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JFET buffer utput impedance?

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neazoi

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Hi I was wondering what is the component that defines primarily the output impedance in this jfet buffer HF amplifier?
 

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Can I leave this choke out for a broadband (HF) jfet buffer?
Yes, but then the source resistor forms a voltage divider with the FET buffer output impedance.
 
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    neazoi

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Yes, but then the source resistor forms a voltage divider with the FET buffer output impedance.

So the RF output voltage will be lower than the input then, despite this is a gain 1 buffer...
Correct me if I am wrong.
Thanks a lot!
 

Yes common drain buffer has always a gain below unity, only with high load impedance and high source resistor (or current source bias) it can achieve near unity gain.
 
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