68.1.11. Input Capacitance and Cutoff Frequency

Try these first

1. 1.

   Define input capacitance.

   Hint

   Think about what all components could contribute to this capacitance.

2. 2.

   What is cutoff frequency?

   Hint

   How does gain relate to this frequency?

3. 3.

   What does input capacitance determine in an amplifier?

   • Frequency response
   • Overall gain
   • DC biasing

   Hint

   Think about how capacitance impacts signal behavior.

4. 4.

   True or False: Lowering the input capacitance increases the cutoff frequency.

   • True
   • False

   Hint

   Related to how frequency and capacitance interact.

5. 5.

   Given a circuit with a load capacitance of 150 pF, an output resistance of 30 kΩ, calculate the new cutoff frequency of the circuit.

   Hint

   Use the formula for cutoff frequency and plug in the given values.

6. 6.

   An amplifier exhibits a voltage gain of 2500 and has an input capacitance of 12 nF. Calculate the effective input capacitance when this gain is applied and find the impact on frequency response.

   Hint

   Use the capacitance formula that includes voltage gain.