This twostage swamped amplifier has an overall voltage gain of 502 without twostage negative feedback.
The input impedance is 1.32KΩ and the output impedance is 3.6KΩ.
When I implement twostage negative feedback (schematic attached), the voltage gain drops to 210.
Av = 502
β = RE11 / RE11 + RF = 50Ω / 50Ω + 18KΩ = 0.00277
ACL = Av / (1 + (Av * β)) = 502 / (1 + (502 * 0.00277) = 210
I understand from my research that in order for ACL to be stable within +/ 1%, Av should be equal to or
greater than 100 * ACL. That would mean that either Av would have to be 21,000 or ACL would have to
be ACL would have to be 5.02. What am I missing?
Newbie2019
The input impedance is 1.32KΩ and the output impedance is 3.6KΩ.
When I implement twostage negative feedback (schematic attached), the voltage gain drops to 210.
Av = 502
β = RE11 / RE11 + RF = 50Ω / 50Ω + 18KΩ = 0.00277
ACL = Av / (1 + (Av * β)) = 502 / (1 + (502 * 0.00277) = 210
I understand from my research that in order for ACL to be stable within +/ 1%, Av should be equal to or
greater than 100 * ACL. That would mean that either Av would have to be 21,000 or ACL would have to
be ACL would have to be 5.02. What am I missing?
Newbie2019
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