# hw05 - ECE 488: RF Circuits and Systems Spring 2009...

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Unformatted text preview: ECE 488: RF Circuits and Systems Spring 2009 HOMEWORK 5: Transistor Bias, Power Supplies, Smith Charts Reference: Lectures 3, 1014; Chapters 3, 810, 16 Due: February 25 Problem 1: We will study the RF behavior of the circuit shown below later in this course. For now, just determine the DC bias on all nodes of the tran- sistors. Give numerical answers. [20 points] Figure 1: A negative resistance oscillator. C1=1500 pF, L1=47 H. Problem 2. Design a DC-DC converter to deliver 15 kV to a parallel combination of a 1000- load and 10- load from a 100-V battery. The switch cycle time is to be 1 + 2 = 500 s. [25 Points] a. Draw the complete circuit. (See the Hagen text or your notes for a choice of circuits.) b. What is the critical value for the inductor? c. With an inductor twice as big as found for part (b), what is the minimum capacitance needed to keep the ripple under 1-volt peak? Clearly state any assumptions....
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## This note was uploaded on 04/01/2009 for the course ECE 488 taught by Professor Swartz during the Summer '08 term at Cornell University (Engineering School).

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