CS-MOSFET amplifier: why is hardware gain -40 to -45 instead of -11.3?

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pforpashya
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Hi all,

I am studying cs_mosfet amplifier and i have simulate one simple amplifier with VDD=+12v Vs=1v ID=0.5mA gm=1mA/v Vd=6v. I am getting a signal that is amplified by gain -11.3 by calculation and also on simulation but when doing on hardware i am getting gain around -40 to -45
I am using Bs 170 mosfet.

I have tried various combination of capacitors but still gain comes around -40...can anybody suggest me where is the mistake?
 
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How can you be sure that your real MOSFET Bs170 will indeed have gm = 1m?
Do know how to measure Vgs(th) and how you can find K - factor ?

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Can you verify you are using the correct transistor?

Can you verify you are using the correct resistor?

Have you verified the DC operating point?