Sol4 - ECE 255 ELECTRONIC ANALYSIS AND DESIGN Homework 4...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Vcc R1 R2 Rc Re Vcc v s R S ECE 255 ELECTRONIC ANALYSIS AND DESIGN Fall 2009 Homework 4 Solutions Problem 1 (Text 13.60) Compute A Vs The ac equivalent circuit for an amplifier is shown. Assume the capacitors have infinite value and that R S = 750 , R B = 100 k , R C = 100 k , and R 3 = 100 k . Calculate the voltage gain of the amplifier if the BJT Q -point is {50 μ A, 10 V}. Assume β 0 = 100 and V A = 75 V. d 75V 10V r 1.70M 50 A + = = μ ( 29 m g 38.92 50 A 1.95mS = μ = and 100 r 51.4k 1.95mS π = = ( 29 i V m C 3 d A g R R r 1.95m 48.6k 94.8 = - = - × = - ( 29 S i B π V V S B π R r 33.9 A A 94.8 92.8 R R r .75 33.9 = = - = - + + Problem 2 (Text 13.61) For β 0 = 100 see Problem 1 above (Text problem 13.60) π BB B π 60 r 30.8k and R R r 100k 30.8k 23.6k 1.95mS = = = = Ω = ( 29 i V m C 3 d A g R R r 1.95m 48.6k 94.8 = - = - × = - ( 29 S i B π V V S B π R r 23.6 A A 94.8 91.9 R R r .75 23.6 = = - = - + + Problem 3 Design a four resistor bias network to achieve the operating point given in Text problem 13.60 with the following restrictions, R th = R B , R C = R C , and V CC = 20 V. Assume V BE = V 0 = 0.7V. C R V 100k 50 A 5V = Ω× μ = E R V 5V = ( 29 ( 29 E R E V 50.5 A R 5V C B E I I R = + = μ = E R 99k = To determine R 1 and R 2 we have the following relationships: th 1 2 R R R 100k = = , ( 29 E 1 1 CC BE R 1 R R V V V 20 0.7 5 V R I I - - - - = = , and ( 29 E 1 1 BE R 2 R B R V V 0.7 5 V R I I I 0.5 A + + = = - - μ Since 1 2 R 2 R × , R 2 can not be larger than 150 k
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/20/2010 for the course ECE 255 taught by Professor Staff during the Spring '08 term at Purdue University-West Lafayette.

Page1 / 4

Sol4 - ECE 255 ELECTRONIC ANALYSIS AND DESIGN Homework 4...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online