current series feed back in amplfiers

[bhargava]

Hi,
It is known that a feedback capacitor is used in a CE amplifier in order to avoid current series feed back ie., the drop of input signal across the emitter resistance.Well it is fine up to here But.....
Why do we call the input signal drop across emitter resistance as current series feedback?
I'm struck here some one help me out please.........
Thanks
Bye..........

 

[audioguru2]

Current feedback. Voltage feedback. Series feedback. Parallel feedback. Confusing words.

Why not just call the feedback that is caused by the emitter resistor, emitter resistor feedback?
Then call the feedback caused by a resistor from the collector to the base, collector to base feedback? 

 

[bhargava]

Hi, audioguru!!!,
Well what you said was right but this term"CURRENT SERIES FEEDBACK" is used in many a standard literature on basic amplifiers(by Millman etc...,)I basically understood the phenomenon but couldn't justify the name given to it.

Obviously the name given must be apt and should carry some meaning with it.
To me current series feed back means output current  of an ampbeing collected, given as an input to a feed back ckt(block) whose out put is fed in series with the input but i can't figue out this phenomenon so make the picture clearer to me!!!
Greetings...
Merry Christmas....
Bye...

 

[audioguru2]

I don't care what the feedback is called in books.

Your amp transistor is operating in class-C without any bias current. Its tiny emitter capacitor allows it to amplify only high frequencies. Its load has such a low resistance that its gain is squashed.

 

[audioguru2]

Hi Zeppelin,
A transistor stage without negative feedback has horrible distortion. Its gain is very high but the high distortion makes it unusable and impossible to measure. Here is a circuit with parts values that I simulated:

View attachment 38281

 

[bhargava]

Hi Zepplin,AudioGuru,


Thanks for I've got what i wanted my doubt was clarified thanks for the additinal info provided.

Bhargava