What should be the Zin for the common source JFET amplifier ?

[ahmed osama]

Dear all

can any one tell me in an exact way what is the Zin for the common source JFET amplifier should be ??

i searched the net and i found it should be only Cap. impedance ?

kindly check the simulation reault , i should see the real part of Zin about 1 Mohm?

but the reault so low !!

can any one explain what is the problem ? what is the wrong thing here ??

thanks

bye

 

[shwoo]

Re: strange Zin ???

The gate of a JFET will not behave as an open circuit at 100MHz.
Check the data sheet of the device.
S. H.

 

[ahmed osama]

Re: strange Zin ???

The gate of a JFET will not behave as an open circuit at 100MHz.
Check the data sheet of the device.
S. H.

yes i know but i should see the Zin almost Cap. but no resistance (i should see 1 Mohm because the resistor)

thanks

bye