# 12Spring_hw03 - v s +-R s R L +-R in +-+ -v in A v in R o...

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ECE210/211 - Spring 2012 - Homework 03 1. Consider the circuit framed by the dashed curve: 3 Ω 6 V + - R L (a) What is the available power to the load resistor R L ? (b) What load resistance R L maximizes the power extracted from the circuit? (c) What is the “power eﬃciency” P L P S expression for this network, where P S is the power supplied by the 6 V source as a function of R L ? (d) What is the power eﬃciency obtained by the maximum power load that you found in part (b)? where does the remaining “wasted power” go? (e) What load resistance R L will result in a 90 % power eﬃciency? How much power is extracted from the network in this case? (f) What load resistance maximizes the power eﬃciency? How much power is extracted from the network in this case? 2. (a) Show that the voltage follower op-amp circuit + - v s + - R s v L R L + - v + v - can be modeled as below by applying the model in section 3.1 of the textbook.
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Unformatted text preview: v s +-R s R L +-R in +-+ -v in A v in R o v-v + v L (b) Find v L in terms of v s using this model. What is the voltage gain ± v L v s ² of this circuit? (c) Using typical numbers for a microphone pre-amp circuit, R S = 10 k Ω , R in = 1 M Ω , R o = 1 Ω , R L = 100 Ω , A = 10 5 in the previous model, what is the voltage gain of this circuit? (d) Using the ideal op-amp approximations in the ﬁrst circuit, ﬁnd the voltage gain of the circuit and compare it to that of the more accurate voltage-dependent voltage source model. 3. Find the Thevenin equivalent circuit between A and B for the following circuit, assuming the ideal op-amp approximation. +-. 3 cos (880 π t ) V +-1000 Ω +-B A 5000 Ω 2 Ω 4. Textbook problem 3.3 5. Textbook problem 3.4 6. Textbook problem 3.6 1...
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## This note was uploaded on 03/28/2012 for the course ECE ece210 taught by Professor Ece during the Spring '10 term at University of Illinois, Urbana Champaign.

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