17.6. Transfer Characteristics and Gain

Try these first

1. 1.

   Define gain in the context of MOSFET circuits.

   Hint

   Think about how we measure the effectiveness of amplification.

2. 2.

   What is the saturation region in MOSFET operation?

   Hint

   Consider what happens when the MOSFET is fully turned on.

3. 3.

   What does the transfer characteristic curve represent in a MOSFET?

   • A. Input voltage only
   • B. The relationship between input and output voltages
   • indicating amplification
   • C. Only the output voltage

   Hint

   Think about what each axis of the graph represents.

4. 4.

   True or False: The saturation region of a MOSFET is where it behaves like a variable resistor.

   • True
   • False

   Hint

   Consider how current flows when the MOSFET is fully on.

5. 5.

   A MOSFET has K = 3 mA/V², V_th = 1.5 V, and operates with V_in = 4.5 V. Determine if it operates in saturation or triode when connected to a load of R_D = 1 kΩ. Calculate the gain at this point.

   Hint

   Check the condition V_DS > V_GS - V_th to verify saturation.

6. 6.

   Design a MOSFET amplifier circuit needing an output current of 5 mA at a voltage gain of 10. Given K = 4 mA/V², determine load resistance and the necessary input voltage to achieve the desired performance.

   Hint

   Use the relationships between gain, current, and resistance to find required values.