pace less than decreasing.
𝑓𝑐 =
1
2𝜋𝑅𝐶
= 795.775 𝐻𝑧 , and we got a result close to this answer through the
graph above.
7.3 Conclusion :
References:
8