75.3.2. Common Mode Gain and Differential Mode Gain

Try these first

1. 1.

   What is the definition of differential mode gain?

   Hint

   It relates to the input signals' opposition.

2. 2.

   What should the ideal common mode gain be?

   Hint

   Think about noise rejection.

3. 3.

   What is the main function of a differential amplifier?

   • To amplify both input signals equally
   • To amplify the difference between two input signals
   • To amplify noise

   Hint

   Focus on the word 'difference'.

4. 4.

   True or False: Common mode gain should be maximized for better performance.

   • True
   • False

   Hint

   Remember desired amplifier properties.

5. 5.

   Design a differential amplifier circuit using BJTs and calculate its expected differential and common mode gain based on specific resistor and input values.

   Hint

   Focus on input-output relationships.

6. 6.

   Given a common mode gain of 1.5 and a differential mode gain of 25, what is the common mode rejection ratio (CMRR)?

   Hint

   Look for the ratio of gains.