I am trying to work out the BW of my transformer

In summary: Hello, chedor. I'm new to transformers, and I'm trying to understand the basics of how they work. I've read the introduction to transformers on Wikipedia, but I'm still a little confused about how the calculations in that article relate to real-world transformers. Can you help me understand that better?In summary, the article suggests that to find the lower -3dB point, you refer the secondary load to the primary. This gives RL'=50R. To find the upper -3dB point, you add the total resistance, Rs + RL'.
  • #1
KennyB
1
0
I am trying to work out the BW of my transformer.


My source resistance, Rs, is 50R. My load resistance, RL=50R. The windings ratio ,N, is 1:1. The magnetising current, Lmag=7.96uH. The data i have suggests that to find the lower -3dB point, you refer the secondary load to the primary. This gives RL'=50R. In order to find the cut off point, the resistance of the primary is equated to the reactance of Lmag. The combined resistance is defined as Rs//RL'= 50R//50R = 25R. The lower cut-off is then evaluated as 500KHz. A little confused by this because although the leakage inductances are essentially shorts at this frequency, Lmag appears in // with the primary referred load, RL'...and these two components combined are in // with Rs. Unsure.

Now for the upper -3dBpoint...the data now says that the total resistance is Rs + RL'. Why is Thevenin's not applicable here?! The primary winding leakage inductance equals the secondary winding leakage inductance = (1-K)*Lmag where K = 0.998333. The upper -3dB point was evaluated as 600MHz.

Can somebody please clear this up for me?

PS: The reason why I'm interested in the maths of this is that i want to input this data into SIMetrix for analysis with additional analogue front-end circuitry.
 
Last edited:
Engineering news on Phys.org
  • #2


There will be stray capacitance involved at 600MHz which may produces resonances. I wouldn't expect the attenuation/frequency curve to be smooth. There might be frequencies where the attenuation becames very high..deep nulls. Any core material will behave differently at UHF compared to LF. There will be so many unknowns that it will be impossible to calculate. The only way is measurement of a real transformer. Even then terminations and even short lengths of coax will distort the results.

If you consider it as a purely (ideal) mathematical exercise that is a different thing.
 
  • #3


helo pro Engs.

I am new here i will like to know more of this transformer calculation .i intend to be faithful explain to ,i am expecting thing of fabulous ...


Thanks
rasheed
 
  • #4


chedor said:
helo pro Engs.

I am new here i will like to know more of this transformer calculation .i intend to be faithful explain to ,i am expecting thing of fabulous ...


Thanks
rasheed

Welcome to the PF, chedor. What is your background so far with transformers? Have you read the introduction to transformers at wikipedia.org yet? If you have specific questions, you could start a new thread here (or in the Homework Help forums if your questions are for schoolwork), and list your specific questions.
 
  • #5


thanks for early reply...i am new in the field but i have faith that with time i will be a profeesional ,the you have email.. that we can dicus better that this..i have little idea of transformer ..

thanks
rasheed
 

1. What is BW and why is it important for transformers?

BW, or bandwidth, is a measure of the frequency range over which a transformer can effectively transfer energy. It is important because it determines the transformer's ability to handle different frequencies and signals without distortion.

2. How do I calculate the BW of my transformer?

The BW of a transformer can be calculated by dividing the -3dB frequency by the center frequency. The -3dB frequency is the point at which the power output drops to half of the maximum power output. The center frequency is the frequency at which the transformer is designed to operate.

3. What factors affect the BW of a transformer?

The BW of a transformer is affected by several factors such as the number of windings, the core material, and the physical design of the transformer. The type of signal being transferred and the load impedance can also impact the BW.

4. How does the BW of a transformer relate to its efficiency?

A transformer with a wider BW will generally have a higher efficiency, as it can effectively transfer a wider range of frequencies. This means that the transformer can handle a variety of signals and loads without significant loss of energy.

5. Can the BW of a transformer be increased?

Yes, the BW of a transformer can be increased by using a higher quality core material, optimizing the design, and adding additional windings. However, increasing the BW may also result in a decrease in other performance factors, such as efficiency and size.

Similar threads

  • Electrical Engineering
Replies
8
Views
916
Replies
64
Views
5K
  • Electrical Engineering
Replies
2
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
11
Views
3K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
7K
Back
Top