Why Isn't the Drain Voltage in a MOSFET Circuit Equal to 1.8V?

[CoolDude420]

Homework Statement

Homework Equations

The Attempt at a Solution

We have been given this question along with some parameters.
It asks for find drain votltage, my question is why isn't the drain voltage just equal to 1.8? I mean the resistor should be getting the entire 1.8V so?

 

[gneill]

We have been given this question along with some parameters.
It asks for find drain votltage, my question is why isn't the drain voltage just equal to 1.8? I mean the resistor should be getting the entire 1.8V so?

It would be 1.8 V if the FET were cut off (completely non-conducting). Do you have reason to believe that this is the case?

 

[CoolDude420]

It would be 1.8 V if the FET were cut off (completely non-conducting). Do you have reason to believe that this is the case?

no. Ah, I keep considering the branches of the terminals of the MOSFET independent due to the gap in the circuit diagram of it. So basically because of the gate terminal I can't just assume its 1.8V

 

[gneill]

no. Ah, I keep considering the branches of the terminals of the MOSFET independent due to the gap in the circuit diagram of it. So basically because of the gate terminal I can't just assume its 1.8V

Schematic diagram symbols often offer a stylized hint as to the underlying construction of the components they represent, but really they can't do more than jog your memory about how they actually function.

You hinted at being given some parameters. You'll have to use them to work out what operating mode the FET is in and then find its DC operating point.

 

[rude man]

It asks for find drain votltage, my question is why isn't the drain voltage just equal to 1.8? I mean the resistor should be getting the entire 1.8V so?

You're contradicting yourself here.