Why in a FET the source at RF is always grounded?

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ssayan79

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Hi
I'm a studentin electronic enginner and i have a problem.
I' ' d like to know why in a fet the source, at rf, is always grounded, like the emitter in a bjt.
Thanks
 

Re: Source grounded

This isn't always the case. This source(emitter) grounding is in any circuit to operate as an amplifier, as adding a resistance there would degenerate the gain of the amplifier. In RF we usually use active devices for gain, so we keep the source(emitter) grounded. If you were making an oscillator, you'ld use an impedance there.
 

Re: Source grounded

thanks a lot for the reply. can you indicate a book where this concept is explained clearly?
 

Re: Source grounded

Hi,
It's not the typical case to find the source or the emitter is tied to ground in RF, but may be you chose a device which is connected to its bulk tie
Am I right ?
best regards,
Rania
 

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