15.2.4. Concept of Transconductance

Try these first

1. 1.

   What is transconductance?

   Hint

   Think about how input voltage changes affect current output.

2. 2.

   Why is the Q-point important in amplifier design?

   Hint

   Consider how operating points relate to output signal quality.

3. 3.

   What does transconductance (g_m) measure?

   • Current to Voltage ratio
   • Voltage to Current change
   • Current change per Voltage change

   Hint

   Focus on what happens to current when voltage varies.

4. 4.

   True or False: The Q-point should always be set at the highest part of the output characteristic curve for maximum amplification.

   • True
   • False

   Hint

   Consider the implications of different operating points.

5. 5.

   If a common emitter amplifier has a transconductance of 40 mA/V, and the base voltage increases by 0.05 V, what will be the change in collector current?

   Hint

   Use the transconductance formula.

6. 6.

   A BJT amplifier enters saturation when the collector current exceeds 10 mA. If the collector current is initially 8 mA, what range of increase in input voltage would keep it within linear operation?

   Hint

   Consider g_m for your calculations and ensure the collector current remains less than 10 mA.