# Circuit analysis

enter image description here I don’t understand what is the Use of ‘Vin’ as its anode connects to the open circuit.So I can’t even solve QA

• If vIN is a sine wave, it will vA is a sinewave equal to vIN. Which can be applied to current source as long as it meets restraints. It is a FET amplifier, which works on voltage. Sep 10 '21 at 16:04
• This is a simplified mathematical model of a real circuit. See that no current flows through the open circuit VA, BUT the current through the current source depends on the voltage across the open circuit VA! Sep 10 '21 at 16:35
• This is not a circuit made from "real" components. It shows a mathematical description of what the real amplifier does. The math equations show how the Vout depends on Va, and in the left hand diagram Vin = Va. Sep 10 '21 at 19:06
• what is the Use of ‘Vout’ as its anode connects to the open circuit.So I can’t even solve QA. Same with Vin. it's there to just say sample this in a manner where current is 0
– Abel
Sep 11 '21 at 3:09
• We won't do your homework for you. If you still don't understand how to begin a problem like this you should talk to your instructor. Sep 11 '21 at 12:21