Question
What is the frequency response of the circuit in E7-3 if a capacitor is added across the feedback resistor?
Answer Options
- A) High-pass filter
- B) Low-pass filter
- C) Band-pass filter
- D) Notch filter
Correct Answer: B
Explanation
Figure E7-3 shows a basic inverting operational amplifier configuration, which amplifies all frequencies equally in its basic form. Adding a capacitor across the feedback resistor (R_F) changes the characteristics of the negative feedback and transforms the amplifier into an active filter circuit.
In this configuration, the capacitor provides a low-impedance path to ground at high frequencies. This causes the feedback impedance to decrease as frequency increases, which reduces the overall amplifier gain (Gain = -Z_F/R_1). Therefore, the circuit becomes a Low-pass filter, attenuating high frequencies while maintaining a stable gain for low frequencies and \text{DC}.
This topic was automatically created to facilitate community discussion about this exam question. Feel free to share study tips, memory tricks, or additional explanations!