75.5.3. Active Devices for Enhanced Performance

Try these first

1. 1.

   What does a differential amplifier amplify?

   Hint

   Think about what is fed into the amplifier.

2. 2.

   Name one type of active device used in differential amplifiers.

   Hint

   Consider the components that can control current or voltage.

3. 3.

   What is the primary function of a differential amplifier?

   • To amplify a single input signal
   • To amplify the difference between two input signals
   • To reduce signal noise

   Hint

   Remember what we discussed at the beginning about amplification.

4. 4.

   True or False: Differential mode gain should be as low as possible in a well-functioning amplifier.

   • True
   • False

   Hint

   Think about the goals of an amplifier.

5. 5.

   A differential amplifier has a differential mode gain of 25 and a common mode gain of 2. If both inputs receive a common signal of 1V, what will the outputs be?

   Hint

   Use A_d and A_c in conjunction with the input signals.

6. 6.

   Design a conceptual circuit diagram for a differential amplifier using BJTs. Describe the components needed and their placements.

   Hint

   Map out the path data follows through the circuit.