44.6. Small Signal Equivalent Circuits

Try these first

1. 1.

   What is the main function of a common collector amplifier?

   Hint

   Think about where the input and output are connected.

2. 2.

   Why do we bias a transistor?

   Hint

   Consider what happens without biasing.

3. 3.

   What configuration does a common collector amplifier use?

   • Emitter as output
   • Base as output
   • Collector as output

   Hint

   Think about where the output signal is taken.

4. 4.

   True or False: The voltage gain of a common drain amplifier can be significantly less than 1.

   • True
   • False

   Hint

   Recall the behavior of buffers.

5. 5.

   Given a common collector amplifier with a known input resistance of 100 kΩ and an output load of 50 kΩ, calculate the expected output voltage when a 1 V input signal is applied.

   Hint

   Consider how voltage divides between parallel resistances.

6. 6.

   A MOSFET common drain amplifier has a transconductance of 2 mS. Calculate the output current if the gate voltage changes by 1 V.

   Hint

   This uses the basic relationship with transconductance.