70.4.2. Small Signal Model of Differential Amplifier

Try these first

1. 1.

   Define a differential signal.

   Hint

   Think about how the signal responds based on the comparison of its two inputs.

2. 2.

   What is common mode gain?

   Hint

   Consider how noise affects both inputs similarly.

3. 3.

   What is the primary function of a differential amplifier?

   • To amplify the average of two signals
   • To amplify the difference between two signals
   • To filter noise
   • To square the input signal

   Hint

   Focus on what makes differential amplifiers unique.

4. 4.

   True or False: Common mode signals are undesirable in differential circuit applications.

   • True
   • False

   Hint

   Consider the impact of noise in circuit performance.

5. 5.

   You have a differential amplifier with two inputs, one at 3V and the other at 1V. If the common-mode gain is 1, what would the output voltage when the common mode signal is 0.5V?

   Hint

   Break the equation down into its components.

6. 6.

   Describe how you would analyze a differential amplifier implementing the small signal approximation directly using Kirchhoff's laws.

   Hint

   Start with a single input and trace current paths through the circuit.