a) In which mode of operation is a FET used for an amplifier? (Cut-off, Saturation, Active, Passive, Triode, or Pentode) (1 mark) b) A depletion FET is an attractive choice for a DC-coupled voltage amplifier. Why? (1 mark) Vo Ra التي WH R Vove Figure Q5 c) Consider the N-channel MOSFET amplifier given in Figure Q5. ips=(Vas-V+)², VDD=5V, RL=2k, K=1mA/V2, V₁ = IV. You can ignore ra of the MOSFET. Cc is the input coupling capacitor. You can assume it is infinitely large. Derive an expression for the transistor bias point Vaso as a function of VDD, R, and Rb- (3 marks) i. ii. Determine the required ratio R./R, such that the MOSFET gm=1mA/V. whereas g is defined as alps (8 marks) iv. What is the voltage bias point of the output Vouto? (If you cannot calculate a numerical answer leave the answer it in terms of the given circuit parameter values, R, and R.). Use the results from part(ii). (4 marks) Draw the small-signal model for the amplifier and calculate the gain Vout/Vin- Clearly label the component values and small-signal voltages Vin and Vout- Use the results from part(ii). (3 marks)