Amp Up Your Knowledge: 2026 Electronics Engineering Board Exam Bash!

To determine the output impedance (Z₀) of an op-amp in a feedback configuration, one needs to consider the open-loop gain (A), the feedback resistors (R_f and R₁), and the output resistance of the op-amp (r₀).

In this scenario, we have the following values:

- Open-loop gain (A) = 200,000 (200 kΩ)

- Output resistance (r₀) = 75 Ω

- Feedback resistor (R_f) = 360 kΩ

- Input resistor (R₁) = 12 kΩ

The relationship for calculating the output impedance in a feedback configuration is:

Z₀ = r₀ / (1 + Aβ)

Where β is the feedback factor, which can be calculated as:

β = R₁ / (R₁ + R_f)

Substituting the given values to find β:

β = 12 kΩ / (12 kΩ + 360 kΩ) = 12 kΩ / 372 kΩ = 0.03225806.

Now we can calculate the term (1 + Aβ):

1 + Aβ = 1 + 200,000 *