Section 11.1: The General Feedback Structure 11.1 A newly constructed feedback amplifier under- goes a performance test with the following results: With the feedback connection removed, a source signal of 1 mV is required to provide a 1-V out- put; with the feedback connected, a 1-V output requires a 0.1-V source signal. For this amplifier, identify values of A,B, and AB, the closed-loop gain, and the amount of feedback in dB. Section 11.2: Some Properties of Negative Feedback 11.2 An amplifier with a midband gain of 1000 V/V has a lower 3-dB frequency fz of 100 Hz and an upper 3-dB frequency H of 100 kHz. The gain falls off at a rate of 20 dB/decade at both the low and the high-frequency ends. If negative feedback is applied to this amplifier so that its midband gain becomes 10 V/V, find the 3-dB frequencies of the closed-loop amplifier. Also, sketch a Bode plot for the magnitude of both the open-loop and closed- loop gains, in the same figure. If the open-loop gain has a tolerance of ±10%, what do you expect the tolerance of the closed-loop gain to be?

Fig: 1