Electric Circuits 8th Edition 114

Electric Circuits 8th Edition 114 - control c cuits In this...

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90 Simpte Resistjve Cncuits b) To fitrd Rb as a function of n1, R2, and R3, take advantage of the derivations obtained by hint (1), namely, Eqs 3.44-3.46. Note that these equa- tions can be divided to obtait GzGz Gr+G2+G3' GGz Gt+GziGt' GtGz G\+G2+G3' b !--Rr- t--. .1 d Attenuator a) The fixed-attenuator pad showl in Fig. P3.64 is called a brillgel tee. Use a Y{o-A transforma- tion to show that Rab : RL if R = RL. b) Show that when R : RL, the voltage ratio o,/o, equals 0.50. Flgue P3.54 " i________,_ I ' Fixed-attenuator pad The design equations for the bddged-tee attenuator circuit in Fig. P3.65 are 2RRi R2 R^ R. = ;, or R, = ;Rb, ^b and xr Ro ^ R2^ &:&. .' ^,:x^' Now use these ratios in Eq.3.43 to eliminate and Use similar manipulations to find Ra and as functions ol R1, R2, and R3. Show that the expressions for A conductances as lunctions of the three Y conductances are 3.64 ^1^1 r, : o. r. : erc. Seclions 3.1-3.7 R2 2R1 -r R2 + RL
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Unformatted text preview: control c cuits. In this application, they are refened to as resr.rtdrce atknu&tors or pads. A typr-cal fixed-attenuator pad is shown in Fig. P3.63. In designiDg an drlenuado0 pad. lbe circuil designer will select the values of R1 and R2 so that the iatio of r,/oi and the resistance seen by the input voltage souice R"6 both have a speciJied value. a) ShowthatifRab: RL, then R i : 4 R r ( R 1 + R ) , 3 n - R L 3R + RL' when R2 has the valuejust given. a) Design a fixed attenuator so tlat oi : 3oo when R L : 6 0 0 o b) Assume the voltage applied to the input of the pad desigtred in (a) is 180 V Which iesistor in the pad dissipates t}le most power? c) How much power is dissipated in the resistor in part (b)? d) Which rcsistor in the pad dissipates the least e) How much power is dissipated ill the resistor in part (d)? b) Select the values of R1 and R2 Rab - RL = 600 O and 0,/?,r : 0.6. so that...
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This note was uploaded on 07/05/2010 for the course EE 100 taught by Professor Boser during the Spring '07 term at Berkeley.

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