Prof Razabi's lectures are easy and to the point. He is the great. teacher. Thanks and respect.

This is how people should always teach....greatest lecture series of all time on electronics

Thank you always Prof. Razavi, I am a student in S. Korea and I achieved a satisfying grade on my midterm exam all because of your excellent lectures.

thank you sir!!

Thank You

01:16 Today's focus is on understanding voltage-voltage feedback. 04:16 Understanding Four Feedback Topologies 10:08 Different feedback topologies for impedance amplifiers 13:11 Different feedback topologies have different features and affect the output impedance. 19:11 Using feedback to adjust the overall voltage gain. 22:06 Key points about input and output impedances in voltage-voltage feedback topology 27:08 Analysis of feedback topologies with voltage and current 30:17 Negative feedback increases input impedance in voltage-voltage amplifiers. 35:09 Finding closed-loop output impedance 37:58 Feedback reduces output resistance by a factor of (1 + Ka) 43:22 Voltage-Voltage (Shunt-Series) Feedback Topology discussed. 45:57 Voltage-Voltage Feedback Topology Characteristics Crafted by Merlin AI.

01:25 - Intro and Review 05:14 - Four Feedback Topologies 14:22 - Objectives 16:55 - Analysis of Voltage-Voltage Feedback: Closed-Loop Gain 22:15 - Analysis of Voltage-Voltage Feedback: Impedances 23:43 - Analysis of Voltage-Voltage Feedback: Input Impedance 33:05 - Analysis of Voltage-Voltage Feedback: Output Impedance 42:45 - Transistor-Level Example

Thank you

While calculating the output impedance, why do we consider polarity (+ and -) for Vx and AVi? What would be the equation for AC sources?

You have your topology naming backwards. What you labeled as shunt-series is really series-shunt. You explained it correctly, but the common naming convention is input-output. Input is in series and output is shunted, so the name should be series-shunt as opposed to how you labeled it, shunt-series.

These are extremely useful lectures for which I am very grateful. I have some doubt though: When the Prof speaks in many locations including here at about 18:26 explaining how Vin and the Return voltage U are connected in series to build the difference Vin-U. Here he mentioned repeatedly that Vin, U and the input of A1 are all connected in series. Here is where I have doubt: I agree that Vin and U are connected in series and at the resulting two terminals of this connection we have Vin-U. This difference is in my opinion connected in parallel to A1 input as A1 is supposed to sense (measure) this difference exactly the same way a Voltmeter would be connected to measure (sense) the difference. Am I mixing something here?

28:30 - Input impedance is being bootstrapped (Miller Effect) and thus lowered by the negative feedback. For inverting amplifier configuration, the configuration would be called Voltage-Current/Shunt-Shunt?

god