Design a Tuned RF Amplifier with Gain 100 for 720KHz

AI Thread Summary
Designing a tuned RF amplifier with a gain of 100 at 720KHz using a single BJT presents significant challenges, particularly in achieving the required gain without cascading stages. The use of an LC tank circuit is essential for frequency tuning, but high gain in a single stage is difficult to attain. Recommendations include studying common-emitter amplifier configurations to understand how to maximize gain, while also considering practical aspects like coil size and quality factor (Q). A suggested inductor value is 1 mHy, with a target transistor current of around 9 mA. Achieving this design may yield a functional but not optimal amplifier in practical applications.
i_m_sadiq
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Hey...I was trying to design a practical of mine...There is this question where I am supposed to design a tuned RF Amplifier with gain 100 for a frequency 720KHz with BJT. I know that I will get frequency with LC tank circuit but the gain is a different story. I have searched 5-6 books and am yet to find a correct design procedure for such an RF amplifier.

How's is this designing done??...Or atleast can someone point me towards the place where I can find the design??

Thanks
 
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i_m_sadiq said:
Hey...I was trying to design a practical of mine...There is this question where I am supposed to design a tuned RF Amplifier with gain 100 for a frequency 720KHz with BJT. I know that I will get frequency with LC tank circuit but the gain is a different story. I have searched 5-6 books and am yet to find a correct design procedure for such an RF amplifier.

How's is this designing done??...Or atleast can someone point me towards the place where I can find the design??

Thanks

Are you supposed to get that gain with just one BJT, or can you cascade two stages?

Wikipedia has some pretty good introductory pages on transistor amplifiers. See the "Radio" section of this page for example:

http://en.wikipedia.org/wiki/Common_emitter

:smile:
 
It has to be single staged amplifier...
 
i_m_sadiq said:
It has to be single staged amplifier...

That's not going to be easy, depending on the signal amplitude that you have to work with. Do some reading about common-emitter amplifiers, especially how to get high gain out of them.
 
I think it's barely doable, not a good design but it might work in the lab. Consider L = 1 mHy for the coil. Might be a pretty large-volume coil to get a Q of at least 20. Run the transistor around 9 mA.
 
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