Question

What is theimpedance from the input port according to Millers Theorem?

(a) Zin1 = Z × K / 1 – K

(b) Zin1 = Z × K / 1 + K

(c) Zin1 = Z / 1 – K

(d) Zin1 = Z / 1 + K

The question was asked by my school principal while I was bunking the class.

This intriguing question originated from Frequency Response topic in division Frequency Response of Electronic Devices & Circuits

Answer 1

The correct option is (c) Zin1 = Z / 1 – K

To explain I would say: According to Millers Theorem, to calculate the input impedance from the input port we use: Zin1 = Z / 1 – K. Where, Z is the original circuit impedance and K is the ratio of the two nodal voltages V2 / V1.