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(ELEC101)[2010](s)midterm2~716^_10275.pdf
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1. The circuit below contains a voltage-dependent Find cunent I
voltage'source.
+
Vx 2A

9Vx + 3I -V7=o
(VL o{ o*+c-r""P' =) 3l .7QQ=e
-(t)
-!kqr.t Vu= -(t-z) L2
'""
=>
2L+ Vx @ BL + 4v'. --tL '(1\
(21-(, \ 9l rt
'
.-.-------"-2 L_
+-
Find and draw the Thevenin and Norton equivalentcircuits with respect to the teminals a, b for the below circuit with a cunent-dependent voltage-source.I.e. Find V111, R11 and 11, Rp. .
h'([t, ET-* a..vta4 }ib : -t)+,iy-1" ir. r(
Va4,.)r1r.) + r)r --triP=zt)-
Vt11' 2>rV
t),
.iJ + lot V Bh% | A c',-t*I r 'v'a-, ia= | 4 Vr ' toir+ f)v' tray , lrv
k,"h- IX (n ,l rrblr_J
^, ILA n-I[t, !q?*aet':'-t2ulv n -? lr.: + 7s.--o t]--iy
/ttr''n , (d)v t lit *o
6P us F:v4)
tl\4.Uta. ^
i ln-
229V trA I 7trL

3. Assumethe op amp is ideal. Find thevoltage gain Vo/Vs of the amplifier structure shown below.
3 v, =+k
?.(a v+'v-= ] v, I
l<vL 4lu-I'
'
"t
4' 2Uo-Urs
-q
Ve
lo'

->lr: II
Jvt
4

4. (a) The below circuit is a cu ent cmplifier consist of an ideal op amp. De ve expressionfor the current gain Io"/Is in terms ofRt and R:.
i current i amplifier
I5
-1"R, ,(I"-7,)(,
1o(Rt1 P,) = 7-P,
:)
'Pt1?,
tt f.t
(21 -
(b) Derive an expressionfor the input resistance of the curent amplitier in terms of R;, R1 and R2.
l-IsQ, + lr 12,

h.. lt -1-
k

l-:-Lo-le. * /t + A \D
I ' \' tz, /l-L
t"
I
6


5. (a) Assurneth switch in th belolv circuit has been opened for a long timc. Whan tlle switah closed at t = 0, find the value ofi(t) for t = 0- and i(t) for t > 0.
(01
(,'c . sL"i"t

fit L.o', ;Lfl f d<.A ehte )
i(()= r4

alA

rrt t>o , ) to<),4Lr')
r 2+
i7*;. 1, + -.--a-= tt.LY t t.\v'n
lr-r -!
ts'4r

' 'lo''
t.vY-)e
" 4t+2.1 /.Q\' -
'

Iav -4,-
Pb
/.+! -o,

(b) Plot(0 fort<0 andt>0.
i.+t
7


(a) Assurnetheswitoh in the bclow circuit hasbenopencd for a long time. When the switch closcdat t =0, lind 0rc valuc ofv(t) for t = 0-and v(t) for t > 0.
+ v(t) -
+
0.lH
ux .4iat

4{ +=o' &ur;k't"dp<^ ic+)"t rtu$ c+,cz
, ,
v(-o-)=-e--'-'^v'F7l

4(0')= /o o tA
E;7.

4+1>" )@4),;(o')= tA. ti9.
iles=
'-r"A 0..,..,__ J)

<.-h . . s.o^
lollto s ",., .t/ont_^ ' -lt '' 4,oz_
-^ -
1o'Je

i(+>.) ro'(t-to)e'' -
-too-v(tv')h(La") -

a:=:P + ibt'z') -o
Kct ,a@S
-':9t: -

= (60 I ta4(t4a)2VL47.")
vL+>,o).yv * sf(1.'l>"'4'"'J
'4s"'4,'#

' 'oo
(b) Plotv(t)fort<0 andt>0.
vLt )

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