Electronics > Beginners

Feedback on transistors

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chagli:
Hi,
I am building a low-power FM transmitter based on a pre-existing design.
The first stage is a simple discrete audio amplifier consisting of one NPN transistor (see attached picture).
I would like to understand and adapt it.
I think I have the minimum education concerning bipolar transistors (Ebers and Hybrid-Pi models).
But I am not very familiar with feedback on transistor level. I often see some qualitative statements concerning the effects but no rigorous development.
Could you recommend me a book which addresses feedback at transistor level ?
Thank you.

ferdieCX:
This circuit has only DC feedback.
You will find the basic circuit discussed in chapter 10 of "Electronic Devices and Circuits" by Millman and Halkias

https://archive.org/details/ElectronicDevicesCircuits/page/n142

Feedback is discussed in chapter 17

chagli:
Hi,
Thanks for your answer I will look at the reference.
I think the capacitor C2 is a way to apply pre-emphasis to the audio signal by lowering the feedback at higher frequencies (thus increasing the gain).

ferdieCX:
You are probably right. The feedback is high at 20 Hz and very low at 15 KHz

newbrain:
Note that the symbol for the transistor is wrong!

It should have the arrow pointing out (NPN) not in (PNP).

The 2N3565 is, in fact, an NPN transistor.

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