60.1.3. Input Resistance Calculation

Try these first

1. 1.

   What is the basic function of a common collector amplifier?

   Hint

   Remember its role in interfacing with high-resistance sources.

2. 2.

   If Q1 has a current gain (β) of 100, what is the base current for an emitter current of 1 mA?

   Hint

   Use the formula relating emitter current and base current through β.

3. 3.

   What is the primary purpose of the common collector stage in an amplifier?

   • To provide low input resistance
   • To maintain high input resistance
   • To increase output current

   Hint

   Consider the input characteristics of high source resistance.

4. 4.

   The input resistance of a CE amplifier is affected by which key factor?

   • True
   • False

   Hint

   Think about how amplifier configuration affects loading effects.

5. 5.

   Given a circuit with R1 = 47 MΩ and β = 150, if the emitter current of Q1 is 1.2 mA, calculate the input resistance.

   Hint

   Consider how to combine resistance values properly.

6. 6.

   In a CE configuration with a Darlington pair, calculate the input impedance and comment on the resulting bandwidth.

   Hint

   The trade-off is crucial in amplifier design decisions.