# E7G02 - What is the frequency response of the circuit in E7-3 if a capacitor is added across the feedback resistor?

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**Category:** Extra Questions\
**Created:** [January 2, 2026, 7:53pm UTC](https://forum.openhamprep.com/t/e7g02-what-is-the-frequency-response-of-the-circuit-in-e7-3-if-a-capacitor-is-added-across-the-feedback-resistor/1413 "2026-01-02T19:53:24Z")\
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**Author:** ![system](https://forum.openhamprep.com/uploads/default/original/1X/a8bc13ef992b522befd6b1d923d2f2a53605a9c7.png) [@system](https://forum.openhamprep.com/u/system)\
**Post date:** [January 2, 2026, 7:53pm UTC](https://forum.openhamprep.com/t/e7g02-what-is-the-frequency-response-of-the-circuit-in-e7-3-if-a-capacitor-is-added-across-the-feedback-resistor/1413/1 "2026-01-02T19:53:24Z")

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## Question

What is the frequency response of the circuit in E7-3 if a capacitor is added across the feedback resistor?

 ![E7-3](https://forum.openhamprep.com/uploads/default/original/1X/3ee24bb7bfac94f54f6c532b9c61fcad35845035.png)

## Answer Options

- **A)** High-pass filter
- **B)** Low-pass filter
- **C)** Band-pass filter
- **D)** Notch filter

**Correct Answer: B**

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## 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}.

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