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(ELEC101)[2009](s)midterm~kkcheungab^_10264.pdf
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l. (a) Write 7.75 decimal in binary form. -" J,--(:: (j, S </ -0, '>
2"::4-.;/-4-
)_2:;. 0,"2->00/ :; OJ ?)
2' :: z.v I -2-
0,7 (
7

(b) i) Write out the truth table for F =AB .
ii) Draw F =A B using NAND gates only. Only A and B are available.
iii) What single logic gate could be used to give the same output for all inputs of A and B?
i) A 8


0
()
D
0
0
f
{0
(
V
0
( I
:J
u 0
I
,',. )
Ii >"~ F
1)-
r; 1)0 r

; =:[)(~ -I>
__-=:_ D

I:::
2 -l--fO_12 U_ A rE]
2. A logic function has 4 inputs ABeD and J output F. lts truth table is shown as follow. X is "don't care". Use K-Map to simply the function F.
A B C D F
0 0 0 0 0
0 0 0 1 1
0 0 1 0 X
0 0 ] \ 0
0 1 0 0 1
0 1 0 1 I
0 I I 0 ]
0 I I I 1
I 0 0 0 0
I 0 0 1 I
I 0 1 0 0
I 0 I I X
I I 0 0 1
I ] 0 ] X
I I I 0 I
1 I 1 I 0


U
/0 -------Bv7

,.
-t
/F : t) 6 -t-cJ> l
3
3. Complete the following timing diagram. Both JK flip flops (Ql and Q2) are initially reset to O. The transition table of the JK flip-flop is shown below.
J 0 0
K FUNCTION eLK Q,,+l Qn+\
0 NO CHANGE i Qn Q"
RESET i 0 1
0 SET i 0
1 ; TOGGLE i Qn Qn


c I T


Ql l~L__'r
~L._. .-. rr':I~: ---.J"'l~:"


4

4. Find Yo in the below circuit using nodal analysis (node voltage analysis). Find the power delivered by the 2A current source.
50.

\,..1.>
-~ to &-":f.,
-r.., -)

LJ <)
r~r I
-------'
2-cf!
-<)
..<-7--.:--J
I -r r -f 77 --0
( -J...
_ I/o
'f)
o--1I~
2--r--+ --U
D
S-
.-
~
S-J
-[T/u [/1
r;O
V".-::
(
~

cof e /,' v~ r '"-rJ)
~
f~A J V 1-/
-(c;.:;)(])
-
/0 0 Ivt//
?Vl deI,v=1/
5

5. Use mesh analysis to find 10 in the below network. 2A
.---------1 ..... l---------,
40 20.


6V

--e_ 2A
e--) Z3
L[. /
r-----.AJV-__.__. 1\. J.-..

6v
?LJ~ 3 ~12




:): v=-0
VI +-V1-f v3 ::.. 0 C l, -7-1 ):; f (-T) -]:2)).
-f--(-6)~o

T~ ~ If -L 2-
-;:; U _- 0/ y:
[IJ -=- 3/ (; A 7
6

l
1
I
6. Use the principle of superposition to find the voltage Vo in the below circuit.
I
i In
!

I
I

+
I
3A Vo
20
1 6V
I
I
I


--vv-.:
! I @
I)
( 2} J 2 ~/
Gi
,
12
Vi/I -=-
LI+2-) 6
l~L)( ~3Vl

[
If --C-L) 9 ::: 3A
7--+ I
-
~> -C 4) (~) v() 2.--(3) (~)
[Cro .)---" 6 V7
'-f.-f
-rt+ Lt~ ---I -+ 2-c:.-6
~c' [,~
-
/-~~
-/0 i/7
7

7. (a) Find the Thevenin and Norton equivalent with respect to the terminals a, b for the below circuit. I.e. Find Vnl, RTH and IN-RN.
lA
-+ 2Q a
6V 20 b

~dJ

2 c'-6 F; /fL )
~ 1;en J<-iA -- IJl 1



-t-/
I
r-
Is c



i/.v: ~ 0e-/ R-d, .;: (~) (r)
rV<i, ~ if-l/7
8
(b) Draw the Thevenin and Norton equivalent circuits at below.
f2~ ~ f-J'l -t~ t\


c\,

(c)