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Technical issues related to RF transistor SD2933:We want to use this transistor to drive piezoelectr

H_YM
Associate II

I have the following questions and need help:

1. Can this transistor be used at a frequency of 900kHz? Can it only be used in frequency bands above 1MHz?

2. The data sheet provides a test circuit under 30MHz conditions. We do not fully understand the functions and principles of the FB2 and T2 components. Can you explain it to us? We guess that the function of this component should be for impedance conversion. Can the FB2 and T2 components be replaced with a simple and easy-to-understand transformer impedance conversion form (FT-43 core) like the previous stage?

3. Is the output of the 30MHz test circuit given by the data sheet sine wave? L1, L2 should play a low-pass filter, but I see its winding method did not understand, can you explain?

4. We want to imitate the 30MHz test circuit and apply it directly to the production environment. Are there any other issues worth noting during this process?

14 REPLIES 14

Thank you for giving me such valuable advice
I think the ready-made magnification module you provided me is a good learning material. However, because I am located in China, I cannot search similar products and websites through my browser, so I would like to ask if it is convenient for you to recommend several similar products and purchase websites.
Your recommended learning path:It's a great idea to start with low power and keep trying and experimenting. I will strive to be as good an expert as you.

 

Thank you for the flowers .

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Is your piezo something like this:

AScha3_0-1713876410001.png

or this:

AScha3_2-1713878028137.png

 

(from Ali express , you should find it more easy than me...)

And there is the driver inside, maybe 10W  max. ; but i would guess, interesting to learn how they do.

https://de.aliexpress.com/item/1005005859729805.html

AScha3_1-1713877040378.png

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For learning how to build and what will work; i recommend most: learn + use a simulation program first !

I use one of the best - and its free : LTspice -> 

https://www.analog.com/en/resources/design-tools-and-calculators/ltspice-simulator.html

After some training (see the tutorials..) you can try a circuit, see whats not good, modify - until it works as you want; 

then build it real (and if your simulation was close enough to reality) it will work . Without killing a lot of parts.

And if you have questions, write me a PM .

If you feel a post has answered your question, please click "Accept as Solution".

The shape of the ultrasonic is as follows:

8666970a6195122e9d9e64a223f657a.jpg

It is timely for you to recommend this software to me. I just realize that I need a good circuit design software to help me learn, and I will spend time to study this software carefully

I hope you can recommend me more books or good learning methods about transistor circuit design

For learning about - electronics - this was my most important book:

AScha3_0-1713888520299.png

(I bought as real book that time, still have it...) 

https://archive.org/details/the-art-of-electronics-3rd-ed-2015_202008

https://pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_16/Sec_51/4420_The_Art_of_Electronics.pdf

 

If you feel a post has answered your question, please click "Accept as Solution".

Thank you for your recommendation. I will read this book carefully.