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An amplifier has an open loop gain of 100, an input impedance of 1kΩ, and an out put impedance of 100 Ω. If a feedback network with a feedback factor of 0.99 is connected in a voltage series feedback mode then new input and output impedances are
(a)
(b)
(c)
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- 10 Ω and 1 Ω
- 10 Ω and 10 k Ω
- 100 k Ω and 1 Ω
- 100 kΩ 10 k Ω
Correct Option: C
Zif = Zi (1 + βA) = 1 k (1 + 100 × 0.99) = 100 kΩ
| Zof = | = | = 1 Ω | ||
| 1 + βA | 100 |
