How to do the DC analysis or get the kn*W/L value?

[johnchau123]

DC analysis

I have a question which requires me to do DC analysis. But I don't know how to do since I cannot get the value kn*W/L.
I am not sure if there are other techniques which can help to solve the question.
The circuit is as follows.





Thanks.

 

[Guachuchon]

Re: DC analysis

For DC analisys you must remember that the capacitors don't permit circulation of DC current. Therefore you must erase the parts of circuit that contain capacitors.

Solve the problem considering the condensors are a Resistancen with infinity value

You must calculate ID with the Transistor's equation and doing the KVL with RG2, RS and VGS

After that you must calculate voltages in each part of the transistor. Remember that voltage in the Gate is the same that in RG2


Remember that this is only for DC analisys

If you need comprobate it you can use a Spice software, I recommend you Microcap because is very easy to use

 

[johnchau123]

Re: DC analysis

I know how to do do the questions.

The value k*W/L need not be used in the question.

I use the formula ID = IDSS×(1-VGS/Vp)², where VGS = 6-3.5ID. After solving the quadratic equation, I gor ID=0.2mA.